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Sample records for ole hjorth caspersen

  1. OLED area illumination source

    SciTech Connect

    Foust, Donald Franklin; Duggal, Anil Raj; Shiang, Joseph John; Nealon, William Francis; Bortscheller, Jacob Charles

    2008-03-25

    The present invention relates to an area illumination light source comprising a plurality of individual OLED panels. The individual OLED panels are configured in a physically modular fashion. Each OLED panel comprising a plurality of OLED devices. Each OLED panel comprises a first electrode and a second electrode such that the power being supplied to each individual OLED panel may be varied independently. A power supply unit capable of delivering varying levels of voltage simultaneously to the first and second electrodes of each of the individual OLED panels is also provided. The area illumination light source also comprises a mount within which the OLED panels are arrayed.

  2. OLED devices

    SciTech Connect

    Sapochak, Linda Susan; Burrows, Paul Edward; Bimalchandra, Asanga

    2011-02-22

    An OLED device having an emission layer formed of an ambipolar phosphine oxide host material and a dopant, a hole transport layer in electrical communication with an anode, an electron transport layer in communication with a cathode, wherein the HOMO energy of the hole transport layer is substantially the same as the HOMO energy of the ambipolar host in the emission layer, and the LUMO energy of the electron transport layer is substantially the same as the LUMO energy of the ambipolar host in the emission layer.

  3. Release of OLe peanut

    USDA-ARS?s Scientific Manuscript database

    OLe is a high oleic Spanish-type peanut that has excellent yield and enhanced Sclerotinia blight and pod rot resistance when compared to other high oleic Spanish cultivars. The purpose for releasing OLe is to provide peanut producers with a true Spanish peanut that is high oleic and has enhanced yi...

  4. High Brightness OLED Lighting

    SciTech Connect

    Spindler, Jeffrey; Kondakova, Marina; Boroson, Michael; Hamer, John

    2016-05-25

    In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

  5. OLED panel with fuses

    SciTech Connect

    Levermore, Levermore; Pang, Huiqing; Rajan, Kamala

    2014-09-16

    Embodiments may provide a first device that may comprise a substrate, a plurality of conductive bus lines disposed over the substrate, and a plurality of OLED circuit elements disposed on the substrate, where each of the OLED circuit elements comprises one and only one pixel electrically connected in series with a fuse. Each pixel may further comprise a first electrode, a second electrode, and an organic electroluminescent (EL) material disposed between the first and the second electrodes. The fuse of each of the plurality of OLED circuit elements may electrically connect each of the OLED circuit elements to at least one of the plurality of bus lines. Each of the plurality of bus lines may be electrically connected to a plurality of OLED circuit elements that are commonly addressable and at least two of the bus lines may be separately addressable.

  6. OLEDS FOR GENERAL LIGHTING

    SciTech Connect

    Anil Duggal; Don Foust; Chris Heller; Bill Nealon; Larry Turner; Joe Shiang; Nick Baynes; Tim Butler; Nalin Patel

    2004-02-29

    The goal of this program was to reduce the long term technical risks that were keeping the lighting industry from embracing and developing organic light-emitting diode (OLED) technology for general illumination. The specific goal was to develop OLEDs for lighting to the point where it was possible to demonstrate a large area white light panel with brightness and light quality comparable to a fluorescence source and with an efficacy comparable to that of an incandescent source. it was recognized that achieving this would require significant advances in three area: (1) the improvement of white light quality for illumination, (2) the improvement of OLED energy efficiency at high brightness, and (3) the development of cost-effective large area fabrication techniques. The program was organized such that, each year, a ''deliverable'' device would be fabricated which demonstrated progress in one or more of the three critical research areas. In the first year (2001), effort concentrated on developing an OLED capable of generating high illumination-quality white light. Ultimately, a down-conversion method where a blue OLED was coupled with various down-conversion layers was chosen. Various color and scattering models were developed to aid in material development and device optimization. The first year utilized this approach to deliver a 1 inch x 1 inch OLED with higher illumination-quality than available fluorescent sources. A picture of this device is shown and performance metrics are listed. To their knowledge, this was the first demonstration of true illumination-quality light from an OLED. During the second year, effort concentrated on developing a scalable approach to large area devices. A novel device architecture consisting of dividing the device area into smaller elements that are monolithically connected in series was developed. In the course of this development, it was realized that, in addition to being scalable, this approach made the device tolerant to the most

  7. A look inside white OLEDs

    NASA Astrophysics Data System (ADS)

    Bobbert, Peter; Coehoorn, Reinder

    2013-09-01

    White organic light-emitting diodes (OLEDs) for lighting are finding their way to the market. These OLEDs have organic layers only a few nanometres thick. Improving their efficiency and stability requires nanometre-precision information about where the light is emitted. Reconstruction of the emission profile from the measured emission and molecular-scale modelling provide a unique nanoscale look inside white OLEDs.

  8. OLED Lighting Products: Capabilities, Challenges, Potential

    SciTech Connect

    Miller, N. J.; Leon, F. A.

    2016-05-31

    A report that focuses on the potential for architectural OLED lighting – describing currently available OLED products as well as promised improvements, and addressing the technology and market hurdles that have thus far prevented wider use of OLEDs.

  9. OLED with improved light outcoupling

    SciTech Connect

    Forrest, Stephen; Sun, Yiru

    2016-11-29

    An OLED may include regions of a material having a refractive index less than that of the substrate, or of the organic region, allowing for emitted light in a waveguide mode to be extracted into air. These regions can be placed adjacent to the emissive regions of an OLED in a direction parallel to the electrodes. The substrate may also be given a nonstandard shape to further improve the conversion of waveguide mode and/or glass mode light to air mode. The outcoupling efficiency of such a device may be up to two to three times the efficiency of a standard OLED. Methods for fabricating such a transparent or top-emitting OLED is also provided.

  10. Virtual screening for OLED materials

    NASA Astrophysics Data System (ADS)

    Halls, Mathew D.; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang; Kwak, H. Shaun; Gavartin, Jacob

    2014-10-01

    Organic light-emitting diodes (OLEDs) are under widespread investigation to displace or complement inorganic optoelectronic devices for solid-state lighting and active displays. The materials comprising the active layers in OLED devices are selected or designed to provide the required intrinsic and extrinsic electronic properties needed for efficient charge injection and transport, and desired stability and emissive properties. The chemical design space for OLED materials is enormous and there is need for the development of computational approaches to help identify the most promising chemical solutions for experimental development. In this work we present a multi-scale simulation approach to efficiently screen libraries of potential OLED molecular materials. The workflow to assess potential OLED materials is: 1) evaluation based on first-principles prediction of key intrinsic properties (EHOMO, ELUMO, λe/h, Etriplet), 2) classical simulation of thin film morphology (RDF, ρ), and 3) first-principles evaluation of electron coupling for donor-acceptor pairs (Hab) from the simulated condensed phase morphology.

  11. OLED study for military applications

    NASA Astrophysics Data System (ADS)

    Barre, F.; Chiquard, A.; Faure, S.; Landais, L.; Patry, P.

    2005-07-01

    The presentation deals with some applications of OLED displays in military optronic systems, which are scheduled by SAGEM DS (Defence and Security). SAGEM DS, one of the largest group in the defence and security market, is currently investigating OLED Technologies for military programs. This technology is close from being chosen for optronic equipment such as future infantry night vision goggles, rifle-sight, or, more generally, vision enhancement systems. Most of those applications requires micro-display with an active matrix size below 1". Some others, such as, for instance, ruggedized flat displays do have a need for higher active matrix size (1,5" to 15"). SAGEM DS takes advantages of this flat, high luminance and emissive technology in highly integrated systems. In any case, many requirements have to be fulfilled: ultra-low power consumption, wide viewing angle, good pixel to pixel uniformity, and satisfactory behaviour in extreme environmental conditions.... Accurate measurements have been achieved at SAGEM DS on some micro display OLEDs and will be detailed: luminance (over 2000 cd/m2 achieved), area uniformity and pixel to pixel uniformity, robustness at low and high temperature (-40°C to +60°C), lifetime. These results, which refer to military requirements, provide a valuable feedback representative of the state of the art OLED performances.

  12. Full-color OLED on silicon microdisplay

    NASA Astrophysics Data System (ADS)

    Ghosh, Amalkumar P.

    2002-02-01

    eMagin has developed numerous enhancements to organic light emitting diode (OLED) technology, including a unique, up- emitting structure for OLED-on-silicon microdisplay devices. Recently, eMagin has fabricated full color SVGA+ resolution OLED microdisplays on silicon, with over 1.5 million color elements. The display is based on white light emission from OLED followed by LCD-type red, green and blue color filters. The color filters are patterned directly on OLED devices following suitable thin film encapsulation and the drive circuits are built directly on single crystal silicon. The resultant color OLED technology, with hits high efficiency, high brightness, and low power consumption, is ideally suited for near to the eye applications such as wearable PCS, wireless Internet applications and mobile phone, portable DVD viewers, digital cameras and other emerging applications.

  13. Series connected OLED structure and fabrication method

    SciTech Connect

    Foust, Donald Franklin; Balch, Ernest Wayne; Duggal, Anil Raj; Heller, Christian Maria; Guida, Renato; Nealon, William Francis; Faircloth, Tami Janene

    2006-05-23

    A light emitting device comprises a plurality of organic light emitting diode (OLED) modules. The OLED modules are arranged into a series group where the individual OLED modules are electrically connected in series. The device is configured to be coupled to a power supply. A display is also provided. The display includes a plurality of OLED modules arranged to depict a shape selected from the group consisting of at least one letter, at least one number, at least one image, and a combination thereof.

  14. Solid State Lighting OLED Manufacturing Roundtable Summary

    SciTech Connect

    none,

    2010-03-31

    Summary of a meeting of OLED experts to develop proposed priority tasks for the Manufacturing R&D initiative, including task descriptions, discussion points, recommendations, and presentation highlights.

  15. Highly efficient white OLEDs for lighting applications

    NASA Astrophysics Data System (ADS)

    Murano, Sven; Burghart, Markus; Birnstock, Jan; Wellmann, Philipp; Vehse, Martin; Werner, Ansgar; Canzler, Tobias; Stübinger, Thomas; He, Gufeng; Pfeiffer, Martin; Boerner, Herbert

    2005-10-01

    The use of organic light-emitting diodes (OLEDs) for large area general lighting purposes is gaining increasing interest during the recent years. Especially small molecule based OLEDs have already shown their potential for future applications. For white light emission OLEDs, power efficiencies exceeding that of incandescent bulbs could already be demonstrated, however additional improvements are needed to further mature the technology allowing for commercial applications as general purpose illuminating sources. Ultimately the efficiencies of fluorescent tubes should be reached or even excelled, a goal which could already be achieved in the past for green OLEDs.1 In this publication the authors will present highly efficient white OLEDs based on an intentional doping of the charge carrier transport layers and the usage of different state of the art emission principles. This presentation will compare white PIN-OLEDs based on phosphorescent emitters, fluorescent emitters and stacked OLEDs. It will be demonstrated that the reduction of the operating voltage by the use of intentionally doped transport layers leads to very high power efficiencies for white OLEDs, demonstrating power efficiencies of well above 20 lm/W @ 1000 cd/m2. The color rendering properties of the emitted light is very high and CRIs between 85 and 95 are achieved, therefore the requirements for standard applications in the field of lighting applications could be clearly fulfilled. The color coordinates of the light emission can be tuned within a wide range through the implementation of minor structural changes.

  16. Recent progress in flexible OLED displays

    NASA Astrophysics Data System (ADS)

    Hack, Michael G.; Weaver, Michael S.; Mahon, Janice K.; Brown, Julie J.

    2001-09-01

    Organic light emitting device (OLED) technology has recently been shown to demonstrate excellent performance and cost characteristics for use in numerous flat panel display (FPD) applications. OLED displays emit bright, colorful light with excellent power efficiency, wide viewing angle and video response rates. OLEDs are also demonstrating the requisite environmental robustness for a wide variety of applications. OLED technology is also the first FPD technology with the potential to be highly functional and durable in a flexible format. The use of plastic and other flexible substrate materials offers numerous advantages over commonly used glass substrates, including impact resistance, light weight, thinness and conformability. Currently, OLED displays are being fabricated on rigid substrates, such as glass or silicon wafers. At Universal Display Corporation (UDC), we are developing a new class of flexible OLED displays (FOLEDs). These displays also have extremely low power consumption through the use of electrophosphorescent doped OLEDs. To commercialize FOLED technology, a number of technical issues related to packaging and display processing on flexible substrates need to be addressed. In this paper, we report on our recent results to demonstrate the key technologies that enable the manufacture of power efficient, long-life flexible OLED displays for commercial and military applications.

  17. Using prismatic microstructured films for image blending in OLEDS

    DOEpatents

    Haenichen, Lukas [Anspach, DE; Pschenitzka, Florian [San Francisco, CA

    2009-09-08

    An apparatus such as a light source is disclosed which has an OLED device and a microstructured film disposed on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The microstructured film contains features which diffuse light emitted by said OLED device and increase the luminance of the device.

  18. Driving platform for OLED lighting investigations

    NASA Astrophysics Data System (ADS)

    Vogel, Uwe; Elgner, Andreas; Kreye, Daniel; Amelung, Jörg; Scholles, Michael

    2006-08-01

    OLED technology may be excellently suitable for lighting applications by combining high efficiency, cost effective manufacturing and the use of low cost materials. Certain issues remain to be solved so far, including OLED brightness, color, lifetime, large area uniformity and encapsulation. Another aspect, that might be capable in addressing some of the mentioned issues, is OLED lighting electrical driving. We report on the design of a driving platform for OLED lighting test panels or substrates. It is intended for being a test environment for lighting substrates as well as demonstration/presentation environment. It is based on a 128-channel passive-matrix driver/controller ASIC OC2. Its key component is an MSP430-compatible 16-bit micro-controller core including embedded Flash memory (program), EEPROM (parameter), and RAM (data memory). A significant feature of the device is an electronic approach for improving the lifetime/uniformity behavior of connected OLED. The embedded micro-controller is the key to the high versatility of OC2, since by firmware modification it can be adapted to various applications and conditions. Here its application for an OLED lighting driving platform is presented. Major features of this platform are PC-control mode (via USB interface), stand-alone mode (no external control necessary, just power supply), on-board OLED panel parameter storage, flat geometry of OLED lighting panel carrier (board), AC and DC driving regimes, adjustable reverse voltage, dedicated user SW (PC/Windows-based), sub-tile patterning and single sub-tile control, combination of multiple channels for increasing driving current. This publication contains results of the project "High Brightness OLEDs for ICT & Next Generation Lighting Applications" (OLLA), funded by the European Commission.

  19. OleD Loki as a Catalyst for Tertiary Amine and Hydroxamate Glycosylation.

    PubMed

    Hughes, Ryan R; Shaaban, Khaled A; Zhang, Jianjun; Cao, Hongnan; Phillips, George N; Thorson, Jon S

    2017-02-16

    We describe the ability of an engineered glycosyltransferase (OleD Loki) to catalyze the N-glycosylation of tertiary-amine-containing drugs and trichostatin hydroxamate glycosyl ester formation. As such, this study highlights the first bacterial model catalyst for tertiary-amine N-glycosylation and further expands the substrate scope and synthetic potential of engineered OleDs. In addition, this work could open the door to the discovery of similar capabilities among other permissive bacterial glycosyltransferases. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Host compounds for red phosphorescent OLEDs

    DOEpatents

    Xia, Chuanjun; Cheon, Kwang -Ohk

    2015-08-25

    Novel compounds containing a triphenylene moiety linked to an .alpha..beta. connected binaphthyl ring system are provided. These compounds have surprisingly good solubility in organic solvents and are useful as host compounds in red phosphorescent OLEDs.

  1. OLED microdisplay design and materials

    NASA Astrophysics Data System (ADS)

    Wacyk, Ihor; Prache, Olivier; Ali, Tariq; Khayrullin, Ilyas; Ghosh, Amalkumar

    2010-04-01

    AMOLED microdisplays from eMagin Corporation are finding growing acceptance within the military display market as a result of their excellent power efficiency, wide operating temperature range, small size and weight, good system flexibility, and ease of use. The latest designs have also demonstrated improved optical performance including better uniformity, contrast, MTF, and color gamut. eMagin's largest format display is currently the SXGA design, which includes features such as a 30-bit wide RGB digital interface, automatic luminance regulation from -45 to +70°C, variable gamma control, and a dynamic range exceeding 50:000 to 1. This paper will highlight the benefits of eMagin's latest microdisplay designs and review the roadmap for next generation devices. The ongoing development of reduced size pixels and larger format displays (up to WUXGA) as well as new OLED device architecture (e.g. high-brightness yellow) will be discussed. Approaches being explored for improved performance in next generation designs such as lowpower serial interfaces, high frame rate operation, and new operational modes for reduction of motion artifacts will also be described. These developments should continue to enhance the appeal of AMOLED microdisplays for a broad spectrum of near-to-the-eye applications such as night vision, simulation and training, situational awareness, augmented reality, medical imaging, and mobile video entertainment and gaming.

  2. Blue-hazard-free Candlelight OLED.

    PubMed

    Jou, Jwo-Huei; Singh, Meenu; Su, Yu-Ting; Liu, Shih-Hao; He, Zhe-Kai

    2017-03-19

    A candlelight-style organic light emitting diode (OLED) is a human-friendly type of lighting because it is blue-hazard-free and has a low correlated color temperature (CCT) illumination. The low CCT lighting is deprived of high-energy blue radiation, and it can be used for a longer duration before causing retinal damage. This work presents the comprehensive protocols for the fabrication of blue-hazard-free candlelight OLEDs. The emission spectrum of the OLED was characterized by the maximum exposure time limit of the retina and the melatonin suppression sensitivity. The devices can be fabricated using dry and wet processes. The dry-processed OLED resulted in a CCT of 1,940 K and exhibited a maximum retinal exposure limit of 1,287 s at a brightness of 500 lx. It showed 2.61% melatonin suppression sensitivity relative to 480 nm blue light. The wet-processed OLED, where the spin coating is used to deposit hole injection, hole transport, and emissive layers, making fabrication fast and economical, produced a CCT of 1,922 K and showed a maximum retinal exposure limit of 7,092 at a brightness of 500 lx. The achieved relative melatonin suppression sensitivity of 1.05% is 86% and 96% less than that of the light emitting diode (LED) and compact fluorescent lamp (CFL), respectively. Wet-processed blue-hazard-free candlelight OLED exhibited a power efficiency of 30 lm/W, which is 2 times that of the incandescent bulb and 300 times that of the candle.

  3. Active Matrix OLED Test Report

    NASA Technical Reports Server (NTRS)

    Salazar, George

    2013-01-01

    This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits

  4. Novel technologies for commercialized 55-inch WRGB OLED TV

    NASA Astrophysics Data System (ADS)

    Tak, Yoon-Heung; Han, Chang-Wook; Kim, Hyo-Seok; Kim, Bong-Chul; Kim, Jong-Woo; Kim, Tae-Seung; Kim, Bum-Sik; Oh, Chang-Ho; Cha, Su-Yeol; Ahn, Byung-Chul

    2013-09-01

    World's first commercialized 55-inch WRGB OLED TV has been developed and launched recently. Large-sized OLED displays require novel technologies to realize mass production. We will introduce commercialized 55-inch WRGB OLED TV and its novel technologies including oxide TFT, WOLED, solid phase encapsulation, and compensation technologies.

  5. High Efficiency, Illumination Quality OLEDs for Lighting

    SciTech Connect

    Joseph Shiang; James Cella; Kelly Chichak; Anil Duggal; Kevin Janora; Chris Heller; Gautam Parthasarathy; Jeffery Youmans; Joseph Shiang

    2008-03-31

    The goal of the program was to demonstrate a 45 lumen per watt white light device based upon the use of multiple emission colors through the use of solution processing. This performance level is a dramatic extension of the team's previous 15 LPW large area illumination device. The fundamental material system was based upon commercial polymer materials. The team was largely able to achieve these goals, and was able to deliver to DOE a 90 lumen illumination source that had an average performance of 34 LPW a 1000 cd/m{sup 2} with peak performances near 40LPW. The average color temperature is 3200K and the calculated CRI 85. The device operated at a brightness of approximately 1000cd/m{sup 2}. The use of multiple emission colors particularly red and blue, provided additional degrees of design flexibility in achieving white light, but also required the use of a multilayered structure to separate the different recombination zones and prevent interconversion of blue emission to red emission. The use of commercial materials had the advantage that improvements by the chemical manufacturers in charge transport efficiency, operating life and material purity could be rapidly incorporated without the expenditure of additional effort. The program was designed to take maximum advantage of the known characteristics of these material and proceeded in seven steps. (1) Identify the most promising materials, (2) assemble them into multi-layer structures to control excitation and transport within the OLED, (3) identify materials development needs that would optimize performance within multilayer structures, (4) build a prototype that demonstrates the potential entitlement of the novel multilayer OLED architecture (5) integrate all of the developments to find the single best materials set to implement the novel multilayer architecture, (6) further optimize the best materials set, (7) make a large area high illumination quality white OLED. A photo of the final deliverable is shown. In

  6. Assessment of OLED displays for vision research

    PubMed Central

    Cooper, Emily A.; Jiang, Haomiao; Vildavski, Vladimir; Farrell, Joyce E.; Norcia, Anthony M.

    2013-01-01

    Vision researchers rely on visual display technology for the presentation of stimuli to human and nonhuman observers. Verifying that the desired and displayed visual patterns match along dimensions such as luminance, spectrum, and spatial and temporal frequency is an essential part of developing controlled experiments. With cathode-ray tubes (CRTs) becoming virtually unavailable on the commercial market, it is useful to determine the characteristics of newly available displays based on organic light emitting diode (OLED) panels to determine how well they may serve to produce visual stimuli. This report describes a series of measurements summarizing the properties of images displayed on two commercially available OLED displays: the Sony Trimaster EL BVM-F250 and PVM-2541. The results show that the OLED displays have large contrast ratios, wide color gamuts, and precise, well-behaved temporal responses. Correct adjustment of the settings on both models produced luminance nonlinearities that were well predicted by a power function (“gamma correction”). Both displays have adjustable pixel independence and can be set to have little to no spatial pixel interactions. OLED displays appear to be a suitable, or even preferable, option for many vision research applications. PMID:24155345

  7. Assessment of OLED displays for vision research.

    PubMed

    Cooper, Emily A; Jiang, Haomiao; Vildavski, Vladimir; Farrell, Joyce E; Norcia, Anthony M

    2013-10-23

    Vision researchers rely on visual display technology for the presentation of stimuli to human and nonhuman observers. Verifying that the desired and displayed visual patterns match along dimensions such as luminance, spectrum, and spatial and temporal frequency is an essential part of developing controlled experiments. With cathode-ray tubes (CRTs) becoming virtually unavailable on the commercial market, it is useful to determine the characteristics of newly available displays based on organic light emitting diode (OLED) panels to determine how well they may serve to produce visual stimuli. This report describes a series of measurements summarizing the properties of images displayed on two commercially available OLED displays: the Sony Trimaster EL BVM-F250 and PVM-2541. The results show that the OLED displays have large contrast ratios, wide color gamuts, and precise, well-behaved temporal responses. Correct adjustment of the settings on both models produced luminance nonlinearities that were well predicted by a power function ("gamma correction"). Both displays have adjustable pixel independence and can be set to have little to no spatial pixel interactions. OLED displays appear to be a suitable, or even preferable, option for many vision research applications.

  8. An electron transporting blue emitter for OLED

    NASA Astrophysics Data System (ADS)

    Qi, Boyuan; Luo, Jiaxiu; Li, Suyue; Xiao, Lixin; Sun, Wenfang; Chen, Zhijian; Qu, Bo; Gong, Qihuang

    2010-11-01

    After the premier commercialization of OLED in 1997, OLED has been considered as the candidate for the next generation of flat panel display. In comparison to liquid crystal display (LCD) and plasma display panel (PDP), OLED exhibits promising merits for display, e.g., flexible, printable, micro-buildable and multiple designable. Although many efforts have been made on electroluminescent (EL) materials and devices, obtaining highly efficient and pure blue light is still a great challenge. In order to improve the emission efficiency and purity of the blue emission, a new bipolar blue light emitter, 2,7-di(2,2':6',2"-terpyridine)- 2,7-diethynyl-9,9-dioctyl-9H-fluorene (TPEF), was designed and synthesized. A blue OLED was obtained with the configuration of ITO/PEDOT/PVK:CBP:TPEF/LiF/Al. The device exhibits a turn-on voltage of 9 V and a maximum brightness of 12 cd/m2 at 15 V. The device gives a deep blue emission located at 420 nm with the Commission Internationale de l'Eclairage (CIE) coordinates of (0.17, 0.10). We also use TPEF as electron transporting material in the device of ITO/PPV/TPEF/LiF/Al, the turn-on voltage is 3 V. It is proved the current in the device was enhanced indeed by using the new material.

  9. Highly efficient fully transparent inverted OLEDs

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

    2007-09-01

    One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

  10. OLED lightings with optical feedback for luminance difference compensation

    NASA Astrophysics Data System (ADS)

    Shin, D. K.; Park, J. W.

    2013-12-01

    We have employed an optical feedback circuit in an organic light-emitting diode (OLED) lighting system to ensure uniform light output across large-area OLED lighting tiles. In a lighting system with several large-area OLED lighting tiles involved, the panel aging (luminance decrease) may appear differently in each, resulting in a falling-off in lighting quality. To tackle this, light output from each OLED tile is monitored by the optical feedback circuit that consists of a photodetector, I-V converter, 10-bit analogue-digital converter (ADC), and comparator. A photodetector mounted on a glass side generates a feedback signal (current) by detecting side-emitting OLED light. To monitor bottom-emitting output light by detecting side-emitting OLED light, a mapping table between the ADC value and the luminance of bottom emission has been established. If the ADC value is lower or higher than the reference one corresponding to the target luminance of OLED tiles, a micro controller unit adjusts the pulse width modulation used for the control of the power supplied to OLED tiles in such a way that the ADC value obtained from optical feedback is the same as the reference one. As a result, the target luminance of each individual OLED tile is kept unchanged. With the optical feedback circuit included in the lighting system, we have observed less than 2% difference in relative intensity of neighboring OLED tiles.

  11. Black perception in a transparent OLED display.

    PubMed

    Kim, Hyosun; Seo, Young-Jun; Yang, Byungchoon; Chu, Hye Yong

    2017-02-20

    Black perception (perceived blackness of gray 0) of transparent OLED displays was studied in this paper. In pre-test, maximum luminances of acceptable black level under various surround conditions were found in a non-transparent display. In the first experiment, the luminance of a transparent patch was compared with that of an opaque one in order to find the effect of transparency on black perception. As a result, participants perceived the transparent patch darker than the opaque one even when the two were in similar luminance levels, which we termed as the "Transparency Effect." In the second experiment, the perceived brightness of gray 0 with various background brightness conditions was investigated to observe the effect of induced black perception. Most participants perceived the luminance of gray 0 darker with brighter background luminance, but some did not. It might result from transparency of gray 0 which had a role as a window presenting the area overlapped with a transparent OLED display.

  12. OLES : Online Laboratory for Environmental Sciences

    NASA Astrophysics Data System (ADS)

    Anquetin, Sandrine; Beaufil, Xavier; Chaffard, Véronique; Juen, Patrick

    2015-04-01

    One of the major scientific challenges in the 21st century is to improve our understanding on the evolution of the water cycle associated with the climate variability. Main issues concern the prediction of i) the water resource and the access to drinkable water and ii) the extreme events, both droughts and floods. Observation strategies covering a wide range of space and time scales must therefore be set up, while continuing advanced research on the involved mechanisms and developing integrated modeling approaches. Within this general context, the present work relies on three natural observatories, located in West Africa, Worldwide Glaciers, and in Mediterranean region, managed at LTHE (Laboratoire d'étude des Transferts en Hydrologie et Environnement; Grenoble, France) and gathered at OSUG (Observatoire des Sciences de l'Univers; Grenoble, France). Their scientific objectives aim at improving the understanding of the water cycle functioning, providing water and mass balances for multi-scale basin sizes, and evaluating the hydrological impacts of the evolving climate. Water cycle variables (precipitation; soil moisture; snow cover; discharge; air and river temperatures; suspended material; etc …) are observed and recorded in 3 different databases built under specific technical constraints linked to the respective partnerships of the natural observatories. Each of the observatories has its own database, and modeling tools were developed separately leading to important efforts often duplicated. Therefore, there was a need to build an integrated cyber-infrastructure to provide access to data, and to shared tools and models that enable the understanding of the water cycle. This is the project called OLES, for Online Laboratory for Environmental Sciences. Focused on the understanding of the water cycle under contrasted climates, OLES facilitates the work of the scientific community and then, help interactions between the research community and water agencies or

  13. Status and potential for phosphorescent OLED technology

    NASA Astrophysics Data System (ADS)

    Hack, M.; Weaver, M. S.; Adamovich, V.; Kwong, R. C.; Lu, M. H.; Brown, J. J.

    2005-07-01

    As organic light emitting device (OLED) technology is building up momentum in the commercial marketplace, phosphorescent OLEDs (PHOLEDsTM) are proving themselves to be an ideal display medium for a wide range of product applications: from small mobile displays to large area TVs. As part of this work we continue to advance PHOLED technology by new materials design and device architectures. For example a green PHOLED with 4.3 V, 70 cd/A, 50 lm/W and > 10,000 hours lifetime at 1,000 cd/m2 is reported. PHOLEDs enable very low power consumption displays with low display operating temperatures, and can be deposited by a range of different deposition techniques. Along with state-of-the-art device performance we report results on the ruggedness of PHOLED materials in high volume manufacturing environments.

  14. Optimization of light extraction from OLEDs.

    PubMed

    Cui, Moxi; Urbach, H Paul; de Boer, Dick K G

    2007-04-16

    In recent years, many methods were developed to improve the efficiency of an OLED. In this paper, we investigate the effects of some main factors contributing to the extraction efficiency. These factors include the polarization of the source, the distance between the source and the metal, and the thickness of the layers. We will also discuss the effect of periodic patterns such as a grating structure.

  15. Multifunction Habitat Workstation/OLED Development

    NASA Technical Reports Server (NTRS)

    Schumacher, Shawn; Salazar, George; Schmidt, Oron

    2013-01-01

    This paper gives a general outline of both a multifunction habitat workstation and the research put into an Organic Light Emitting Diode (OLED) device. It first covers the tests that the OLED device will go through to become flight ready along with reasoning. Guidelines for building an apparatus to house the display and its components are given next, with the build of such following. The three tests the OLED goes through are presented (EMI, Thermal/Vac, Radiation) along with the data recovered. The second project of a multifunction workstation is then discussed in the same pattern. Reasoning for building such a workstation with telepresence in mind is offered. Build guidelines are presented first, with the build timeline following. Building the workstation will then be shown in great detail along with accompanying photos. Once the workstation has been discussed, the versatility of its functions are given. The paper concludes with future views and concepts that can added when the time or technology presents itself.

  16. Triarylborane-Based Materials for OLED Applications.

    PubMed

    Turkoglu, Gulsen; Cinar, M Emin; Ozturk, Turan

    2017-09-13

    Multidisciplinary research on organic fluorescent molecules has been attracting great interest owing to their potential applications in biomedical and material sciences. In recent years, electron deficient systems have been increasingly incorporated into fluorescent materials. Triarylboranes with the empty p orbital of their boron centres are electron deficient and can be used as strong electron acceptors in conjugated organic fluorescent materials. Moreover, their applications in optoelectronic devices, energy harvesting materials and anion sensing, due to their natural Lewis acidity and remarkable solid-state fluorescence properties, have also been investigated. Furthermore, fluorescent triarylborane-based materials have been commonly utilized as emitters and electron transporters in organic light emitting diode (OLED) applications. In this review, triarylborane-based small molecules and polymers will be surveyed, covering their structure-property relationships, intramolecular charge transfer properties and solid-state fluorescence quantum yields as functional emissive materials in OLEDs. Also, the importance of the boron atom in triarylborane compounds is emphasized to address the key issues of both fluorescent emitters and their host materials for the construction of high-performance OLEDs.

  17. Update of status of OLED technology

    NASA Astrophysics Data System (ADS)

    Saini, Gurdial S.

    1999-08-01

    Flat-panel displays are basically of two types: light valve (needs an external source of light) and emissive type (generates light at the display surface). The light emitting diode (LED) display is of the emissive type. The inorganic LED displays have been in use for more than 25 years in one form or the other. Because of certain limitations of inorganic materials (such as luminous efficiency and color), LED applications have been limited. The recent discovery (over the past 15 years) of polymer and organic materials has changed LED prospects. It now may become possible to make LED displays that are inexpensive, bright, low-power, large size, and at the same time provide full color. If present research objectives are met, LEDs, especially organic LEDs (OLEDs), may have the potential to revolutionize a certain segment of flat- panel display market. This paper discusses various types of OLED technologies with particular reference to Small Molecule and Conjugated Polymer displays. Some unique versions of these displays such as transparent displays and flexible displays will also be discussed. A part of the discussion will be devoted to various driver circuitry and full color generation schemes. A comprehensive list of various research efforts in OLED technology all over the world will be presented with their differentiating features. The strength of the underlying technology and the challenges facing these types of displays will be discussed.

  18. A Novel Lighting OLED Panel Design.

    PubMed

    Zhang, Enyang; Xia, Weigao; Yan, Xiaojian

    2016-11-25

    A novel OLED (organic light emitting diode) lighting panel, which uses a special layout design, can reduce the photolithography cycles and process costs and is more reliable. It only needs two steps of photolithography cycles, which include an ITO (InSnO compound transparent oxide) pattern and insulator pattern. There is no need for the metal bus pattern of the ordinary design. The OLED device structure is a type of red-green-blue (RGB)-stacked emitting layer that has a good color index and greater adjustability, which improves the performance of the device. This novel design has the same equipment and material requirement compared to the ordinary design, and it is very beneficial in terms of high volume and low-cost production. It uses a hyper driving method because the entire OLED lighting panel is divided into many sub-emitting units; if one of the sub-emitting units is burned out, it has no effect on the adjacent sub-emitting unit, so the reliability is markedly better than the ordinary design.

  19. High Efficient OLEDs and Their Application to Lighting

    NASA Astrophysics Data System (ADS)

    Komoda, Takuya; Ide, Nobuhiro; Kido, Junji

    Organic Light Emitting Diode (OLED) is one of the strongest candidates for the next generation solid state lighting alternative to conventional incandescent bulbs and fluorescent lamps. There are still a lot of issues to overcome in order to commercialize OLED lighting, but a number of elemental technologies indispensable for OLED lighting such as high efficiency, long lifetime at high luminance and large area uniform emission have been developed.

  20. Steerable patterned OLED backlight for autostereoscopic display application

    NASA Astrophysics Data System (ADS)

    Vogel, Uwe; Fehse, Karsten; Wartenberg, Philipp; Knobbe, Jens; Scholles, Michael; Richter, Bernd; Hild, Olaf

    2015-09-01

    OLED can be applied as highly efficient and high-resolution patternable illumination source for controllable and steerable backlights, e.g., for use in autostereoscopic displays. To evaluate technology and approach a 3.5" 3D QVGA display prototype has been developed and combines several achievements: large-area OLED backlight, highly-efficient and fast-response OLED top-emitter, striped patterned backlight, individual electronic driving for adaptive backlight control and 3D mobile display application.

  1. OLED emission zone measurement with high accuracy

    NASA Astrophysics Data System (ADS)

    Danz, N.; MacCiarnain, R.; Michaelis, D.; Wehlus, T.; Rausch, A. F.; Wächter, C. A.; Reusch, T. C. G.

    2013-09-01

    Highly efficient state of the art organic light-emitting diodes (OLED) comprise thin emitting layers with thicknesses in the order of 10 nm. The spatial distribution of the photon generation rate, i.e. the profile of the emission zone, inside these layers is of interest for both device efficiency analysis and characterization of charge recombination processes. It can be accessed experimentally by reverse simulation of far-field emission pattern measurements. Such a far-field pattern is the sum of individual emission patterns associated with the corresponding positions inside the active layer. Based on rigorous electromagnetic theory the relation between far-field pattern and emission zone is modeled as a linear problem. This enables a mathematical analysis to be applied to the cases of single and double emitting layers in the OLED stack as well as to pattern measurements in air or inside the substrate. From the results, guidelines for optimum emitter - cathode separation and for selecting the best experimental approach are obtained. Limits for the maximum spatial resolution can be derived.

  2. Organic light emitting diodes (OLEDS) and OLED-based structurally integrated optical sensors

    SciTech Connect

    Cai, Yuankun

    2010-01-01

    General introduction to OLED basics and OLED-based structurally integrated sensors was provided in chapter 1 and chapter 2. As discussed in chapter 3, OLEDs were developed or improved using novel engineering methods for better charge injection (increased by over 1 order of magnitude) and efficiency. As the excitation sources, these OLEDs have preferred characteristics for sensor applications, including narrowed emission, emission at desired wavelength, and enhanced output for reduced EL background, higher absorption and improved device lifetime. In addition to OLEDs with desired performance, sensor integration requires oxidase immobilization with the sensor film for O2-based biological and chemical sensing. Nanoparticles such as ZnO have large surface area and high isoelectric point (~9.5), which favors enzyme immobilization via physical adsorption as well as Coulombic bonding. In chapter 4, it was demonstrated that ZnO could be used for this purpose, although future work is needed to further bond the ZnO to the sensor film. In chapter 5, single unit sensor was extended to multianalyte parallel sensing based on an OLED platform, which is compact and integrated with silicon photodiodes and electronics. Lactate and glucose were simultaneously monitored with a low limit of detection 0.02 mM, fast response time (~1 minute) and dynamic range from 0-8.6 ppm of dissolved oxygen. As discovered in previous work, the dynamic range covers 0-100% gas phase O2 or 0-40 ppm dissolved oxygen at room temperature. PL decay curve, which is used to extract the decay time, is usually not a simple exponential at high O2 concentration, which indicates that O2 is not equally accessible for different luminescent sites. This creates a challenge for data analysis, which however was successfully processed by stretched exponential as shown in chapter 6. This also provides an insight about the distribution of O2:dye collisional quenching

  3. Industrialization of OLEDs for Lighting Applications and Displays

    NASA Astrophysics Data System (ADS)

    Brunner, Klemens

    2005-03-01

    Organic light emitting diodes (OLEDs) are an extremely versatile technology that can be tailored to specific applications. The flexibility and adaptability of OLED technology is a result of the variety of material systems and fabrication technologies that can be applied. In this contribution we investigate and compare several material systems and fabrication technologies from an application point of view. Applications without the need of micro-scale structuring open a new window of opportunity for evaporated small molecules. Small molecular OLEDs have the potential for high efficiencies at high brightness rendering them ideal for lighting applications . The first part of our contribution will establish the boundary conditions for lighting applications and we will introduces the current status of our industrialization program for OLEDs for lighting and present our perspective of the OLED lighting market. In the second part of the contribution we will focus on alternative OLED technologies that offer interesting perspectives for industrial fabrication. The light-emitting electrochemical cell (LEC) is a type of organic electroluminescent device that has all the attractive features of the OLED but does not have the drawbacks of reactive cathodes and thin active layers. The crucial difference with OLEDs is that the active layer of a LEC contains mobile ions. This results in two very important advantages for large-area lighting applications compared with traditional OLEDs: (i) thick electroactive layers (ii) and matching of the work function of the electrodes with the energy levels of the electroluminescent material is not required. This means that non-reactive metals such as Ag or Au can be used instead of e.g. Ba. We have studied several types of LECs with the aim to assess the above-mentioned benefits for large-area lighting . Finally to show the immense spectrum of production methods for OLEDs we will conclude the contribution with a manufacturing technique for

  4. High-performance OLEDs and their application to lighting

    NASA Astrophysics Data System (ADS)

    Ide, Nobuhiro; Tsuji, Hiroya; Ito, Norihiro; Sasaki, Hiroyuki; Nishimori, Taisuke; Kuzuoka, Yoshikazu; Fujihara, Koki; Miyai, Takao; Komoda, Takuya

    2008-08-01

    Organic light emitting diodes (OLED) are expected to be used in next generation solid state lighting sources serving as an alternative to conventional incandescent bulbs and fluorescent lamps. OLEDs will provide the environmental benefits of possible considerable energy savings and elimination of mercury, as well as some other advantages such as thin flat shape, planar emission, and no UV emission. Recently, important properties of OLEDs such as efficiency and lifetime have been greatly improved. Additionally, for lighting applications, a high color rendering index (CRI) at the desired CIE chromaticity coordinates, high luminance and large area uniform emission, and high stability over long time operation are also required. In this paper, we describe the development and performance of our high CRI OLEDs: the conventional OLED with multiple emissive layers and the multi-unit OLED with only two emissive units (a fluorescent blue emissive unit and a phosphorescent green / red emissive unit). Related technologies for OLED lighting to obtain uniform emission at high luminance in large areas are also described.

  5. Luminance uniformity study of OLED lighting panels depending on OLED device structures.

    PubMed

    Bae, Hyeong Woo; Son, Young Hoon; Kang, Byoung Yeop; Lee, Jung Min; Nam, Hyoungsik; Kwon, Jang Hyuk

    2015-11-30

    This paper describes the luminance uniformity of OLED lighting panels depending on OLED device structures of single emission layer (single-EML), 2-tandem, and 3-tandem. The luminance distribution is evaluated through the circuit simulation and the fabricated panel measurement. In the simulation results with yellow-green color panels of 30 × 80 mm2 emission area, a 3-tandem structure shows the lowest non-uniformity (1.34% at 7.5V), compared to single-EML (5.67% at 2.8V) and 2-tandem (2.78% at 5.3 V) structures at 1,000 cd/m2. The luminance non-uniformity is germane to the OLED conductance showing that the high luminance-current efficiency is of the most importance to achieve the uniform voltage and luminance distribution. In measurement, a 3-tandem structure also achieves the most uniform luminance distribution with non-uniformity of 4.1% while single EML and 2-tandem structures accomplish 9.6%, and 6.4%, respectively, at ~1,000 cd/m2. In addition, the simulation results ensure that a 3-tandem structure panel is allowed to be enlarged the panel size up to about 5,000 mm2 for lower luminance non-uniformity than 10% without any auxiliary metal electrodes.

  6. EDITORIAL: Flexible OLEDs and organic electronics Flexible OLEDs and organic electronics

    NASA Astrophysics Data System (ADS)

    Kim, Jang-Joo; Han, Min-Koo; Noh, Yong-Young

    2011-03-01

    Following the great discovery of the electrically conducting polymer, doped polyacetylene, which was honorably recognized in 2000 with the Nobel Prize in chemistry, conjugated molecules, i.e. organic semiconductors, have become an attractive class of active elements for various electronic or opto-electronic applications. Significant effort has been made in both academia and industry to investigate π-conjugated molecules for their unique electrical or opto-electrical properties over the last three decades. The discovery of electroluminescence in conjugated small molecules in 1982 and in polymers in 1989 was a major breakthrough, bringing those molecules to commercial applications within reach for the first time in (opto-)electronic devices, such as organic light-emitting diodes (OLEDs), photovoltaic cells (OPVs), and field-effect transistors (OFETs). Nowadays, we use OLED displays in everyday life in mobile devices. The potential of these devices, which have been fabricated with conjugated molecules, lies in the possibility to combine the advantages of solution processability, chemical tunability and material strength of polymers with the typical properties of plastics, to realize low-cost, large-area electronic devices on flexible substrates by solution deposition and direct-write graphic art printing techniques. The articles in the flexible OLEDs and organic electronics special issue in Semiconductor Science and Technology deal with a diversity of topics and effectively reflect the current status of research from all over the world on various organic electronic devices, including OLEDs, OPVs, and OFETs. Firstly, S Park et al describe the recent progress in thin-film encapsulation techniques for flexible AM-OLED and large-area OLED lightings, and their applications are discussed by J-W Park et al. Flexible active-matrix OLEDs on plastics require stable and flexible thin-film transistors processed at low temperature. Metal oxide thin-film transistors are proposed

  7. Integration of OLE into the TACL control system

    SciTech Connect

    B. Bowling; D. Douglas; J. Kewisch; P. Kloeppel; and G. A. Krafft

    1993-12-25

    OLE, the On-Line Envelope program, is a first-order optics code which was designed to provide fast lattice transfer functions from actual accelerator magnet and cavity control values. This paper addresses the results of a successful integration of OLE into the CEBAF control system, TACL. This marriage provides the user with the ability for obtaining real-time Twiss parameters and transfer functions which reflect the current operational state of the machine. The resultant OLE calculation provides the analytical core for many control and diagnostic functions used at CEBAF, including focusing corrections, orbit corrections, emittance measurements, and beamline analysis.

  8. Recent advances in small molecule OLED-on-silicon microdisplays

    NASA Astrophysics Data System (ADS)

    Ghosh, Amalkumar P.; Ali, Tariq A.; Khayrullin, Ilyas; Vazan, Fridrich; Prache, Olivier F.; Wacyk, Ihor

    2009-08-01

    High resolution OLED-on-silicon microdisplay technology is unique and challenging since it requires very small subpixel dimensions (~ 2-5 microns). eMagin's OLED microdisplay is based on white top emitter architecture using small molecule organic materials. The devices are fabricated using high Tg materials. The devices are hermetically sealed with vacuum deposited thin film layers. LCD-type color filters are patterned using photolithography methods to generate primary R, G, B colors. Results of recent improvements in the OLED-on-silicon microdisplay technology, with emphasis on efficiencies, lifetimes, grey scale and CIE color coordinates for SVGA and SXGA resolution microdisplays is presented.

  9. Polymer OLED White Light Development Program

    SciTech Connect

    Homer Antoniadis; Vi-En Choong; Stelios Choulis; Brian Cumpston; Rahul Gupta; Mathew Mathai; Michael Moyer; Franky So

    2005-12-19

    OSRAM Opto Semiconductors (OSRAM) successfully completed development, fabrication and characterization of the large area, polymer based white light OLED prototype at their OLED Research and Development (R&D) facility in San Jose, CA. The program, funded by the Department of Energy (DOE), consisted of three key objectives: (1) Develop new polymer materials and device architectures--in order to improve the performance of organic light emitters. (2) Develop processing techniques--in order to demonstrate and enable the manufacturing of large area, white light and color tunable, solid state light sources. (3) Develop new electronics and driving schemes for organic light sources, including color-tunable light sources. The key performance goals are listed. A world record efficiency of 25 lm/W was established for the solution processed white organic device from the significant improvements made during the project. However, the challenges to transfer this technology from an R&D level to a large tile format such as, the robustness of the device and the coating uniformity of large area panels, remain. In this regard, the purity and the blend nature of the materials are two factors that need to be addressed in future work. During the first year, OSRAM's Materials and Device group (M&D) worked closely with the major polymer material suppliers to develop the polymer emissive technology. M&D was successful in demonstrating a 7-8 lm/W white light source which was based on fluorescent materials. However, it became apparent that the major gains in efficiency could only be made if phosphorescent materials were utilized. Thus, in order to improve the performance of the resulting devices, the focus of the project shifted towards development of solution-processable phosphorescent light emitting diodes (PHOLEDs) and device architectures. The result is a higher efficiency than the outlined project milestone.

  10. Increased OLED radiative efficiency using a directive optical antenna.

    PubMed

    McDaniel, S; Blair, S

    2010-08-02

    We investigate the improvement in efficiency of organic light emitting diodes/displays (OLEDs) by embedding a typical OLED structure within a metallic patch grating resonator. A patch grating resonator is similar to the more familiar Fabry-Perot resonator, except that one mirror of the resonator is a metallic patch grating with a pitch approximately lambda /2 that reduces lateral propagation of radiative emission. FDTD simulations of the proposed structure indicate a potential 71% increase in emitted power over that of a reference OLED structure, and an additional 5% gain from adding an ITO spacer adjacent to the metallic electrode layer (for a total 76% increase). Implementation of this structure requires little to no modification of the OLED manufacturing process.

  11. Accelerated discovery of OLED materials through atomic-scale simulation

    NASA Astrophysics Data System (ADS)

    Halls, Mathew D.; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang; Kwak, H. Shaun; Mustard, Thomas J.; Gavartin, Jacob

    2016-09-01

    Organic light-emitting diode (OLED) devices are under widespread investigation to displace or complement inorganic optoelectronic devices for solid-state lighting and active displays. The materials in these devices are selected or designed according to their intrinsic and extrinsic electronic properties with concern for efficient charge injection and transport, and desired stability and light emission characteristics. The chemical design space for OLED materials is enormous and there is need for the development of computational approaches to help identify the most promising solutions for experimental development. In this work we will present examples of simulation approaches available to efficiently screen libraries of potential OLED materials; including first-principles prediction of key intrinsic properties, and classical simulation of amorphous morphology and stability. Also, an alternative to exhaustive computational screening is introduced based on a biomimetic evolutionary framework; evolving the molecular structure in the calculated OLED property design space.

  12. TOPICAL REVIEW: Organic light-emitting devices (OLEDs) and OLED-based chemical and biological sensors: an overview

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph; Shinar, Ruth

    2008-07-01

    The basic photophysics, transport properties, state of the art, and challenges in OLED science and technology, and the major developments in structurally integrated OLED-based luminescent chemical and biological sensors are reviewed briefly. The dramatic advances in OLED performance have resulted in devices with projected continuous operating lifetimes of ~2 × 105 h (~23 yr) at ~150 Cd m-2 (the typical brightness of a computer monitor or TV). Consequently, commercial products incorporating OLEDs, e.g., cell phones, MP3 players, and, most recently, OLED TVs, are rapidly proliferating. The progress in elucidating the photophysics and transport properties, occurring in tandem with the development of OLEDs, has been no less dramatic. It has resulted in a detailed understanding of the dynamics of trapped and mobile negative and positive polarons (to which the electrons and holes, respectively, relax upon injection), and of singlet and triplet excitons. It has also yielded a detailed understanding of the spin dynamics of polarons and triplet excitons, which affects their overall dynamics significantly. Despite the aforementioned progress, there are outstanding challenges in OLED science and technology, notably in improving the efficiency of the devices and their stability at high brightness (>1000 Cd m-2). One of the most recent emerging OLED-based technologies is that of structurally integrated photoluminescence-based chemical and biological sensors. This sensor platform, pioneered by the authors, yields uniquely simple and potentially very low-cost sensor (micro)arrays. The second part of this review describes the recent developments in implementing this platform for gas phase oxygen, dissolved oxygen (DO), anthrax lethal factor, and hydrazine sensors, and for a DO, glucose, lactate, and ethanol multianalyte sensor.

  13. Assessing the Regioselectivity of OleD-Catalyzed Glycosylation with a Diverse Set of Acceptors

    PubMed Central

    Zhou, Maoquan; Hamza, Adel; Zhan, Chang-Guo; Thorson, Jon S.

    2013-01-01

    To explore the acceptor regioselectivity of OleD-catalyzed glucosylation, the products of OleD-catalyzed reactions with the six structurally diverse acceptors - flavones (daidzein), isoflavones (flavopiridol), stilbenes (resveratrol), indole alkaloids (10-hydroxycamptothecin), and steroids (2-methoxyestradiol) - were determined. This study highlights the first synthesis of flavopiridol and 2-methoxyestradiol glucosides and confirms the ability of OleD to glucosylate both aromatic and aliphatic nucleophiles. In all cases, molecular dynamics simulations were consistent with the determined product distribution and suggest the potential to develop a virtual screening model to identify additional OleD substrates. PMID:23360118

  14. Assessing the regioselectivity of OleD-catalyzed glycosylation with a diverse set of acceptors.

    PubMed

    Zhou, Maoquan; Hamza, Adel; Zhan, Chang-Guo; Thorson, Jon S

    2013-02-22

    To explore the acceptor regioselectivity of OleD-catalyzed glucosylation, the products of OleD-catalyzed reactions with six structurally diverse acceptors flavones- (daidzein), isoflavones (flavopiridol), stilbenes (resveratrol), indole alkaloids (10-hydroxycamptothecin), and steroids (2-methoxyestradiol)-were determined. This study highlights the first synthesis of flavopiridol and 2-methoxyestradiol glucosides and confirms the ability of OleD to glucosylate both aromatic and aliphatic nucleophiles. In all cases, molecular dynamics simulations were consistent with the determined product distribution and suggest the potential to develop a virtual screening model to identify additional OleD substrates.

  15. Thin Film Packaging Solutions for High Efficiency OLED Lighting Products

    SciTech Connect

    2008-06-30

    The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology was characterized

  16. Analysis of current driving capability of pentacene TFTs for OLEDs

    NASA Astrophysics Data System (ADS)

    Ryu, Gi Seong; Byun, Hyun Sook; Xu, Yong Xian; Pyo, Kyung Soo; Choe, Ki Beom; Song, Chung Kun

    2005-01-01

    The flexible display and the application of Roll-To-Roll process is difficult because high temperature process of a-Si;H TFT and poly-Si TFT limited the use of plastic substrate. We proposed AMOLED using Pentacene TFT (OTFT) to fabricate flexible display. The first stage for OTFT application to OLED, we analyzed OTFT as driving device of OLED. The process performed on glass and plastic (PET) substrate that is coated ITO and PVP is used for gate insulator. The field effect mobility of the fabricated OTFT is 0.1~0.3cm2/V"sec and Ion/Ioff current ratio is 103~105. OLED is fabricated with two stories structure of TPD and Alq3, and we can observe the light at 5V by the naked eye. The wavelength of observed lights is 530nm ~550nm. We can confirm the driving of OLED due to OTFT using Test panel and observe OLED control by gate voltage of OTFT. Also, we verify designed structure and process, and make a demonstration fabricating 64 by 64 backplane based on Test panel.

  17. OLED lighting: light where it never has been before

    NASA Astrophysics Data System (ADS)

    Klein, M.; Heuser, K.; Schindler, F.; Krummacher, B.; Dobbertin, T.; Pätzold, R.; Gärditz, C.

    2007-02-01

    "Optical Technologies have conquered the world" - their economic key data showed an impressive growth in the past couple of years, and the predictions for the up-coming years keep the expectations high 1, 2. In the case of OLED (Organic Light Emitting Diode) lighting, e.g. IDTechEx is predicting a worldwide market growth from 50 million USD in 2009 to 3.3 billion USD in 2012 3. LED and OLED technology, although both being referred to as solid state lighting, are rather complementary in their characteristics. Whereas LEDs are high efficient point light sources, OLEDs cover large area, diffuse lighting applications which can follow the increased awareness for creation of personalized atmosphere. Ambience and mood lighting can be perfectly realized by the means of OLED large area illumination which will pave the way for applications that up to now could not have been realized. OLED lighting technology rests on three pillars at the same time, the basic performance like efficiency and lifetime, the unique features, and costs. These key challenges and their impact on various applications will be discussed.

  18. Fabrication of OLED Devices on Engineered Plastic Substrates

    SciTech Connect

    Graff, Gordon L.; Gross, Mark E.; Hall, Michael G.; Mast, Eric S.; Bonham, Charles C.; Martin, Peter M.; Shi, Ming-Kun; Brown, J.; Mahon, J.; Burrows, P.; Sullivan, M.

    2000-04-15

    Protective ultrabarrier coatings for displays on flexible polymeric film substrates were deposited. The ultrabarrier coatings met a number of tight performance specifications including low gas permeation, high conductivity transparent electrodes, chemical resistance, thermal stability and scratch resistance must be met. Transmission of oxygen and water vapors by native polymeric materials was sufficiently high to prohibit their use in LCD and OLED applications. A multilayer film structure with alternate layers of organic polymer and metal oxide, demonstrated oxygen and moisture permeation rates below the measurement limit of commercial instrumentation (<0.005 O2 cc/m2/day, H2O g/m2/day). This highly transparent, multilayer ultra-barrier coating, with and without ITO overocats, was deposited by roll-to-roll compatible, vacuum deposition processes. The process for vacuum evaporation of organic monomers and in-situ polymerization, was used to deposit the organic layers. This process was also used to encapsulate OLED structures on plastic, glass, and silicon. Flexible OLED devices have been successfully fabricated using these ultrabarrier substrates. Lifetimes of greater than 10,000 hours were achieved for encapsulated OLED devices. Performance of the OLED devices on plastic substrates was similar to those on glass substrates.

  19. High Quantum Efficiency OLED Lighting Systems

    SciTech Connect

    Shiang, Joseph

    2011-09-30

    The overall goal of the program was to apply improvements in light outcoupling technology to a practical large area plastic luminaire, and thus enable the product vision of an extremely thin form factor high efficiency large area light source. The target substrate was plastic and the baseline device was operating at 35 LPW at the start of the program. The target LPW of the program was a >2x improvement in the LPW efficacy and the overall amount of light to be delivered was relatively high 900 lumens. Despite the extremely difficult challenges associated with scaling up a wet solution process on plastic substrates, the program was able to make substantial progress. A small molecule wet solution process was successfully implemented on plastic substrates with almost no loss in efficiency in transitioning from the laboratory scale glass to large area plastic substrates. By transitioning to a small molecule based process, the LPW entitlement increased from 35 LPW to 60 LPW. A further 10% improvement in outcoupling efficiency was demonstrated via the use of a highly reflecting cathode, which reduced absorptive loss in the OLED device. The calculated potential improvement in some cases is even larger, ~30%, and thus there is considerable room for optimism in improving the net light coupling efficacy, provided absorptive loss mechanisms are eliminated. Further improvements are possible if scattering schemes such as the silver nanowire based hard coat structure are fully developed. The wet coating processes were successfully scaled to large area plastic substrate and resulted in the construction of a 900 lumens luminaire device.

  20. Materials and architectures for efficient harvesting of singlet and triplet excitons for white light emitting OLEDs

    SciTech Connect

    Thompson, Mark E; Forrest, Stephen

    2015-02-03

    The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

  1. HL7 with CORBA and OLE: software components for healthcare.

    PubMed

    Rishel, W

    1996-01-01

    Componentized software promises easier, more fine-grained integration of disparate software systems. Variations of the technology can help to achieve tight coupling among disparate programs on the clinical workstation or across wide area networks. HL7 members have been designing extensions to the protocol for the exchange of healthcare information using Microsoft OLE and CORBA technologies. Extensive prototyping has been performed, including the simultaneous interconnection of sixteen different vendor systems exchanging demographic data and lab results. The first release of this standard will be notable in that the specifications for OLE and CORBA will be entirely isomorphic, they will be based directly, on HL7 version 2.3, and they may easily be implemented in systems that are not written using object-oriented programming tools. As HL7 version 3 is developed on an object-oriented model of healthcare information, the same approach will be used so information about the objects may be shared using CORBA and OLE.

  2. High efficiency deep-blue and white phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Xue, Jiangeng; Eom, Sang-Hyun; Zheng, Ying; Wrzesniewski, Edward; Chopra, Neetu; Lee, Jaewon; So, Franky

    2009-08-01

    We report studies on blue and white organic light-emitting devices (OLEDs) based on the deep-blue electrophosphorescent dye iridium(III) bis(4',6'-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate (FIr6). Using high triplet energy charge transport layers and a dual-emissive-layer structure as well as the p-i-n device structure, we have achieved external quantum efficiencies of 20% and maximum power efficiency of 36 lm/W in these deep-blue OLEDs. White OLEDs with a CRI of 79 and a maximum power efficiency of 40 lm/W were also demonstrated by incorporating red and green phosphorescent dopants together with FIr6.

  3. Evaluation of OLED and edge-lit LED lighting panels

    NASA Astrophysics Data System (ADS)

    Mou, Xi; Narendran, Nadarajah; Zhu, Yiting; Freyssinier, Jean Paul

    2016-09-01

    Solid-state lighting (SSL) offers a new technology platform for lighting designers and end-users to illuminate spaces with low energy demand. Two types of SSL sources include organic light-emitting diodes (OLEDs) and light-emitting diodes (LEDs). OLED is an area light source, and its primary competing technology is the edge-lit LED panel. Generally, both of these technologies are considered similar in shape and appearance, but there is little understanding of how people perceive discomfort glare from large area light sources. The objective of this study was to evaluate discomfort glare for the two lighting technologies under similar operating conditions by gathering observers' reactions. The human factors study results showed no statistically significant difference in human response to discomfort glare between OLED and edge-lit LED panels when the two light sources produced the same lighting stimulus. This means both technologies appeared equally glary beyond a certain luminance.

  4. Recent developments in OLED-based chemical and biological sensors

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph; Zhou, Zhaoqun; Cai, Yuankun; Shinar, Ruth

    2007-09-01

    Recent developments in the structurally integrated OLED-based platform of luminescent chemical and biological sensors are reviewed. In this platform, an array of OLED pixels, which is structurally integrated with the sensing elements, is used as the photoluminescence (PL) excitation source. The structural integration is achieved by fabricating the OLED array and the sensing element on opposite sides of a common glass substrate or on two glass substrates that are attached back-to-back. As it does not require optical fibers, lens, or mirrors, it results in a uniquely simple, low-cost, and potentially rugged geometry. The recent developments on this platform include the following: (1) Enhancing the performance of gas-phase and dissolved oxygen sensors. This is achieved by (a) incorporating high-dielectric TiO II nanoparticles in the oxygen-sensitive Pt and Pd octaethylporphyrin (PtOEP and PdOEP, respectively)- doped polystyrene (PS) sensor films, and (b) embedding the oxygen-sensitive dyes in a matrix of polymer blends such as PS:polydimethylsiloxane (PDMS). (2) Developing sensor arrays for simultaneous detection of multiple serum analytes, including oxygen, glucose, lactate, and alcohol. The sensing element for each analyte consists of a PtOEP-doped PS oxygen sensor, and a solution containing the oxidase enzyme specific to the analyte. Each sensing element is coupled to two individually addressable OLED pixels and a Si photodiode photodetector (PD). (3) Enhancing the integration of the platform, whereby a PD array is also structurally integrated with the OLED array and sensing elements. This enhanced integration is achieved by fabricating an array of amorphous or nanocrystalline Si-based PDs, followed by fabrication of the OLED pixels in the gaps between these Si PDs.

  5. Silicon nanocrystal OLEDs: effect of organic capping group on performance.

    PubMed

    Mastronardi, Melanie L; Henderson, Eric J; Puzzo, Daniel P; Chang, Yilu; Wang, Zhi Bin; Helander, Michael G; Jeong, Junho; Kherani, Nazir P; Lu, Zhenghong; Ozin, Geoffrey A

    2012-12-07

    The synthesis of highly luminescent, colloidally-stable and organically-capped silicon nanocrystals (ncSi) and their incorporation into a visible wavelength organic light-emitting diode (OLED) is reported. By substituting decyl chains with aromatic allylbenzene capping ligands and size-selecting visible emitting ncSi, superior packing density, enhanced charge transport, and an improved photoluminescence absolute quantum yield of the ncSi is obtained in the active layer of an OLED. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Dielectric nanoparticles for the enhancement of OLED light extraction efficiency

    NASA Astrophysics Data System (ADS)

    Mann, Vidhi; Rastogi, Vipul

    2017-03-01

    This work reports the use of dielectric nanoparticles placed at glass substrate in the improvement of light extraction efficiency of organic light emitting diode (OLED). The nanoparticles will act as scattering medium for the light trapped in the waveguiding modes of the device. The scattering efficiency of dielectric nanoparticles has been calculated by Mie Theory. The finite difference time domain (FDTD) analysis and simulation estimate the effect of dielectric nanoparticles on the light extraction efficiency of OLED. The efficiency depends upon the diameter, interparticle separation and refractive index of dielectric nanoparticles. It is shown that the dielectric nanoparticles layer can enhance the light extraction efficiency by a factor of 1.7.

  7. Green-emitting MADF complex for OLED applications

    NASA Astrophysics Data System (ADS)

    Klimes, Kody; Zhu, Zhi-Qiang; Holloway, Sean; Li, Jian

    2016-09-01

    In this article, we demonstrated an exceptional palladium complex that exhibits both phosphorescence and delayed fluorescence for use as an efficient emitter in OLEDs. Devices employing PdN3N achieved external quantum efficiencies in excess of 22% and remarkable device operational lifetime to 90% initial luminance estimated at over 30,000 h at a practical luminance of 100 cd/m2. Further tuning of the phosphorescent and delayed fluorescent emission should have a great impact in the development of efficient and stable emitters for deep blue or white OLEDs.

  8. High Efficancy Integrated Under-Cabinet Phosphorescent OLED

    SciTech Connect

    Michael Hack

    2001-10-31

    In this two year program Universal Display Corporation (UDC) together with the University of Michigan, Teknokon, developed and delivered an energy efficient phosphorescent OLED under cabinet illumination system. Specifically the UDC team goal was in 2011 to deliver five (5) Beta level OLED under cabinet lighting fixtures each consisting of five 6-inch x 6-inch OLED lighting panels, delivering over 420 lumens, at an overall system efficacy of >60 lm/W, a CRI of >85, and a projected lifetime to 70% of initial luminance to exceed 20,000 hours. During the course of this program, the Team pursued the commercialization of these OLED based under cabinet lighting fixtures, to enable the launch of commercial OLED lighting products. The UDC team was ideally suited to develop these novel and efficient solid state lighting fixtures, having both the technical experience and commercial distribution mechanisms to leverage work performed under this contract. UDC's business strategy is to non-exclusively license its PHOLED technology to lighting manufacturers, and also supply them with our proprietary PHOLED materials. UDC is currently working with several licensees who are manufacturing OLED lighting panels using our technology. During this 2 year program, we further developed our high efficiency white Phosphorescent OLEDs from the first milestone, achieving a 80 lm/W single pixel to the final milestone, achieving an under-cabinet PHOLED lighting system that operates at 56 lm/W at 420 lumens. Each luminaire was comprised of ten 15cm x 7.5cm lighting modules mounted in outcoupling enhancement lenses and a control module. The lamps modules are connected together using either plugs or wires with plugs on each end, allowing for unlimited configurations. The lamps are driven by an OLED driver mounted in an enclosure which includes the AC plug. As a result of advancements gained under this program, the path to move OLED lighting panels from development into manufacturing has been

  9. Advances in OLED-based oxygen sensors with structurally integrated OLED, sensor film, and thin-film Si photodetector

    NASA Astrophysics Data System (ADS)

    Ghosh, Debju; Shinar, Ruth; Cai, Yuankun; Zhou, Zhaoqun; Dalal, Vikram L.; Shinar, Joseph

    2007-09-01

    Steps towards the improvement of a compact photoluminescence (PL)-based sensor array that is fully structurally integrated are described. The approach is demonstrated for oxygen sensing, which can be monitored via its effect on the PL intensity I or decay time τ of oxygen-sensitive dyes such as Pt octaethylporphryn (PtOEP) and its Pd analog (PdOEP). The integrated components include (1) an organic light emitting device (OLED) excitation source, which is an array of coumarin-doped tris(quinolinolate) Al (Alq 3) pixels, (2) the sensor film, i.e., PdOEP embedded in polystyrene, and (3) the photodetector (PD), which is a plasma-enhanced CVD-grown p-i-n or n-i-p structure, based on amorphous or nanocrystalline (Si,Ge):H. These components are fabricated on common or separate substrates that are attached back-to-back, resulting in sensors with a thickness largely determined by that of the substrates. The fully integrated oxygen sensor is demonstrated first by fabricating each of the three components on a separate substrate. The PD was placed in front of a flow cell containing the sensor film, while the OLED array was "behind" the sensor film. This design showed the expected trend in monitoring different concentration of O II via their effect on I, with improved detection sensitivity achieved by shielding the electromagnetic noise synchronous with the pulsed OLED. The detection sensitivity using the I monitoring mode is expected to further increase by reducing the OLED tail emission. The issue of the OLED background can be eliminated by monitoring the oxygen concentration via its effect on τ, where the OLED is pulsed and τ is measured while the OLED is off. Steps therefore focused also on shortening the response time of the PDs, and understanding the factors affecting their speed. Development of a sensor array, where the PD pixels are fabricated between the OLED pixels on the same side of a common substrate, is also discussed.

  10. Enhanced performance of organic light-emitting diodes (OLEDs) and OLED-based photoluminescent sensing platforms by novel microstructures and device architectures

    SciTech Connect

    Liu, Rui

    2012-01-01

    After a general introduction to OLEDs and OLED-based PL sensors, the transient emission mechanism of guest-host OLEDs is described both experimentally and theoretically. A monolithic and easy-to-apply process is demonstrated for fabricating multicolor microcavity OLEDs (that improve the sensor platform). The outcoupling issues of OLEDs at the substrate/air interface are addressed by using a microstructured polymer film resulting from a PS and polyethylene glycol (PEG) mixture. Based on the understanding of OLEDs and their improvement, research was done in order to realize integrated all organic-based O2 and pH sensors with improved signal intensity and sensitivity. The sensor design modification and optimization are summarized

  11. High performances, temperature resistant and stable OLED structures.

    PubMed

    Prat, C; Vaufrey, D; Maindron, T; Cloarec, H; Pinot, C; Haas, G

    2008-10-01

    In the present work, a particular emphasis is put on the stability of the OLED devices obtained as well as on their ability to keep their good initial performances even in a severe environment. Moreover, the operation voltage of these devices turns out to be rather low.

  12. Ole Ivar Lovaas--His Life, Merits and Legacy

    ERIC Educational Resources Information Center

    Özerk, Kamil; Vea, Gunvor Dalby; Eikeseth, Svein; Özerk, Meral

    2016-01-01

    Ole Ivar Lovaas (1927-2010) is known worldwide for his research within the field of Applied Behavior Analysis, and is probably the most influential researcher within the field of treatment of children with autism. In the first part of this biographically oriented paper, we inform the readers about his family background, childhood, elementary and…

  13. Some approaches for fabricating high-efficiency OLEDs

    NASA Astrophysics Data System (ADS)

    Jou, Jwo-Huei; Wang, Wei-Ben; Shen, Shih-Ming; Wu, Ming-Hsuan

    2009-08-01

    High-efficiency is strongly desired for organic light-emitting diodes (OLEDs) to be fully realized as the future display and lighting technology. To replace current illumination tools, such as incandescent bulbs and fluorescent tubes, for examples, OLEDs with much higher efficiency are demanded. We will present herein some approaches for fabricating high-efficiency OLEDs of blue and white emission. Besides employing highly efficient electroluminescent guests and thin device architecture, low injection barriers to carriers, high carrier-transporting character, effective carrier/exciton confinement, balanced carrier-injection, exciton generation on host, effective host-to-guest energy-transfer and improved light-coupling efficiency are essential. Amongst, the incorporation of nano-dots in emissive- and non-emissive-layers can markedly improve the device efficiency. The enhancement is especially marked as small polymeric nano-dots are incorporated into the non-emissive layers. Since the incorporation is not in the emissive layer, the efficiency improvement mechanism works for both fluorescent and phosphorescent devices. Importantly, the efficiency improvement is also a strong function of the surface charge density of the nano-dots. Regardless positively or negatively charged, the improvement becomes more pronounced as the charge density increases. Results regarding some lately achieved extraordinarily highly-efficient OLEDs containing nano-dots with high surface charge will be presented.

  14. Light extraction and customized optical distribution from plastic micro-optics integrated OLEDs

    NASA Astrophysics Data System (ADS)

    Melpignano, P.; Rotaris, G.; Biondo, V.; Sinesi, S.; Westenhöfer, S.; Gale, M. T.; Murgia, M.; Caria, S.; Zamboni, R.

    2006-04-01

    An OLED device suitable for automobile ceiling lights has been designed, fabricated and evaluated. The OLED structure is fabricated on a thin (120 µm), flexible polymer foil with integrated micro-optics to achieve customized beam shaping in the far field. A pixelated OLED structure matched to a patch-pad microlens matrix was used to convert the OLED Lambertian emission into a Gaussian-shaped illumination beam. Both refractive and diffractive microlenses were investigated. The integrated micro-optics OLED architecture reduces light losses due to waveguiding effects and effectively increases the light extraction by up to 70%.

  15. Roll-to-Roll Solution-Processible Small-Molecule OLEDs

    SciTech Connect

    Liu, Jie Jerry

    2012-07-31

    The objective of this program is to develop key knowledge and make critical connections between technologies needed to enable low-cost manufacturing of OLED lighting products. In particular, the program was intended to demonstrate the feasibility of making high performance Small-Molecule OLEDs (SM-OLED) using a roll-to-roll (R2R) wet-coating technique by addressing the following technical risks (1) Whether the wet-coating technique can provide high performance OLEDs, (2) Whether SM-OLED can be made in a R2R manner, (3) What are the requirements for coating equipment, and (4) Whether R2R OLEDs can have the same performance as the lab controls. The program has been managed and executed according to the Program Management Plan (PMP) that was first developed at the beginning of the program and further revised accordingly as the program progressed. Significant progress and risk reductions have been accomplished by the end of the program. Specific achievements include: (1) Demonstrated that wet-coating can provide OLEDs with high LPW and long lifetime; (2) Demonstrated R2R OLEDs can be as efficient as batch controls (Figure 1) (3) Developed & validated basic designs for key equipment necessary for R2R SM-OLEDs; (4) Developed know-hows & specifications on materials & ink formulations critical to wetcoating; (5) Developed key R2R processes for each OLED layer (6) Identified key materials and components such as flexible barrier substrates necessary for R2R OLEDs.

  16. Development of High Efficacy, Low Cost Phosphorescent Oled Lightning Luminaire

    SciTech Connect

    Michael Hack

    2010-07-09

    In this two year program, UDC together with Armstrong World Industries, Professor Stephen Forrest (University of Michigan) and Professor Mark Thompson (University of Southern California) planned to develop and deliver high efficiency OLED lighting luminaires as part of an integrated ceiling illumination system that exceed the Department of Energy (DOE) 2010 performance projections. Specifically the UDC team in 2010 delivered two prototype OLED ceiling illumination systems, each consisting of four individual OLED lighting panels on glass integrated into Armstrong's novel TechZone open architecture ceiling systems, at an overall system efficacy of 51 lm/W, a CRI = 85 and a projected lifetime to 70% of initial luminance to exceed 10,000 hours. This accomplishment represents a 50% increase in luminaire efficacy and a factor of two in lifetime over that outlined in the solicitation. In addition, the team has also delivered one 15cm x 15cm lighting panel fabricated on a flexible metal foil substrate, demonstrating the possibility using OLEDs in a range of form factors. During this program, our Team has pursued the commercialization of these OLED based ceiling luminaires, with a goal to launch commercial products within the next three years. We have proven that our team is ideally suited to develop these highly novel and efficient solid state lighting luminaires, having both the technical experience and commercial strategy to leverage work performed under this contract. Our calculations show that the success of our program could lead to energy savings of more than 0.5 quads or 8 MMTC (million metric tons of carbon) per year by 2016.

  17. Enhanced performance of organic light-emitting diodes (OLEDs) and OLED-based photoluminescent sensing platforms by novel microstructures and device architectures

    NASA Astrophysics Data System (ADS)

    Liu, Rui

    Organic light emitting diodes (OLEDs) have advanced dramatically since they exhibit great promise in various applications such as displays, solid-state lighting, and (bio)chemical sensing. In this dissertation, multiple approaches were employed to enhance the performance of OLEDs and OLED-based sensing platforms. Comprehensive investigations were conducted on electroluminescence (EL) spikes and tails in charge trapping guest-host OLEDs and their influence on OLED-based sensor performance. Novel microstructures and device architectures were developed to construct OLED sources with spectrally selective and enhanced emission. The peak emission wavelength of the multicolor microcavity devices with MoO3 as the HIL/spacer was tunable from 493 to 639 nm. The controlled microporous structures formed by polystyrene (PS):polyethylene glycol (PEG) was able to enhance the forward light extraction of the OLED by up to ˜60%. The combination of the PtOEP:PS:PEG sensing film coupled with the multicolor microcavity OLEDs and the appropriate OPD, and the possibility to combine time- and intensity-domain analyses have shed light on the opportunities to realize simple, compact, potentially disposable sensors for the detection of O2, pH and other (bio)chemical analytes and parameters.

  18. Position Effect Based on Anthracene Core for OLED Emitters.

    PubMed

    Kang, Hyeonmi; Shin, Hwangyu; Kim, Beomjin; Park, Jongwook

    2016-03-01

    Green-orange emitters based on anthracene core have been successfully synthesized by substitution with triphenylamine side group in the 9, 10 or 2, 6 positions. There are larger blue shifts in the UV-visible absorption and PL spectra of the synthesized 2,6-substituted derivative compared to the 9,10-substituted derivative. When the synthesized compounds were used as emitting layers in non-doped OLED devices, a related trend was observed in their optical properties. In particular, the OLED device containing the 2,6-substituted derivative was found to exhibit excellent characteristics, with maximum EL emission at 518 nm, pure green emission with CIE coordinates of (0.334, 0.604), and external quantum efficiency of 2.83%.

  19. INK-JET PRINTING OF PF6 FOR OLED APPLICATIONS

    SciTech Connect

    Burrasca, G.; Fasolino, T.; Miscioscia, R.; Nenna, G.; Vacca, P.; Villani, F.; Minarini, C.; Della Sala, D.

    2008-08-28

    In the last years there has been much interest in applying ink-jet printing (IJP) technology to the deposition of several materials for organic electronics applications, including metals, polymers and nanoparticles dispersions on flexible substrates. The aim of this work is to study the effect of ink-jet deposition of polymer films in the manufacturing of OLED devices comparing their performances to standard technologies. The ink-jet printed polymer is introduced in an hybrid structure in which other layers are deposited by vacuum thermal evaporation. The electrical and optical properties of the obtained devices are investigated.OLEDs with the same structure were fabricated by spin-coating a polymer film by the same solution used as ink. Results have been compared to the above ones to determine how the deposition method affects the device optoelectronic properties.

  20. High efficiency and stable white OLED using a single emitter

    SciTech Connect

    Li, Jian

    2016-01-18

    The ultimate objective of this project was to demonstrate an efficient and stable white OLED using a single emitter on a planar glass substrate. The focus of the project is on the development of efficient and stable square planar phosphorescent emitters and evaluation of such class of materials in the device settings. Key challenges included improving the emission efficiency of molecular dopants and excimers, controlling emission color of emitters and their excimers, and improving optical and electrical stability of emissive dopants. At the end of this research program, the PI has made enough progress to demonstrate the potential of excimer-based white OLED as a cost-effective solution for WOLED panel in the solid state lighting applications.

  1. Ink-Jet Printing of PF6 for Oled Applications

    NASA Astrophysics Data System (ADS)

    Burrasca, G.; Fasolino, T.; Miscioscia, R.; Nenna, G.; Vacca, P.; Villani, F.; Minarini, C.; Sala, D. della

    2008-08-01

    In the last years there has been much interest in applying ink-jet printing (IJP) technology to the deposition of several materials for organic electronics applications, including metals, polymers and nanoparticles dispersions on flexible substrates. The aim of this work is to study the effect of ink-jet deposition of polymer films in the manufacturing of OLED devices comparing their performances to standard technologies. The ink-jet printed polymer is introduced in an hybrid structure in which other layers are deposited by vacuum thermal evaporation. The electrical and optical properties of the obtained devices are investigated. OLEDs with the same structure were fabricated by spin-coating a polymer film by the same solution used as ink. Results have been compared to the above ones to determine how the deposition method affects the device optoelectronic properties.

  2. Novel bipolar bathophenanthroline containing hosts for highly efficient phosphorescent OLEDs.

    PubMed

    Ge, Ziyi; Hayakawa, Teruaki; Ando, Shinji; Ueda, Mitsuru; Akiike, Toshiyuki; Miyamoto, Hidetoshi; Kajita, Toru; Kakimoto, Masa-aki

    2008-02-07

    The electronic structures of eight bathophenanthroline derivatives were elucidated by DFT calculations, and four representatives of which CZBP, m-CZBP, m-TPAP, and BPABP were synthesized and employed as the hosts to afford highly efficient phosphorescent OLEDs. The calculated molecular orbital energies agree well with the experimental results, which further demonstrates that the localization of HOMO and LUMO at the respective hole- and electron-transporting moieties is desirable in bipolar molecular designs.

  3. Monolithic OLED-Microwire Devices for Ultrastrong Magnetic Resonant Excitation.

    PubMed

    Jamali, Shirin; Joshi, Gajadhar; Malissa, Hans; Lupton, John M; Boehme, Christoph

    2017-08-09

    Organic light-emitting diodes (OLEDs) make highly sensitive probes to test magnetic resonance phenomena under unconventional conditions since spin precession controls singlet-triplet transitions of electron-hole pairs, which in turn give rise to distinct recombination currents in conductivity. Electron paramagnetic resonance can therefore be detected in the absence of spin polarization. We exploit this characteristic to explore the exotic regime of ultrastrong light-matter coupling, where the Rabi frequency of a charge carrier spin is of the order of the transition frequency of the two-level system. To reach this domain, we have to lower the Zeeman splitting of the spin states, defined by the static magnetic field B0, and raise the strength of the oscillatory driving field of the resonance, B1. This is achieved by shrinking the OLED and bringing the source of resonant radio frequency (RF) radiation as close as possible to the organic semiconductor in a monolithic device structure, which incorporates an OLED fabricated directly on top of an RF microwire within one monolithic thin-film device structure. With an RF driving power in the milliwatt range applied to the microwire, the regime of bleaching and inversion of the magnetic resonance signal is reached due to the onset of the spin-Dicke effect. In this example of ultrastrong light-matter coupling, the individual resonant spin transitions of electron-hole pairs become indistinguishable with respect to the driving field, and superradiance of the magnetic dipole transitions sets in.

  4. Improvement of OLED properties with anti-reflection coatings

    NASA Astrophysics Data System (ADS)

    Liu, Chunling; Wang, Dongmei; Zhao, Lei; Jiang, Wenlong; Qin, Zhengkun; Wang, Chunwu

    2010-11-01

    An anti-reflection (AR) coating system was inserted between the anode (ITO) and the glass substrate in the red light organic electroluminescent devices (OLED) for the structure being K9/ITO/NPB (60nm)/DCJTB (0.3nm)/Alq3 (60nm)/ LiF(0.3nm)/Al. The AR film system structure was K9/TiO2/Al2O3/2-ITO, and the optical thicknesses of TiO2 and Al2O3 coatings were also quarter wave length. The results indicated that the maximum transmissivity of AR coating was by 95 %( 610nm); it increased by 8% compared with only using ITO as AR coating. The average luminance increased by about 30%, the average energy efficiency increased by about 60%, while reducing the threshold voltage of the devices. The processing is simple and high efficient, and can change AR coating structure according to the OLED device different emission wavelength, therefore, can be widely applied to the OLED devices.

  5. Extraction of internal emission characteristics from printed OLEDs

    NASA Astrophysics Data System (ADS)

    Hildner, Mark L.; Ziebarth, Jonathan M.

    2012-09-01

    Accurate optical modeling of OLED device performance is beneficial to OLED manufacturing because as materials and architectures are modified, experimental effort and resources are saved in the search for optimal structures. The success of such modeling depends crucially on model inputs, which include, along with layer thicknesses and optical constants, internal emission characteristics such as the internal emission spectrum (IES) of the emitter and the location and profile of emission in the emissive layer (EML). This presentation will describe two methods we have used to extract the internal emission characteristics of our printed bottom emitting OLEDs. The first method, which we devised and implemented with assumptions specific to our devices, is a simpler one for both modeling and data collection: we collected spectra at normal viewing angle for a series of devices with different architectures, and extracted a normalized IES common to all these devices. We will show how an emission location was obtained from this method with some simple model assumptions. In the more rigorous second method - one presented by van Mensfoort et al 1 - internal emission characteristics were extracted independently for each device: spectra at multiple angles were collected, which allowed the extraction of an individual IES and emission profile. We will compare the findings of the two methods and assess the validity of the assumptions used in the first method.

  6. Inkjet printing of photopolymerizable small molecules for OLED applications

    NASA Astrophysics Data System (ADS)

    Olivier, Simon; Derue, Lionel; Geffroy, Bernard; Ishow, Eléna; Maindron, Tony

    2015-09-01

    The elaboration of organic light-emitting diodes (OLEDs) via a solution deposition process turns out to be a cheaper alternative to the vacuum evaporation technique. However the most popular spin-coating wet deposition process mainly used in the semiconductor industry is not applicable for large mother glass substrates used in display applications. The inkjet technology addresses this drawback and appears to be a good solution to produce on a large scale wet deposited OLEDs1. This process has been commonly used for polymer deposition and only a few examples2-4 have demonstrated the possibility of depositing small molecules in functional devices. Deposition of small molecules from inkjet printing is supposed to be easier than polymers because monomers do not show polydispersity and consequently the viscosity of the solution containing the monomers, the ink, is easily controllable in production. This work aims at fabricating OLEDs composed of inkjet-printed hole-transporting molecules and a new class of fluorescent molecules that have been further UV-photopolymerized right after deposition.

  7. Recent advances in AM OLED technologies for application to aerospace and military systems

    NASA Astrophysics Data System (ADS)

    Sarma, Kalluri R.; Roush, Jerry; Chanley, Charles

    2012-06-01

    While initial AM OLED products have been introduced in the market about a decade ago, truly successful commercialization of OLEDs has started only a couple of years ago, by Samsung Mobile Display (SMD), with small high performance displays for smart phone applications. This success by Samsung has catalyzed significant interest in AM OLED technology advancement and commercialization by other display manufacturers. Currently, significant manufacturing capacity for AM OLED displays is being established by the industry to serve the growing demand for these displays. The current development in the AM OLED industry are now focused on the development and commercialization of medium size (~10") AM OLED panels for Tablet PC applications and large size (~55") panels for TV applications. This significant progress in commercialization of AM OLED technology is enabled by major advances in various enabling technologies that include TFT backplanes, OLED materials and device structures and manufacturing know-how. In this paper we will discuss these recent advances, particularly as they relate to supporting high performance applications such as aerospace and military systems, and then discuss the results of the OLED testing for aerospace applications.

  8. Modeling OLED lighting using Monte Carlo ray tracing and rigorous coupling wave analyses

    NASA Astrophysics Data System (ADS)

    Wei, An-Chi; Sze, Jyh-Rou

    2016-12-01

    Monte Carlo ray tracing and rigorous coupling wave analyses (RCWA) are linked together for modeling the lighting property of organic light-emitting diodes (OLED). The proposed method considers the thin-film effect and the whole geometrical structure of OLED instead of a single exciton, realizing a mixed-level and comprehensive model with reduced simulation complexity. According to experimental results, the proposed model has demonstrated an acceptable accuracy for the conventional planar OLED. Additionally, corrugated OLEDs are investigated for the blue spectrum enhancement. The simulations from the proposed model indicate that the reduced corrugated period or duty cycle contributes to blue-shift of the EL spectra.

  9. Polymer OLED microdisplay technology: pixel design in context

    NASA Astrophysics Data System (ADS)

    Underwood, I.; Burns, D. C.; Woodburn, R. J.

    2006-08-01

    Microdisplays are used in many applications from electronic viewfinders to rear projection television and even in non-display applications such as printers. There exist a number of microdisplay technologies based upon different materials and physical systems. We outline the various classes of microdisplay along with their suitability for certain applications. We describe an emerging microdisplay technology based on a combination of polymeric organic electroluminescent material and CMOS active-matrix backplane, making comparisons with conventional OLED display technology and other microdisplay technologies. We focus, in particular, on a novel active matrix addressing approach for the emerging technology.

  10. Stacked white OLED having separate red, green and blue sub-elements

    DOEpatents

    Forrest, Stephen; Qi, Xiangfei; Slootsky, Michael

    2015-06-23

    The present invention relates to efficient organic light emitting devices (OLEDs). More specifically, the present invention relates to white-emitting OLEDs, or WOLEDs. The devices of the present invention employ three emissive sub-elements, typically emitting red, green and blue, to sufficiently cover the visible spectrum. The sub-elements are separated by charge generating layers.

  11. Novel carbazole/fluorene hybrids: host materials for blue phosphorescent OLEDs.

    PubMed

    Shih, Ping-I; Chiang, Chih-Long; Dixit, Ajay Kumar; Chen, Ching-Kun; Yuan, Mao-Chuan; Lee, Rei-Yuen; Chen, Chin-Ti; Diau, Eric Wei-Guang; Shu, Ching-Fong

    2006-06-22

    [reaction: see text] A series of carbazole/fluorene (CBZm-Fn) hybrids were effectively synthesized through Friedel-Crafts-type substitution of the carbazole rings. These compounds were thermally and morphologically stable host materials for OLED applications. Efficient blue phosphorescent OLEDs were obtained when employing CBZ1-F2 as the host and FIrpic as the guest.

  12. Integrating Existing Applications in Hypermedia Learning Material (General Issues & Experiences with OLE Technology).

    ERIC Educational Resources Information Center

    Borst Pauwels, H. W. J.; And Others

    The integration of existing applications in hypermedia environments is a promising approach towards more flexible and user-friendly hypermedia learning materials. A hypermedia courseware editor, called HyDE (Hypermedia Document Editor) was developed using Microsoft Windows TM OLE technology. OLE (object Linking and Embedding) stands for an…

  13. Organic Light-Emitting Devices (OLEDS) and Their Optically Detected Magnetic Resonance (ODMR)

    SciTech Connect

    Li, Gang

    2003-01-01

    Organic Light-Emitting Devices (OLEDs), both small molecular and polymeric have been studied extensively since the first efficient small molecule OLED was reported by Tang and VanSlyke in 1987. Burroughes' report on conjugated polymer-based OLEDs led to another track in OLED development. These developments have resulted in full color, highly efficient (up to {approx} 20% external efficiency 60 lm/W power efficiency for green emitters), and highly bright (> 140,000 Cd/m{sup 2} DC, {approx}2,000,000 Cd/m{sup 2} AC), stable (>40,000 hr at 5 mA/cm{sup 2}) devices. OLEDs are Lambertian emitters, which intrinsically eliminates the view angle problem of liquid crystal displays (LCDs). Thus OLEDs are beginning to compete with the current dominant LCDs in information display. Numerous companies are now active in this field, including large companies such as Pioneer, Toyota, Estman Kodak, Philipps, DuPont, Samsung, Sony, Toshiba, and Osram, and small companies like Cambridge Display Technology (CDT), Universal Display Corporation (UDC), and eMagin. The first small molecular display for vehicular stereos was introduced in 1998, and polymer OLED displays have begun to appear in commercial products. Although displays are the major application for OLEDs at present, they are also candidates for nest generation solid-state lighting. In this case the light source needs to be white in most cases. Organic transistors, organic solar cells, etc. are also being developed vigorously.

  14. Stacked white OLED having separate red, green and blue sub-elements

    SciTech Connect

    Forrest, Stephen; Qi, Xiangfei; Slootsky, Michael

    2016-06-28

    The present invention relates to efficient organic light emitting devices (OLEDs). More specifically, the present invention relates to white-emitting OLEDs, or WOLEDs. The devices of the present invention employ three emissive sub-elements, typically emitting red, green and blue, to sufficiently cover the visible spectrum. The sub-elements are separated by charge generating layers.

  15. Tris-(8-hydroxyquinoline)aluminum thin film as ETL in efficient green phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Thangaraju, K.; Kim, Yun-Hi; Kwon, Soon-Ki

    2013-02-01

    Tris-(8-hydroxyquinoline)aluminum thin film as ETL in green phosphorescent OLEDs improves the device performances to a maximum of 34.2 cd/A, 11.3% with the maximum brightness of 63,150 cd/m2 and broadens the device emission in yellow-green region suitable in the white OLEDs for the lighting applications.

  16. GATEWAY Demonstrations: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    SciTech Connect

    Miller, Naomi J.

    2016-03-31

    At the offices of Aurora Lighting Design, Inc., in Grayslake, IL, the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  17. Light diffusing effects of nano and micro-structures on OLED with microcavity.

    PubMed

    Cho, Doo-Hee; Shin, Jin-Wook; Joo, Chul Woong; Lee, Jonghee; Park, Seung Koo; Moon, Jaehyun; Cho, Nam Sung; Chu, Hye Yong; Lee, Jeong-Ik

    2014-10-20

    We examined the light diffusing effects of nano and micro-structures on microcavity designed OLEDs. The results of FDTD simulations and experiments showed that the pillar shaped nano-structure was more effective than the concave micro-structure for light diffusing of microcavity OLEDs. The sharp luminance distribution of the microcavity OLED was changed to near Lambertian luminance distribution by the nano-structure, and light diffusing effects increased with the height of the nano-structure. Furthermore, the nano-structure has advantages including light extraction of the substrate mode, reproducibility of manufacturing process, and minimizing pixel blur problems in an OLED display panel. The nano-structure is a promising candidate for a light diffuser, resolving the viewing angle problems in microcavity OLEDs.

  18. Improved spatiotemporal-multiplexing super-multiview display based on planar aligned OLED microdisplays.

    PubMed

    Teng, Dongdong; Pang, Zhiyong; Zhang, Yueli; Wu, Dong; Wang, Jiahui; Liu, Lilin; Wang, Biao

    2015-08-24

    Through gating spectrum plane of multiple planar aligned OLED microdisplays by a timely sequential manner, a super-multiview (SMV) three-dimensional (3D) display based on spatiotemporal-multiplexing was developed in our previous paper. But an upper limit of the allowable sub-viewing-zones (SVZs) for an OLED microdisplay did exist in the previous system, even if microdisplays with very high frame rates could be commercially available. In this manuscript, an improved spatiotemporal-multiplexing SMV displays system is developed, which removes the above limitation through controllable fusing of light beams from adjacent OLED microdisplays. The employment of a liquid-crystal panel as the gating-aperture array allows the improved system to accommodate multiple rows of OLED microdisplays for denser SVZs. Experimentally, a prototype system is demonstrated by 24 OLED microdisplays, resulting in 120 SVZs with an interval small to 1.07mm.

  19. Near independence of OLED operating voltage on transport layer thickness

    SciTech Connect

    Swensen, James S.; Wang, Liang; Polikarpov, Evgueni; Rainbolt, James E.; Koech, Phillip K.; Cosimbescu, Lelia; Padmaperuma, Asanga B.

    2013-01-01

    We report organic light emitting devices (OLEDs) with weak drive voltage dependence on the thickness of the hole transport layer (HTL) for thicknesses up to 1150 Å using the N,N'-Bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD) and N,N'-bis(3-methyl phenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'diamine (TPD), both of which have hole mobilities in the range of 2 × 10-3 cm2V-1s-1. Lower mobility HTL materials show larger operating voltage dependence on thickness. The near independence of the operating voltage for high mobility transport material thickness was only observed when the energy barrier for charge injection into the transport material was minimized. To ensure low injection barriers, a thin film of 2-(3-(adamantan-1-yl)propyl)-3,5,6-trifluorotetracyanoquinodimethane (F3TCNQ-Adl) was cast from solution onto the ITO surface. These results indicate that thick transport layers can be integrated into OLED stacks without the need for bulk conductivity doping.

  20. Recovery Act: Low Cost Integrated Substrate for OLED Lighting Development

    SciTech Connect

    Benton, Scott; Bhandari, Abhinav

    2012-12-26

    PPG pursued the development of an integrated substrate, including the anode, external, and internal extraction layers. The objective of PPG's program was to achieve cost reductions by displacing the existing expensive borosilicate or double-side polished float glass substrates and developing alternative electrodes and scalable light extraction layer technologies through focused and short-term applied research. One of the key highlights of the project was proving the feasibility of using PPG's high transmission Solarphire® float glass as a substrate to consistently achieve organic lightemitting diode (OLED) devices with good performance and high yields. Under this program, four low-cost alternatives to the Indium Tin Oxide (ITO) anode were investigated using pilot-scale magnetron sputtered vacuum deposition (MSVD) and chemical vapor deposition (CVD) technologies. The anodes were evaluated by fabricating small and large phosphorescent organic lightemitting diode (PHOLED) devices at Universal Display Corporation (UDC). The device performance and life-times comparable to commercially available ITO anodes were demonstrated. A cost-benefit analysis was performed to down-select two anodes for further low-cost process development. Additionally, PPG developed and evaluated a number of scalable and compatible internal and external extraction layer concepts such as scattering layers on the outside of the glass substrate or between the transparent anode and the glass interface. In one external extraction layer (EEL) approach, sol-gel sprayed pyrolytic coatings were deposited using lab scale equipment by hand or automated spraying of sol-gel solutions on hot glass, followed by optimizing of scattering with minimal absorption. In another EEL approach, PPG tested large-area glass texturing by scratching a glass surface with an abrasive roller and acid etching. Efficacy enhancements of 1.27x were demonstrated using white PHOLED devices for 2.0mm substrates which are at par with

  1. Effect of thermal annealing Super Yellow emissive layer on efficiency of OLEDs.

    PubMed

    Burns, Samantha; MacLeod, Jennifer; Trang Do, Thu; Sonar, Prashant; Yambem, Soniya D

    2017-01-20

    Thermal annealing of the emissive layer of an organic light emitting diode (OLED) is a common practice for solution processable emissive layers and reported annealing temperatures varies across a wide range of temperatures. We have investigated the influence of thermal annealing of the emissive layer at different temperatures on the performance of OLEDs. Solution processed polymer Super Yellow emissive layers were annealed at different temperatures and their performances were compared against OLEDs with a non-annealed emissive layer. We found a significant difference in the efficiency of OLEDs with different annealing temperatures. The external quantum efficiency (EQE) reached a maximum of 4.09% with the emissive layer annealed at 50 °C. The EQE dropped by ~35% (to 2.72%) for OLEDs with the emissive layers annealed at 200 °C. The observed performances of OLEDs were found to be closely related to thermal properties of polymer Super Yellow. The results reported here provide an important guideline for processing emissive layers and are significant for OLED and other organic electronics research communities.

  2. Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting

    SciTech Connect

    James Perkins; Matthew Stevenson; Gagan Mahan; Seth Coe-Sullivan; Peter Kazlas

    2011-01-21

    With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices.

  3. Effect of thermal annealing Super Yellow emissive layer on efficiency of OLEDs

    NASA Astrophysics Data System (ADS)

    Burns, Samantha; MacLeod, Jennifer; Trang Do, Thu; Sonar, Prashant; Yambem, Soniya D.

    2017-01-01

    Thermal annealing of the emissive layer of an organic light emitting diode (OLED) is a common practice for solution processable emissive layers and reported annealing temperatures varies across a wide range of temperatures. We have investigated the influence of thermal annealing of the emissive layer at different temperatures on the performance of OLEDs. Solution processed polymer Super Yellow emissive layers were annealed at different temperatures and their performances were compared against OLEDs with a non-annealed emissive layer. We found a significant difference in the efficiency of OLEDs with different annealing temperatures. The external quantum efficiency (EQE) reached a maximum of 4.09% with the emissive layer annealed at 50 °C. The EQE dropped by ~35% (to 2.72%) for OLEDs with the emissive layers annealed at 200 °C. The observed performances of OLEDs were found to be closely related to thermal properties of polymer Super Yellow. The results reported here provide an important guideline for processing emissive layers and are significant for OLED and other organic electronics research communities.

  4. Advances in OLED/OPD-based sensors and spectrometer-on-a-chip (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph; Kaudal, Rajiv; Manna, Eeshita; Fungura, Fadzai; Shinar, Ruth

    2016-09-01

    We describe ongoing advances toward achieving all-organic optical sensors and a spectrometer on a chip. Two-dimensional combinatorial arrays of microcavity OLEDs (μcOLEDs) with systematically varying optical cavity lengths are fabricated on a single chip by changing the thickness of different organic and/or spacer layers sandwiched between two metal electrodes (one very thin) that form the cavity. The broad spectral range is achieved by utilizing materials that result in white OLEDs (WOLEDs) when fabricated on a standard ITO substrate. The tunable and narrower emissions from the μcOLEDs serve as excitation sources in luminescent sensors and in monitoring light absorption. For each wavelength, the light from the μcOLED is partially absorbed by a sample under study and the light emitted by an electronically excited sample, or the transmitted light is detected by a photodetector (PD). To obtain a compact monitor, an organic PD (OPD) or a perovskite-based PD is integrated with the μcOLED array. We show the potential of encompassing a broader wavelength range by using WOLED materials to fabricate the μcOLEDs. The utility of the all-organic analytical devices is demonstrated by monitoring oxygen, and bioanalytes based on oxygen detection, as well as the absorption spectra of dyes.

  5. Effect of thermal annealing Super Yellow emissive layer on efficiency of OLEDs

    PubMed Central

    Burns, Samantha; MacLeod, Jennifer; Trang Do, Thu; Sonar, Prashant; Yambem, Soniya D.

    2017-01-01

    Thermal annealing of the emissive layer of an organic light emitting diode (OLED) is a common practice for solution processable emissive layers and reported annealing temperatures varies across a wide range of temperatures. We have investigated the influence of thermal annealing of the emissive layer at different temperatures on the performance of OLEDs. Solution processed polymer Super Yellow emissive layers were annealed at different temperatures and their performances were compared against OLEDs with a non-annealed emissive layer. We found a significant difference in the efficiency of OLEDs with different annealing temperatures. The external quantum efficiency (EQE) reached a maximum of 4.09% with the emissive layer annealed at 50 °C. The EQE dropped by ~35% (to 2.72%) for OLEDs with the emissive layers annealed at 200 °C. The observed performances of OLEDs were found to be closely related to thermal properties of polymer Super Yellow. The results reported here provide an important guideline for processing emissive layers and are significant for OLED and other organic electronics research communities. PMID:28106082

  6. Evidence that the Yeast Desaturase Ole1p Exists as a Dimer In Vivo

    SciTech Connect

    Lou, Y.; Shanklin, J.

    2010-06-18

    Desaturase enzymes are composed of two classes, the structurally well characterized soluble class found predominantly in the plastids of higher plants and the more widely distributed but poorly structurally defined integral membrane class. Despite their distinct evolutionary origins, the two classes both require an iron cofactor and molecular oxygen for activity and are inhibited by azide and cyanide, suggesting strong mechanistic similarities. The fact that the soluble desaturase is active as a homodimer prompted us test the hypothesis that an archetypal integral membrane desaturase from Saccharomyces cerevisiae, the {Delta}{sup o}-acyl-Co-A desaturase Ole1p, also exhibits a dimeric organization. Ole1p was chosen because it is one of the best characterized integral membrane desaturase and because it retains activity when fused with epitope tags. FLAG-Ole1p was detected by Western blotting of immunoprecipitates in which anti-Myc antibodies were used for capture from yeast extracts co-expressing Ole1p-Myc and Ole1p-FLAG. Interaction was confirmed by two independent bimolecular complementation assays (i.e. the split ubiquitin system and the split luciferase system). Co-expression of active and inactive Ole1p subunits resulted in an {approx}75% suppression of the accumulation of palmitoleic acid, demonstrating that the physiologically active form of Ole1p in vivo is the dimer in which both protomers must be functional.

  7. Recent progress in OLED and flexible displays and their potential for application to aerospace and military display systems

    NASA Astrophysics Data System (ADS)

    Sarma, Kalluri

    2015-05-01

    Organic light emitting diode (OLED) display technology has advanced significantly in recent years and it is increasingly being adapted in consumer electronics products with premium performance, such as high resolution smart phones, Tablet PCs and TVs. Even flexible OLED displays are beginning to be commercialized in consumer electronic devices such as smart phones and smart watches. In addition to the advances in OLED emitters, successful development and adoption of OLED displays for premium performance applications relies on the advances in several enabling technologies including TFT backplanes, pixel drive electronics, pixel patterning technologies, encapsulation technologies and system level engineering. In this paper we will discuss the impact of the recent advances in LTPS and AOS TFTs, R, G, B and White OLED with color filter pixel architectures, and encapsulation, on the success of the OLEDs in consumer electronic devices. We will then discuss potential of these advances in addressing the requirements of OLED and flexible displays for the military and avionics applications.

  8. Electroluminescence property of organic light emitting diode (OLED)

    SciTech Connect

    Özdemir, Orhan; Kavak, Pelin; Saatci, A. Evrim; Gökdemir, F. Pınar; Menda, U. Deneb; Can, Nursel; Kutlu, Kubilay; Tekin, Emine; Pravadalı, Selin

    2013-12-16

    Transport properties of electrons and holes were investigated not only in a anthracene-containing poly(p-phenylene-ethynylene)- alt - poly(p-phenylene-vinylene) (PPE-PPV) polymer (AnE-PVstat) light emitting diodes (OLED) but also in an ITO/Ag/polymer/Ag electron and ITO/PEDOT:PSS/polymer/Au hole only devices. Mobility of injected carriers followed the Poole-Frenkel type conduction mechanism and distinguished in the frequency range due to the difference of transit times in admittance measurement. Beginning of light output took place at the turn-on voltage (or flat band voltage), 1.8 V, which was the difference of energy band gap of polymer and two barrier offsets between metals and polymer.

  9. Water-soluble iridium phosphorescent complexes for OLED applications

    NASA Astrophysics Data System (ADS)

    Eum, Min-Sik; Yoon, Heekoo; Kim, Tae Hyung

    2012-09-01

    Newly prepared water-soluble iridium phosphorescent complexes, trans-[Ir(ppy)(PAr3)2(H)L]0,+ (ppy = bidentate 2-phenylpyridinato anionic ligand; L= Cl (1), CO (2), CN- (3); H being trans to the nitrogen of ppy ligand; PAr3 (TPPTS) = P(m-C6H4SO3Na)3), have been synthesized and characterized. Those complexes containing water-soluble phosphine ligands can emit any color region as altering cyclometalated ligands in aqueous media with high quantum efficiencies. Even though these water-soluble phosphorescent iridium complexes can be the sensing probe for toxic CO gas and CN anion, they will be capable of promising materials in the solution processible OLED applications.

  10. Effect of ITO surface modification on the OLED device lifetime.

    PubMed

    Yu, Szu-Yen; Chang, Jung-Hung; Wang, Po-Sheng; Wu, Chi-I; Tao, Yu-Tai

    2014-07-01

    Pretreatment of the indium tin oxide (ITO) surface is generally adopted to improve the charge injection and device performance in the fabrication of organic light-emitting diodes (OLEDs). For the common approaches of surface treatment, such as oxygen plasma treatment, self-assembled monolayer (SAM) adsorption, and the PEDOT:PSS coating, different effects on the device lifetime were observed. A distinctly different driving voltage change with device operation time was obtained and was correlated with the device lifetime. The fast increase in driving voltage for devices based on oxygen-plasma-treated ITO is attributed to the work function change as a result of the change in the composition of the interface with device operation, whereas a rather stable work function for SAM-modified ITO is suggested due to the permanent dipoles associated with the monolayer and the protecting effect of the covalently bound monolayer on the surface composition.

  11. On the role of polar molecules and the barrier for charge injection in OLEDs

    NASA Astrophysics Data System (ADS)

    Altazin, S.; Züfle, S.; Knapp, E.; Kirsch, C.; Schmidt, T. D.; Jäger, L.; Brütting, W.; Ruhstaller, B.

    2016-09-01

    Many electron transport layer materials (ETL) employed in state of the art organic light emitting diodes (OLEDs) are known to be polar. We combine for the first time simulations and electrical characterization of OLEDs based on polar ETL, in order to understand the impact of such materials on the device operation. Depending on the orientation of the dipole orientation, simulations predict either a benefit or a disadvantage of the polar ETL for the device performance. We also show that OLEDs featuring a polar material are perfectly suited for extracting mobility activation energy and Injection barrier from the anode to the ETL.

  12. Next Generation Hole Injection/Transport Nano-Composites for High Efficiency OLED Development

    SciTech Connect

    King Wang

    2009-07-31

    The objective of this program is to use a novel nano-composite material system for the OLED anode coating/hole transport layer. The novel anode coating is intended to significantly increase not only hole injection/transport efficiency, but the device energy efficiency as well. Another goal of the Core Technologies Program is the optimization and scale-up of air-stable and cross-linkable novel HTL nano-composite materials synthesis and the development of low-cost, large-scale mist deposition processes for polymer OLED fabrication. This proposed technology holds the promise to substantially improve OLED energy efficiency and lifetime.

  13. Development of functional nano-particle layer for highly efficient OLED

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Hyun; Kim, Min-Hoi; Choi, Haechul; Choi, Yoonseuk

    2015-12-01

    Organic light emitting diodes (OLEDs) are now widely commercialized in market due to many advantages such as possibility of making thin or flexible devices. Nevertheless there are still several things to obtain the high quality flexible OLEDs, one of the most important issues is the light extraction of the device. It is known that OLEDs have the typical light loss such as the waveguide loss, plasmon absorption loss and internal total reflection. In this paper, we demonstrate the one-step processed light scattering films with aluminum oxide nano-particles and polystyrene matrix composite to achieve highly efficient OLEDs. Optical characteristics and surface roughness of light scattering film was optimized by changing the mixing concentration of Al2O3 nano-particles and investigated with the atomic force microscopy and hazemeter, respectively.

  14. Random nanostructure scattering layer for suppression of microcavity effect and light extraction in OLEDs.

    PubMed

    Shin, Jin-Wook; Cho, Doo-Hee; Moon, Jaehyun; Joo, Chul Woong; Lee, Jonghee; Huh, Jin Woo; Park, Seung Koo; Han, Jun-Han; Cho, Nam Sung; Hwang, Joohyun; Chu, Hye Yong; Lee, Jeong-Ik

    2014-06-15

    In this study, we investigated the effect of a random nanostructure scattering layer (RSL) on the microcavity and light extraction in organic light emitting diodes (OLEDs). In the case of the conventional OLED, the optical properties change with the thickness of the hole transporting layer (HTL) because of the presence of a microcavity. However, OLEDs equipped with the an RSL showed similar values of external quantum efficiency and luminous efficacy regardless of the HTL thickness. These phenomena can be understood by the scattering effect because of the RSL, which suppresses the microcavity effect and extracts the light confined in the device. Moreover, OLEDs with the RSL led to reduced spectrum and color changes with the viewing angle.

  15. Soft lithography microlens fabrication and array for enhanced light extraction from organic light emitting diodes (OLEDs)

    DOEpatents

    Leung, Wai Y.; Park, Joong-Mok; Gan, Zhengqing; Constant, Kristen P.; Shinar, Joseph; Shinar, Ruth; ho, Kai-Ming

    2014-06-03

    Provided are microlens arrays for use on the substrate of OLEDs to extract more light that is trapped in waveguided modes inside the devices and methods of manufacturing same. Light extraction with microlens arrays is not limited to the light emitting area, but is also efficient in extracting light from the whole microlens patterned area where waveguiding occurs. Large microlens array, compared to the size of the light emitting area, extract more light and result in over 100% enhancement. Such a microlens array is not limited to (O)LEDs of specific emission, configuration, pixel size, or pixel shape. It is suitable for all colors, including white, for microcavity OLEDs, and OLEDs fabricated directly on the (modified) microlens array.

  16. Color tunability in multilayer OLED based on DCM doped in a PVK matrix

    NASA Astrophysics Data System (ADS)

    Petrova, P. K.; Ivanov, P. I.; Tomova, R. L.

    2014-12-01

    In this work, we present our achievements in color tunability in novel multilayer organic light-emitting diodes (OLEDs) based on DCM (4-(Dicyanomethylene)-2-methyl-6-[p- (dimethylamino)styryl]-4H-pyran) as red emitter doped in a composite PVK:TPD holetransporting layer, DPVBi (4,4'-Bis(2,2-diphenylvinyl)-1,1'-biphenyl) as a separate blue emitting layer, BAlq (aluminum bis(2-methyl-8-quinolinate)-4-phenylphenolate) as holeblocking layer and blue emitter at the same time, and Zn(BTz)2 (zinc bis(2-(2-hydroxyphenyl) benzothiazole)) as yellow emitter and electron transporting layer. By modification of the OLED structure and changing the DCM doped concentration in the matrix (in the range of 0 up to 5 %) the color tunability of OLED structures has been obtained. The efficiencies, luminance and chromaticity coordinates of the fabricated OLED structures have been specified.

  17. OLED luminaires: Device arrays with 99.6 % geometric fill factor structured by femtosecond laser ablation.

    PubMed

    Fragoso García, Joshua; Höfle, Stefan; Zhang, Min; Dlugosch, Julian; Friedrich, Torsten; Wagner, Susanne; Colsmann, Alexander

    2017-09-25

    The plethora of design opportunities renders organic light emitting diodes (OLEDs) ideal luminaires for general lighting applications. Progressing from lab-scale device concepts to large-area applications calls for smart device designs that are scalable and, at the same time, unsusceptible to resistive losses within the electrodes. By employing direct pulsed femtosecond laser structuring, we fabricate OLED luminaires comprising monolithically interconnected OLED arrays. We determine the laser ablation thresholds and the optimized process parameters for all functional layers. The clean laser cuts with precise ablation depths show about no damage to adjacent layers or any ridges, hence avoiding unwanted short-cuts or device isolation. All processes are scalable. The threefold structuring of the OLED luminaire is confined within 45 µm, yielding a geometric fill factor beyond 99 % and hence a very homogenous device perception.

  18. A wuantitative structure-property relationship study of the glass transition temperature of OLED materials.

    PubMed

    Yin, ShiWei; Shuai, Z; Wang, Yilin

    2003-01-01

    Organic light-emitting-diodes (OLED) materials possess great potential applications. Stability and efficiency are the two major factors to be improved toward commercialization, especially the thermal stability, because in the working device, the organic molecular materials can have high temperature. One of the most important factors, which influences the stability, is the glass transition temperature (T(g)). We employed a QSPR (quantitative structure-properties relationship) approach to establish a theoretical model to predict the glass transition temperatures of organic molecular materials. A six-parameter correlation with the squared correlation coefficient R(2) = 0.9270 and the average absolute error 8.5 K was developed for a diverse set of 73 OLED materials. All descriptors were derived solely from the chemical structures of the organic compounds. A satisfactory average absolute error of 17.9 K for a test set of 15 OLED materials makes the model very useful for the prediction of the unknown OLED materials.

  19. Materials design concepts for efficient blue OLEDs: A joint theoretical and experimental study

    SciTech Connect

    Polikarpov, Evgueni; Padmaperuma, Asanga B.

    2012-04-01

    Since their discovery, organic light emitting devices have evolved from a scientific curiosity into a technology with applications in flat panel displays and the potential to revolutionize the lighting market. During their relatively short history, the technology incorporated into OLEDs has rapidly advanced. Device quantum efficiencies have increased more than 20-fold since the first OLEDs, approaching the theoretical limit for internal quantum efficiencies. , , At this point, OLED research moves towards optimization of manufacturing processes, drive circuitry, light extraction, and overall cost reduction. However, finding the organic materials that provide both operational stability and high efficiency for the devices still remains one of the biggest challenges, particularly for blue emission. In this presentation, we will describe our approach to design functional OLED materials to meet the complex criteria set forth by device efficiency and stability goals.

  20. Dual side transparent OLED 3D display using Gabor super-lens

    NASA Astrophysics Data System (ADS)

    Chestak, Sergey; Kim, Dae-Sik; Cho, Sung-Woo

    2015-03-01

    We devised dual side transparent 3D display using transparent OLED panel and two lenticular arrays. The OLED panel is sandwiched between two parallel confocal lenticular arrays, forming Gabor super-lens. The display provides dual side stereoscopic 3D imaging and floating image of the object, placed behind it. The floating image can be superimposed with the displayed 3D image. The displayed autostereoscopic 3D images are composed of 4 views, each with resolution 64x90 pix.

  1. GATEWAY Report Brief: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    SciTech Connect

    None, None

    2016-05-31

    Summary of a GATEWAY report evaluation at the offices of Aurora Lighting Design, Inc., in Grayslake, IL, where the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  2. Color in the corners: ITO-free white OLEDs with angular color stability.

    PubMed

    Gaynor, Whitney; Hofmann, Simone; Christoforo, M Greyson; Sachse, Christoph; Mehra, Saahil; Salleo, Alberto; McGehee, Michael D; Gather, Malte C; Lüssem, Björn; Müller-Meskamp, Lars; Peumans, Peter; Leo, Karl

    2013-08-07

    High-efficiency white OLEDs fabricated on silver nanowire-based composite transparent electrodes show almost perfectly Lambertian emission and superior angular color stability, imparted by electrode light scattering. The OLED efficiencies are comparable to those fabricated using indium tin oxide. The transparent electrodes are fully solution-processable, thin-film compatible, and have a figure of merit suitable for large-area devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. AcOLeDMAP and BnOLeDMAP: Conformationally Restricted Nucleophilic Catalysts for Enantioselective Rearrangement of Indolyl Acetates and Carbonates

    PubMed Central

    Duffey, Trisha A.; Shaw, Scott A.; Vedejs, Edwin

    2009-01-01

    The rate of indolyl O- to C-acetyl or carboxyl rearrangement is accelerated by the electron withdrawing N-diphenylacetyl group (DPA) using the conformationally restricted chiral catalysts AcOLeDMAP (12b) and BnOLeDMAP (13b). Highly enantioselective conversion to quaternary C-acetylated and C-carboxylated oxindoles is observed, even for substrates containing branched substituents. The rearrangement of the carboxylate substrates 19 occurs with complementary enantiofacial selectivity using catalyst 13b compared to the acetyl migrations of 16 catalyzed by 12b. Access to N-unsubstituted oxindoles is demonstrated by DPA cleavage with Et2NH. PMID:19093886

  4. Phosphorescent OLEDs: Sky-Blue Phosphorescent OLEDs with 34.1% External Quantum Efficiency Using a Low Refractive Index Electron Transporting Layer (Adv. Mater. 24/2016).

    PubMed

    Shin, Hyun; Lee, Jeong-Hwan; Moon, Chang-Ki; Huh, Jin-Suk; Sim, Bomi; Kim, Jang-Joo

    2016-06-01

    J.-J. Kim and co-workers achieve highly efficient blue organic light-emitting diodes (OLEDs) using a low-refractive-index layer. As described on page 4920, an external quantum efficiency over 34% is achieved, owing to the low refractive index of the materials. A milepost and a shining entrance of the castle are the metaphor indicating the way to highly efficient blue OLEDs. On the way to the castle, the depicted chemical structures serve as the light-emitting layer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Flexible low-power-consumption OLED displays for a universal communication device

    NASA Astrophysics Data System (ADS)

    Hack, Michael G.; Chwang, Anna B.; Lu, Min-Hao M.; Kwong, Raymond C.; Weaver, Michael S.; Tung, Yeh-Jiun; Brown, Julie J.

    2003-09-01

    In this paper we will outline the technical challenges and progress towards enabling a novel communication device based on a roll-out, low power consumption, OLED display. Advanced mobile communication devices require a bright, high information content display in a small, light-weight, low power consumption package. We believe that phosphorescent OLED (PHOLED) technology fabricated on a truly flexible substrate, enables a mobile Universal Communication Device (UCD) to offer a high information content display in an extendable form, while rolling up into a small form factor when not in use. This communication device is of great interest for a range of both consumer and military applications. From the display perspective, the key component is achieving a long-lived, low power consumption display. We believe the OLEDs are the preferred display media, and in this talk we will outline our flexible phosphorescent OLED technology. The key to reliable operation is to ensure that the organic materials are fully encapsulated in a package designed for repetitive flexing. UDC has been developing long-lived flexible OLED (FOLED) displays based on plastic substrates and multi-layer monolithic encapsulation. Recent progress in this area will also be reported. Finally, we will outline the backplane requirements for flexible OLED displays and compare the various technology options that can be used to fabricate the UCD.

  6. The electrodeposition of multilayers on a polymeric substrate in Flexible Organic Light Emitting Diode (OLED)

    NASA Astrophysics Data System (ADS)

    Guedes, Andre F. S.; Guedes, Vilmar P.; Tartari, Simone; Cunha, Idaulo Jose

    2016-09-01

    The development of Organic Light Emitting Diode (OLED), using an optically transparent substrate material and organic semiconductor materials, has been widely utilized by the electronic industry when producing new technological products. The OLED are the base Poly(3,4-ethylenedioxythiophene), PEDOT, Poly(p-phenylenevinylene), PPV, and Polyaniline, PANI, were deposited in Indium Tin Oxide, ITO, and characterized by UV-Visible Spectroscopy (UV-Vis), Optical Parameters (OP) and Scanning Electron Microscopy (SEM). In addition, the thin film obtained by the deposition of PANI, prepared in perchloric acid solution, was identified through PANI-X1. The result obtained by UV-Vis has demonstrated that the PET/ITO/PEDOT/PPV/PANI-X1/Al layer does not have displacement of absorption for wavelengths greaters after spin-coating and electrodeposition. Thus, the spectral irradiance of the OLED informed the irradiance of 100 W/m2, and this result, compared with the standard Light Emitting Diode (LED), has indicated that the OLED has higher irradiance. After 1200 hours of electrical OLED tests, the appearance of nanoparticles visible for images by SEM, to the migration process of organic semiconductor materials, was present, then. Still, similar to the phenomenon of electromigration observed in connections and interconnections of microelectronic devices, the results have revealed a new mechanism of migration, which raises the passage of electric current in OLED.

  7. Novel Smart Windows Based on Transparent Phosphorescent OLEDs

    SciTech Connect

    Brian D'Andrade; Stephen Forest

    2006-09-15

    In this program, Universal Display Corporation (UDC) and Princeton University developed the use of white transparent phosphorescent organic light emitting devices (PHOLEDs{trademark}) to make low-cost ''transparent OLED (TOLED) smart windows'', that switch rapidly from being a highly efficient solid-state light source to being a transparent window. PHOLEDs are ideal for large area devices, and the UDC-Princeton team has demonstrated white PHOLEDs with efficiencies of >24 lm/W at a luminance of 1,000 cd/m{sup 2}. TOLEDs have transparencies >70% over the visible wavelengths of light, but their transparency drops to less than 5% for wavelengths shorter than 350 nm, so they can also be used as ultraviolet (UV) light filters. In addition to controlling the flow of UV radiation, TOLEDs coupled with an electromechanical or electrically activated reflecting shutter on a glass window can be employed to control the flow of heat from infrared (IR) radiation by varying the reflectance/transparency of the glass for wavelengths greater than 800nm. One particularly attractive shutter technology is reversible electrochromic mirrors (REM). Our goal was therefore to integrate two innovative concepts to meet the U.S. Department of Energy goals: high power efficiency TOLEDs, plus electrically controlled reflectors to produce a ''smart window''. Our efforts during this one year program have succeeded in producing a prototype smart window shown in the Fig. I, below. The four states of the smart window are pictured: reflective with lamp on, reflective with lamp off, transparent with lamp on, and transparent with lamp off. In the transparent states, the image is an outdoor setting viewed through the window. In the reflective states, the image is an indoor setting viewed via reflection off the window. We believe that the integration of our high efficiency white phosphorescent TOLED illumination source, with electrically activated shutters represents an innovative low-cost approach to

  8. Surface treatment on polyethylenimine interlayer to improve inverted OLED performance

    NASA Astrophysics Data System (ADS)

    Wei, Chang-Ting; Zhuang, Jin-Yong; Chen, Ya-Li; Zhang, Dong-Yu; Su, Wen-Ming; Cui, Zheng

    2016-10-01

    Polyethylenimine (PEI) interlayer rinsing with different solvents for inverted organic light emitting diodes (OLEDs) is systematically studied in this paper. In comparison with the pristine one, the maximum current efficiency (CE max) and power efficiency (PE max) are enhanced by 21% and 22% for the device rinsing by ethylene glycol monomethyl ether (EEA). Little effect is found on the work function of the PEI interlayer rinsed by deionized water (DI), ethanol (EtOH), and EEA. On the other hand, the surface morphologies of PEI through different solvent treatments are quite different. Our results indicates that the surface morphology is the key to improving the device performance for IOLED as the work function of PEI keeps stable. Project supported by the National Key Basic Research Project of China (Grant No. 2015CB351901), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA09020201), the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2013206), the National Natural Science Foundation of China (Grant No. 21402233), and the Natural Science Foundation of Jiangsu Province, China (Grant Nos. BK2012631 and BK20140387).

  9. New concept for in-line OLED manufacturing

    NASA Astrophysics Data System (ADS)

    Hoffmann, U.; Landgraf, H.; Campo, M.; Keller, S.; Koening, M.

    2011-03-01

    A new concept of a vertical In-Line deposition machine for large area white OLED production has been developed. The concept targets manufacturing on large substrates (>= Gen 4, 750 x 920 mm2) using linear deposition source achieving a total material utilization of >= 50 % and tact time down to 80 seconds. The continuously improved linear evaporation sources for the organic material achieve thickness uniformity on Gen 4 substrate of better than +/- 3 % and stable deposition rates down to less than 0.1 nm m/min and up to more than 100 nm m/min. For Lithium-Fluoride but also for other high evaporation temperature materials like Magnesium or Silver a linear source with uniformity better than +/- 3 % has been developed. For Aluminum we integrated a vertical oriented point source using wire feed to achieve high (> 150 nm m/min) and stable deposition rates. The machine concept includes a new vertical vacuum handling and alignment system for Gen 4 shadow masks. A complete alignment cycle for the mask can be done in less than one minute achieving alignment accuracy in the range of several 10 μm.

  10. White OLED in Hybrid Structure for Enhancing Color Purity.

    PubMed

    Kim, Dong-Eun; Kang, Min-Jae; Park, Gwang-Ryeol; Lee, Burm-Jong; Kwon, Young-Soo; Shin, Hoon-Kyu

    2016-06-01

    We synthesized the red emission material, bis(1,4-bis(5-phenyloxazol-2-yl)phenyl) iridium(picolate) [Ir-complexes] and the blue emission material, bis (2-(2-hydroxyphenyl) benzoxazolate)zinc [Zn(HPB)2]. White Organic Light Emitting Diodes were fabricated by using Zn(HPB)2 for a blue emitting layer, Ir-complexes for a red emitting layer and a tris (8-hydroxy quinoline)aluminum [Alq3] for a green emitting layer. The important experimental results obtained, white OLED was fabricated by using double emitting layers of Zn(HPB)2 and Alq3:Ir-complexes, and hole blocking layer of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline[BCP]. We also varied the thickness of BCP. When the thickness of BCP layer was 5 nm, white emission was achieved. We obtained a maximum luminance of 5400 cd/m2 at a current density of 650 mA/cm2. The CIE coordinates was (0.339, 0.323) at voltage of 10 V.

  11. AMOLED (active matrix OLED) functionality and usable lifetime at temperature

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Prache, Olivier; Jones, Susan

    2005-05-01

    Active Matrix Organic Light Emitting Diode (AMOLED) displays are known to exhibit high levels of performance, and these levels of performance have continually been improved over time with new materials and electronics design. eMagin Corporation developed a manually adjustable temperature compensation circuit with brightness control to allow for excellent performance over a wide temperature range. Night Vision and Electronic Sensors Directorate (US Army) tested the performance and survivability of a number of AMOLED displays in a temperature chamber over a range from -55°C to +85°C. Although device performance of AMOLEDs has always been its strong suit, the issue of usable display lifetimes for military applications continues to be an area of discussion and research. eMagin has made improvements in OLED materials and worked towards the development of a better understanding of usable lifetime for operation in a military system. NVESD ran luminance degradation tests of AMOLED panels at 50°C and at ambient to characterize the lifetime of AMOLED devices. The result is a better understanding of the applicability of AMOLEDs in military systems: where good fits are made, and where further development is needed.

  12. Active matrix OLED for rugged HMD and viewfinder applications

    NASA Astrophysics Data System (ADS)

    Low, Kia; Jones, Susan K.; Prache, Olivier; Fellowes, David A.

    2004-09-01

    We present characterization of a full-color 852x3x600-pixel, active matrix organic light emitting diode (AMOLED) color microdisplay (eMagin Corporation's SVGA+ display) for environmentally demanding applications. The results show that the AMOLED microdisplay can provide cold-start turn-on and operate at extreme temperature conditions, far in excess of non-emissive displays. Correction factors for gamma response of the AMOLED microdisplay as a function of temperature have been determined to permit consistent luminance and contrast from -40°C to over +80°C. Gamma adjustments are made by a simple temperature compensation adjustment of the reference voltages of the AMOLED. The typical room temperature full-on luminance half-life of the SVGA+ full color display organic light emitting diode (OLED) display at over 3,000 hr at a starting luminance at approx. 100 cd/m2, translates to more than 15,000 hr of continuous full-motion video usage, based on a 25% duty cycle at a typical 50-60 cd/m2 commercial luminance level, or over 60,000 hr half-life in monochrome white usage, or over 100,000 hr luminance half-life in monochrome yellow usage at similar operating conditions. Half life at typical night vision luminance levels would be much longer.

  13. Hole-Rich Host Materials for Blue Phosphorescent OLEDs

    SciTech Connect

    Cosimbescu, Lelia; Polikarpov, Evgueni; Swensen, James S.; Darsell, Jens T.; Padmaperuma, Asanga B.

    2011-04-01

    Stable and efficient organic light emitting devices (OLEDs) are an integral part of the future of lighting and displays. The hole accumulation at the hole transport/emissive layer interface in such devices is considered to be a major pathway for degradation and efficiency loss. Here we report the design and synthesis of two charge-transporting host materials, based on the phosphine oxide (PO) moiety, engineered to improve hole transport of the emissive layer. The compounds are an extension of a molecular design strategy already explored and reported by our team which incorporates a hole transporting moiety and an electron transporting moiety. These novel materials were designed with two hole transport moieties (HTms) to further improve hole transport, compared to the first generation host materials that were designed with one hole transport functional group. The triplet exciton energy was maintained at a level greater than that of FIrpic (2.7 eV) to prevent exciton quenching. The EHOMO and ELUMO of the two classes of molecules (i.e., one HTm vs. 2 HTms) were similar, however their device performance varied greatly. Emission zone experiments were conducted to further understand the differences between molecules.

  14. Widespread Head-to-Head Hydrocarbon Biosynthesis in Bacteria and Role of OleA ▿ †

    PubMed Central

    Sukovich, David J.; Seffernick, Jennifer L.; Richman, Jack E.; Gralnick, Jeffrey A.; Wackett, Lawrence P.

    2010-01-01

    Previous studies identified the oleABCD genes involved in head-to-head olefinic hydrocarbon biosynthesis. The present study more fully defined the OleABCD protein families within the thiolase, α/β-hydrolase, AMP-dependent ligase/synthase, and short-chain dehydrogenase superfamilies, respectively. Only 0.1 to 1% of each superfamily represents likely Ole proteins. Sequence analysis based on structural alignments and gene context was used to identify highly likely ole genes. Selected microorganisms from the phyla Verucomicrobia, Planctomyces, Chloroflexi, Proteobacteria, and Actinobacteria were tested experimentally and shown to produce long-chain olefinic hydrocarbons. However, different species from the same genera sometimes lack the ole genes and fail to produce olefinic hydrocarbons. Overall, only 1.9% of 3,558 genomes analyzed showed clear evidence for containing ole genes. The type of olefins produced by different bacteria differed greatly with respect to the number of carbon-carbon double bonds. The greatest number of organisms surveyed biosynthesized a single long-chain olefin, 3,6,9,12,15,19,22,25,28-hentriacontanonaene, that contains nine double bonds. Xanthomonas campestris produced the greatest number of distinct olefin products, 15 compounds ranging in length from C28 to C31 and containing one to three double bonds. The type of long-chain product formed was shown to be dependent on the oleA gene in experiments with Shewanella oneidensis MR-1 ole gene deletion mutants containing native or heterologous oleA genes expressed in trans. A strain deleted in oleABCD and containing oleA in trans produced only ketones. Based on these observations, it was proposed that OleA catalyzes a nondecarboxylative thiolytic condensation of fatty acyl chains to generate a β-ketoacyl intermediate that can decarboxylate spontaneously to generate ketones. PMID:20418421

  15. Blue phosphorescent OLEDs with 34.1% external quantum efficiency using a low refractive index electron transporting material

    NASA Astrophysics Data System (ADS)

    Shin, Hyun; Lee, Jeong-Hwan; Moon, Chang-Ki; Huh, Jin-Suk; Sim, Bomi; Kim, Jang-Joo

    2016-09-01

    In this study, we demonstrate a blue OLED with the EQE of 34% and power efficiency of 79.6 lm W-1 using low refractive index electron transporting layer which are the highest efficiencies ever reported in blue OLEDs. In addition, we quantitatively calculated maximum achievable outcoupling efficiencies according to change of refractive indices, which can be used to estimate the achievable outcoupling efficiency of OLEDs without fabrication. The simulation indicates that EQE over 60% can be achievable in PhOLEDs if refractive indices of consisting organic materials' are close to 1.5.

  16. Computational study of bindings of olive leaf extract (OLE) to HIV-1 fusion protein gp41.

    PubMed

    Bao, J; Zhang, D W; Zhang, J Z H; Huang, P Lee; Huang, P Lin; Lee-Huang, S

    2007-06-12

    Recent experimental study found that OLE (olive leaf extract) has anti-HIV activity by blocking the HIV virus entry to host cells [Lee-Huang, S., Zhang, L., Huang, P.L., Chang, Y. and Huang, P.L. (2003) Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment. Biochem. Biophys. Res. Commun. 307, 1029; Lee-Huang, S., Huang, P.L., Zhang, D., Lee, J.W., Bao, J., Sun, Y., Chang, Y.-Tae, Zhang, J.Z.H. and Huang, P.L. (2007) Discovery of small-molecule HIV-1 fusion and integrase inhibitors oleuropein and hydroxytyrosol. Biochem. Biophys. Res. Commun. 354, 872-878, 879-884]. As part of a joint experimental and theoretical effort, we report here computational study to help identify and characterize the binding complexes of several main compounds of OLE (olive leaf extract) to HIV-1 envelop protein gp41. A number of possible binding modes are found by docking oleuropein and its metabolites, aglycone, elenolic acid and hydroxytyrosol, onto the hydrophobic pocket on gp41. Detailed OLE-gp41 binding interactions and free energies of binding are obtained through molecular dynamics simulation and MM-PBSA calculation. Specific molecular interactions in our predicted OLE/gp41 complexes are identified and hydroxytyrosol is identified to be the main moiety for binding to gp41. This computational study complements the corresponding experimental investigation and helps establish a good starting point for further refinement of OLE-based gp41 inhibitors.

  17. Catalytic Determinants of Alkene Production by the Cytochrome P450 Peroxygenase OleTJE*

    PubMed Central

    Matthews, Sarah; Belcher, James D.; Tee, Kang Lan; Girvan, Hazel M.; McLean, Kirsty J.; Rigby, Stephen E. J.; Levy, Colin W.; Leys, David; Parker, David A.; Blankley, Richard T.; Munro, Andrew W.

    2017-01-01

    The Jeotgalicoccus sp. peroxygenase cytochrome P450 OleTJE (CYP152L1) is a hydrogen peroxide-driven oxidase that catalyzes oxidative decarboxylation of fatty acids, producing terminal alkenes with applications as fine chemicals and biofuels. Understanding mechanisms that favor decarboxylation over fatty acid hydroxylation in OleTJE could enable protein engineering to improve catalysis or to introduce decarboxylation activity into P450s with different substrate preferences. In this manuscript, we have focused on OleTJE active site residues Phe79, His85, and Arg245 to interrogate their roles in substrate binding and catalytic activity. His85 is a potential proton donor to reactive iron-oxo species during substrate decarboxylation. The H85Q mutant substitutes a glutamine found in several peroxygenases that favor fatty acid hydroxylation. H85Q OleTJE still favors alkene production, suggesting alternative protonation mechanisms. However, the mutant undergoes only minor substrate binding-induced heme iron spin state shift toward high spin by comparison with WT OleTJE, indicating the key role of His85 in this process. Phe79 interacts with His85, and Phe79 mutants showed diminished affinity for shorter chain (C10–C16) fatty acids and weak substrate-induced high spin conversion. F79A OleTJE is least affected in substrate oxidation, whereas the F79W/Y mutants exhibit lower stability and cysteine thiolate protonation on reduction. Finally, Arg245 is crucial for binding the substrate carboxylate, and R245E/L mutations severely compromise activity and heme content, although alkene products are formed from some substrates, including stearic acid (C18:0). The results identify crucial roles for the active site amino acid trio in determining OleTJE catalytic efficiency in alkene production and in regulating protein stability, heme iron coordination, and spin state. PMID:28053093

  18. Integrated OLED as excitation light source in fluorescent lateral flow immunoassays.

    PubMed

    Venkatraman, Vishak; Steckl, Andrew J

    2015-12-15

    The integration of organic light emitting diodes (OLEDs) as excitation light sources for quantum dot-based fluorescent lateral flow immunoassay systems (LFIA) was investigated. This approach has the potential to deliver a sensitive visible detection scheme for low-cost, disposable lab-on-chip point-of-care (POC) diagnosis system. Thin film phosphorescent green OLEDs fabricated on plastic substrates were integrated on-chip to excite the test line of a quantum dot-based LFIA (QD-LFIA). OLEDs were fabricated by sequential deposition of organic thin films (total of ~100 nm) onto ITO-coated PET substrates. CdSe/ZnS QDs emitting at 655 nm and Au nanoparticles (NP - 10 nm size) conjugated antibodies were used for the fluorescence QD-LFIA and conventional reflection-mode Au NP-LFIA, respectively. Thin plastic color light filters were integrated for filtering the excitation light source and, thereby, increasing the contrast of the emitted light for optimized visual detection. Integration of the OLED and color filters with the analytical membrane was achieved using adhesive techniques facilitated by the planar nature of the layers, which suggests possible large scale manufacturing using roll-to-roll processing. Gray scale analysis from digital images captured with a digital camera was used to quantify the visual sensitivity. The signal intensity, signal-to-noise ratio (SNR) and the limit of detection (LOD) of OLED integrated QD-LFIAs were compared to Au NP LFIAs. OLED QD-LFIA exhibited superior performance in all signal aspects: 7-8× higher signal intensity and SNR, and a 7× lower LOD of 3 nM (measured at S/N=3). These results demonstrate the potential of OLED-integrated in LFIA devices for obtaining sensitive, fast and low-cost POC diagnostics. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Catalytic Determinants of Alkene Production by the Cytochrome P450 Peroxygenase OleTJE.

    PubMed

    Matthews, Sarah; Belcher, James D; Tee, Kang Lan; Girvan, Hazel M; McLean, Kirsty J; Rigby, Stephen E J; Levy, Colin W; Leys, David; Parker, David A; Blankley, Richard T; Munro, Andrew W

    2017-03-24

    The Jeotgalicoccus sp. peroxygenase cytochrome P450 OleTJE (CYP152L1) is a hydrogen peroxide-driven oxidase that catalyzes oxidative decarboxylation of fatty acids, producing terminal alkenes with applications as fine chemicals and biofuels. Understanding mechanisms that favor decarboxylation over fatty acid hydroxylation in OleTJE could enable protein engineering to improve catalysis or to introduce decarboxylation activity into P450s with different substrate preferences. In this manuscript, we have focused on OleTJE active site residues Phe(79), His(85), and Arg(245) to interrogate their roles in substrate binding and catalytic activity. His(85) is a potential proton donor to reactive iron-oxo species during substrate decarboxylation. The H85Q mutant substitutes a glutamine found in several peroxygenases that favor fatty acid hydroxylation. H85Q OleTJE still favors alkene production, suggesting alternative protonation mechanisms. However, the mutant undergoes only minor substrate binding-induced heme iron spin state shift toward high spin by comparison with WT OleTJE, indicating the key role of His(85) in this process. Phe(79) interacts with His(85), and Phe(79) mutants showed diminished affinity for shorter chain (C10-C16) fatty acids and weak substrate-induced high spin conversion. F79A OleTJE is least affected in substrate oxidation, whereas the F79W/Y mutants exhibit lower stability and cysteine thiolate protonation on reduction. Finally, Arg(245) is crucial for binding the substrate carboxylate, and R245E/L mutations severely compromise activity and heme content, although alkene products are formed from some substrates, including stearic acid (C18:0). The results identify crucial roles for the active site amino acid trio in determining OleTJE catalytic efficiency in alkene production and in regulating protein stability, heme iron coordination, and spin state.

  20. Creation of a U.S. Phosphorescent OLED Lighting Panel Manufacturing Facility

    SciTech Connect

    Hack, Michael

    2013-09-30

    Universal Display Corporation (UDC) has pioneered high efficacy phosphorescent OLED (PHOLED™) technology to enable the realization of an exciting new form of high quality, energy saving solid-date lighting. In laboratory test devices, we have demonstrated greater than 100 lm/W conversion efficacy. In this program, Universal Display will demonstrate the scalability of its proprietary UniversalPHOLED technology and materials for the manufacture of white OLED lighting panels that meet commercial lighting targets. Moser Baer Technologies will design and build a U.S.- based pilot facility. The objective of this project is to establish a pilot phosphorescent OLED (PHOLED) manufacturing line in the U.S. Our goal is that at the end of the project, prototype lighting panels could be provided to U.S. luminaire manufacturers for incorporation into products to facilitate the testing of design concepts and to gauge customer acceptance, so as to facilitate the growth of the embryonic U.S. OLED lighting industry. In addition, the team will provide a cost of ownership analysis to quantify production costs including OLED performance metrics which relate to OLED cost such as yield, materials usage, cycle time, substrate area, and capital depreciation. This project was part of a new DOE initiative designed to help establish and maintain U.S. leadership in this program will support key DOE objectives by showing a path to meet Department of Energy Solid-State Lighting Manufacturing Roadmap cost targets, as well as meeting its efficiency targets by demonstrating the energy saving potential of our technology through the realization of greater than 76 lm/W OLED lighting panels by 2012.

  1. Olive cultivar origin is a major cause of polymorphism for Ole e 1 pollen allergen

    PubMed Central

    Hamman-Khalifa, AbdelMounim; Castro, Antonio Jesús; Jiménez-López, José Carlos; Rodríguez-García, María Isabel; Alché, Juan de Dios

    2008-01-01

    Background Pollens from different olive (Olea europaea L.) cultivars have been shown to differ significantly in their content in Ole e 1 and in their overall allergenicity. This allergen is, in addition, characterized by a high degree of polymorphism in its sequence. The purpose of this study is to evaluate the putative presence of divergences in Ole e 1 sequences from different olive cultivars. Results RNA from pollen individually collected from 10 olive cultivars was used to amplify Ole e 1 sequences by RT-PCR, and the sequences were analyzed by using different bioinformatics tools. Numerous nucleotide substitutions were detected throughout the sequences, many of which resulted in amino acid substitutions in the deduced protein sequences. In most cases variability within a single variety was much lower than among varieties. Key amino acid changes in comparison with "canonical" sequences previously described in the literature included: a) the substitution of C19-relevant to the disulphide bond structure of the protein-, b) the presence of an additional N-glycosylation motif, and c) point substitutions affecting regions of Ole e 1 already described like relevant for the immunogenicity/allergenicity of the protein. Conclusion Varietal origin of olive pollen is a major factor determining the diversity of Ole e 1 variants. We consider this information of capital importance for the optimal design of efficient and safe allergen formulations, and useful for the genetic engineering of modified forms of the allergen among other applications. PMID:18218146

  2. FDTD analysis of the light extraction efficiency of OLEDs with a random scattering layer.

    PubMed

    Kim, Jun-Whee; Jang, Ji-Hyang; Oh, Min-Cheol; Shin, Jin-Wook; Cho, Doo-Hee; Moon, Jae-Hyun; Lee, Jeong-Ik

    2014-01-13

    The light extraction efficiency of OLEDs with a nano-sized random scattering layer (RSL-OLEDs) was analyzed using the Finite Difference Time Domain (FDTD) method. In contrast to periodic diffraction patterns, the presence of an RSL suppresses the spectral shift with respect to the viewing angle. For FDTD simulation of RSL-OLEDs, a planar light source with a certain spatial and temporal coherence was incorporated, and the light extraction efficiency with respect to the fill factor of the RSL and the absorption coefficient of the material was investigated. The design results were compared to the experimental results of the RSL-OLEDs in order to confirm the usefulness of FDTD in predicting experimental results. According to our FDTD simulations, the light confined within the ITO-organic waveguide was quickly absorbed, and the absorption coefficients of ITO and RSL materials should be reduced in order to obtain significant improvement in the external quantum efficiency (EQE). When the extinction coefficient of ITO was 0.01, the EQE in the RSL-OLED was simulated to be enhanced by a factor of 1.8.

  3. Efficient, inkjet-printed TADF-OLEDs with an ultra-soluble NHetPHOS complex

    NASA Astrophysics Data System (ADS)

    Verma, Anand; Zink, Daniel M.; Fléchon, Charlotte; Leganés Carballo, Jaime; Flügge, Harald; Navarro, José M.; Baumann, Thomas; Volz, Daniel

    2016-03-01

    Using printed organic light-emitting diodes (OLEDs) for lighting, smart-packaging and other mass-market applications has remained a dream since the first working OLED devices were demonstrated in the late 1980s. The realization of this long-term goal is hindered by the very low abundance of iridium and problems when using low-cost wet chemical production processes. Abundant, solution-processable Cu(I) complexes promise to lower the cost of OLEDs. A new copper iodide NHetPHOS emitter was prepared and characterized in solid state with photoluminescence spectroscopy and UV photoelectron spectroscopy under ambient conditions. The photoluminescence quantum efficiency was determined as 92 ± 5 % in a thin film with yellowish-green emission centered around 550 nm. This puts the material on par with the most efficient copper complexes known so far. The new compound showed superior solubility in non-polar solvents, which allowed for the fabrication of an inkjet-printed OLED device from a decalin-based ink formulation. The emission layer could be processed under ambient conditions and was annealed under air. In a very simple stack architecture, efficiency values up to 45 cd A-1 corresponding to 13.9 ± 1.9 % EQE were achieved. These promising results open the door to printed, large-scale OLED devices with abundant copper emitters.

  4. A spectral measurement method for determining white OLED average junction temperatures

    NASA Astrophysics Data System (ADS)

    Zhu, Yiting; Narendran, Nadarajah

    2016-09-01

    The objective of this study was to investigate an indirect method of measuring the average junction temperature of a white organic light-emitting diode (OLED) based on temperature sensitivity differences in the radiant power emitted by individual emitter materials (i.e., "blue," "green," and "red"). The measured spectral power distributions (SPDs) of the white OLED as a function of temperature showed amplitude decrease as a function of temperature in the different spectral bands, red, green, and blue. Analyzed data showed a good linear correlation between the integrated radiance for each spectral band and the OLED panel temperature, measured at a reference point on the back surface of the panel. The integrated radiance ratio of the spectral band green compared to red, (G/R), correlates linearly with panel temperature. Assuming that the panel reference point temperature is proportional to the average junction temperature of the OLED panel, the G/R ratio can be used for estimating the average junction temperature of an OLED panel.

  5. OLED-based sensor array for simultaneous monitoring of multiple analytes

    NASA Astrophysics Data System (ADS)

    Cai, Yuankun; Shinar, Ruth; Zhou, Zhaoqun; Shinar, Joseph

    2007-09-01

    A compact, photoluminescence (PL)-based sensor array, utilizing tris(quinolinolate) Al OLED pixels as the excitation sources, for sequential or simultaneous monitoring of dissolved oxygen (DO), glucose, lactate, and alcohol, is described. The DO is monitored through its effect on the PL lifetime of the oxygen-sensitive dye Pt octaethylporphyrin (PtOEP) embedded in a polystyrene film. The other analytes are monitored through their oxidation, catalyzed by an appropriate oxidase, which reduces the amount of DO in their vicinity. The OLED pixels are fabricated on a glass substrate; each pixel is typically 2×2 mm2, with a 2 mm gap between the pixels. Two OLED pixels are associated with the detection of each of the analytes. The pixels are individually addressable, enabling consecutive detection of the different analytes within a few minutes utilizing a single photodetector (PD). Simultaneous detection is achieved by using an array of PDs. The OLED-based sensing array is compact and uniquely simple in its ease of fabrication and integration. Its performance attributes are comparable to those obtained for a single analyte using any excitation source. The potential of small-size, multi-color OLED pixel arrays for multianalyte detection is also discussed.

  6. Active matrix organic light emitting diode (OLED)-XL life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Ghosh, Amalkumar P.; Prache, Olivier

    2008-04-01

    OLED displays have been known to exhibit high levels of performance with regards to contrast, response time, uniformity, and viewing angle, but a lifetime improvement has been perceived to be essential for broadening the applications of OLED's in the military and in the commercial market. As a result of this need, the US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to improve the lifetime of OLED displays. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications, and RDECOM CERDEC NVESD ran life tests on these displays, finding over 200% lifetime improvement for the XL devices over the standard displays. Early results were published at the 2007 SPIE Defense and Security Symposium. Further life testing of XL and standard devices at ambient conditions and at high temperatures will be presented this year along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be needed. This is a continuation of the paper "Life test results of OLED-XL long-life devices for use in active matrix organic light emitting diode (AMOLED) displays for head mounted applications" presented at SPIE DSS in 2007.

  7. Organic Light-Emitting Diodes (OLEDs) and Optically-Detected Magnetic Resonance (ODMR) studies on organic materials

    NASA Astrophysics Data System (ADS)

    Cai, Min

    Organic semiconductors have evolved rapidly over the last decades and currently are considered as the next-generation technology for many applications, such as organic light-emitting diodes (OLEDs) in flat-panel displays (FPDs) and solid state lighting (SSL), and organic solar cells (OSCs) in clean renewable energy. This dissertation focuses mainly on OLEDs. Although the commercialization of the OLED technology in FPDs is growing and appears to be just around the corner for SSL, there are still several key issues that need to be addressed: (1) the cost of OLEDs is very high, largely due to the costly current manufacturing process; (2) the efficiency of OLEDs needs to be improved. This is vital to the success of OLEDs in the FPD and SSL industries; (3) the lifetime of OLEDs, especially blue OLEDs, is the biggest technical challenge. All these issues raise the demand for new organic materials, new device structures, and continued lower-cost fabrication methods. In an attempt to address these issues, we used solution-processing methods to fabricate highly efficient small molecule OLEDs (SMOLEDs); this approach is cost-effective in comparison to the more common thermal vacuum evaporation. We also successfully made efficient indium tin oxide (ITO)-free SMOLEDs to further improve the efficiency of the OLEDs. We employed the spin-dependent optically-detected magnetic resonance (ODMR) technique to study the luminescence quenching processes in OLEDs and organic materials in order to understand the intrinsic degradation mechanisms. We also fabricated polymer LEDs (PLEDs) based on a new electron-accepting blue-emitting polymer and studied the effect of molecular weight on the efficiency of PLEDs. All these studies helped us to better understand the underlying relationship between the organic semiconductor materials and the OLEDs' performance, and will subsequently assist in further enhancing the efficiency of OLEDs. With strongly improved device performance (in addition to

  8. Purification and Characterization of OleA from Xanthomonas campestris and Demonstration of a Non-decarboxylative Claisen Condensation Reaction*

    PubMed Central

    Frias, Janice A.; Richman, Jack E.; Erickson, Jasmine S.; Wackett, Lawrence P.

    2011-01-01

    OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C8 to C16 in length. With limiting myristoyl-CoA (C14), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [14C]myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reaction in the first step of the olefin biosynthetic pathway previously found to be present in at least 70 different bacterial strains. PMID:21266575

  9. Purification and Characterization of OleA from Xanthomonas campestris and Demonstration of a Non-decarboxylative Claisen Condensation Reaction

    SciTech Connect

    Frias, JA; Richman, JE; Erickson, JS; Wackett, LP

    2011-03-25

    OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C(8) to C(16) in length. With limiting myristoyl-CoA (C(14)), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [(14)C] myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reaction in the first step of the olefin biosynthetic pathway previously found to be present in at least 70 different bacterial strains.

  10. Causes of difficulty in duration judgments: comment on Francuz and Oleś (2011).

    PubMed

    Okazaki, Yoshihiro S; Matsuda, Fumiko; Fumiko, Matsuda

    2012-12-01

    In 2011, Okazaki and Matsuda showed in studies that college students could not correctly estimate the duration of movement of two objects. Fancuz and Oleś (2011) proposed two explanations of the observed task difficulty. First, they suggested that the cause of the difficulty for the duration judgments involved the experimental procedure, which may have overloaded the cognitive capacities of these students. This study presents results that indicate there was no overload. Second, because the training was intended to improve response accuracy, but it failed to significantly increase accuracy rates, Fancuz and Oleś (2011) suggested there was insufficient time for learning about the task. With respect to these results, Fancuz and Oleś (2011) are correct in pointing out that the training duration could be an issue.

  11. OLED Fundamentals: Materials, Devices, and Processing of Organic Light-Emitting Diodes

    SciTech Connect

    Blochwitz-Nimoth, Jan; Bhandari, Abhinav; Boesch, Damien; Fincher, Curtis R.; Gaspar, Daniel J.; Gotthold, David W.; Greiner, Mark T.; Kido, Junji; Kondakov, Denis; Korotkov, Roman; Krylova, Valentina A.; Loeser, Falk; Lu, Min-Hao; Lu, Zheng-Hong; Lussem, Bjorn; Moro, Lorenza; Padmaperuma, Asanga B.; Polikarpov, Evgueni; Rostovtsev, Vsevolod V.; Sasabe, Hisahiro; Silverman, Gary; Thompson, Mark E.; Tietze, Max; Tyan, Yuan-Sheng; Weaver, Michael; Xin , Xu; Zeng, Xianghui

    2015-05-26

    What is an organic light emitting diode (OLED)? Why should we care? What are they made of? How are they made? What are the challenges in seeing these devices enter the marketplace in various applications? These are the questions we hope to answer in this book, at a level suitable for knowledgeable non-experts, graduate students and scientists and engineers working in the field who want to understand the broader context of their work. At the most basic level, an OLED is a promising new technology composed of some organic material sandwiched between two electrodes. When current is passed through the device, light is emitted. The stack of layers can be very thin and has many variations, including flexible and/or transparent. The organic material can be polymeric or composed small molecules, and may include inorganic components. The electrodes may consist of metals, metal oxides, carbon nanomaterials, or other species, though of course for light to be emitted, one electrode must be transparent. OLEDs may be fabricated on glass, metal foils, or polymer sheets (though polymeric substrates must be modified to protect the organic material from moisture or oxygen). In any event, the organic material must be protected from moisture during storage and operation. A control circuit, the exact nature of which depends on the application, drives the OLED. Nevertheless, the control circuit should have very stable current control to generate uniform light emission. OLEDs can be designed to emit a single color of light, white light, or even tunable colors. The devices can be switched on and off very rapidly, which makes them suitable for displays or for general lighting. Given the amazing complexity of the technical and design challenges for practical OLED applications, it is not surprising that applications are still somewhat limited. Although organic electroluminescence is more than 50 years old, the modern OLED field is really only about half that age – with the first high

  12. Differences between vacuum-deposited and spin-coated amorphous films of OLED materials (presentation video)

    NASA Astrophysics Data System (ADS)

    Yokoyama, Daisuke; Shibata, Maki

    2014-10-01

    To realize low-cost fabrication processes for high-performance OLED displays and lighting panels, the understanding of solution-processed films and devices is becoming more important nowadays. However, differences between vacuum- and solution-processed films have not been sufficiently discussed, and they are sometimes regarded as identical. In this presentation, we show and discuss the important differences between physical properties of vacuum-deposited and spin-coated films of small-molecule OLED materials, especially focusing on the differences in film densities and molecular orientation. Since they are fundamental factors affecting both electrical and optical properties of amorphous films used in OLEDs, we should consider their differences carefully when discussing device performances in detail.

  13. Advances in OLED/OPD-based spectrometer on-a-chip

    NASA Astrophysics Data System (ADS)

    Manna, Eeshita; Fungura, Fadzai; Shinar, Joseph; Shinar, Ruth

    2015-08-01

    We describe ongoing advances toward achieving an integrated all-organic spectrometer on a chip. To this end, 2-dimensional combinatorial arrays of microcavity (μc) organic light emitting diodes (OLEDs) with systematically varying optical cavity lengths were fabricated on a single chip by changing the thickness of different organic and/or spacer layers sandwiched between the two metal electrodes. The latter, one of which is semitransparent, form the cavity. The tunable and narrower emissions from the μcOLEDs serve as excitation sources of varying wavelength for monitoring light absorption or emission. For each wavelength, the light from the μcOLED is partially absorbed by the sample under study and the transmitted light (or the light emitted by an electronically excited sample) is detected by a photodetector (PD). To obtain a compact monitor, an organic PD (OPD) is fabricated and integrated with the μcOLED array. We show the potential of encompassing a broader wavelength range by using μcOLEDs based on different emitting layers. The OPD used to realize the first all-organic integrated spectrometer described here is based on P3HT:PCBM, though more sensitive OPDs we utilized in sensing applications are expected to improve the spectrometers' performance. The utility of this all-organic μcOLED/OPD spectrometer is shown for monitoring the absorption spectra of P3HT and Alexa Fluor 405 films. The results show excellent agreement with the absorption spectra obtained with a commercial Ocean Optics spectrometer.

  14. Investigation of the Representation of OLEs and Terrain Effects within the Coastal Zone in the EDMF Parameterization Scheme: An Airborne Doppler Wind Lidar Perspective

    DTIC Science & Technology

    2015-10-21

    Section 1, we also investigated the possibility of modifying the EDMF to incorporate the flux transport due to PBL -scale OLEs that are not solely...inconsistent with OLE dependence on full PBL profiles 2.2 Modeling of OLEs and utilization in EDMF (UW lead) The standard eddy-diffusivity mass-flux (EDMF...parameterization is designed to capture the non-local planetary boundary layer ( PBL ) transport induced by organized large eddies (OLE) in strongly

  15. Organic Light-Emitting Diodes (OLEDs) and Optically-Detected Magnetic Resonance (ODMR) studies on organic materials

    SciTech Connect

    Cai, Min

    2011-01-01

    Organic semiconductors have evolved rapidly over the last decades and currently are considered as the next-generation technology for many applications, such as organic light-emitting diodes (OLEDs) in flat-panel displays (FPDs) and solid state lighting (SSL), and organic solar cells (OSCs) in clean renewable energy. This dissertation focuses mainly on OLEDs. Although the commercialization of the OLED technology in FPDs is growing and appears to be just around the corner for SSL, there are still several key issues that need to be addressed: (1) the cost of OLEDs is very high, largely due to the costly current manufacturing process; (2) the efficiency of OLEDs needs to be improved. This is vital to the success of OLEDs in the FPD and SSL industries; (3) the lifetime of OLEDs, especially blue OLEDs, is the biggest technical challenge. All these issues raise the demand for new organic materials, new device structures, and continued lower-cost fabrication methods. In an attempt to address these issues, we used solution-processing methods to fabricate highly efficient small molecule OLEDs (SMOLEDs); this approach is costeffective in comparison to the more common thermal vacuum evaporation. We also successfully made efficient indium tin oxide (ITO)-free SMOLEDs to further improve the efficiency of the OLEDs. We employed the spin-dependent optically-detected magnetic resonance (ODMR) technique to study the luminescence quenching processes in OLEDs and organic materials in order to understand the intrinsic degradation mechanisms. We also fabricated polymer LEDs (PLEDs) based on a new electron-accepting blue-emitting polymer and studied the effect of molecular weight on the efficiency of PLEDs. All these studies helped us to better understand the underlying relationship between the organic semiconductor materials and the OLEDs’ performance, and will subsequently assist in further enhancing the efficiency of OLEDs. With strongly improved device performance (in addition to

  16. Enhanced light extraction efficiency of OLEDs with quasiperiodic diffraction grating layer.

    PubMed

    Lim, Tae-Bin; Cho, Kwan Hyun; Kim, Yong-Hoon; Jeong, Yong-Cheol

    2016-08-08

    We presented enhanced light extraction efficiency of organic light emitting diodes (OLEDs) cells with a nano-sized diffraction grating layer. Various diffraction gratings of different morphologies including linear, cubic, hexagonal and quasiperiodic patterns were fabricated by multiplexing light interference exposure on an azobenzene thin film. The effect of diffraction grating layer on device performances including luminous properties and quantum efficiency was investigated. In contrast to periodic grating patterns, the quasiperiodic structures leading broadband light extraction resulted in improved external quantum efficiency and power efficiency by 73% and 63%, respectively, compared to conventional OLED with flat surface of glass substrate.

  17. Enhanced color purity of blue OLEDs based on well-design structure

    NASA Astrophysics Data System (ADS)

    Du, Qianqian; Wang, Wenjun; Li, Shuhong; Wang, Qingru; Xia, Shuzhen; Zhang, Bingyuan; Wang, Minghong; Fan, Quli

    2016-09-01

    We have fabricated blue organic light-emitting devices (OLEDs) with higher color purity and stability by optimizing the structure of the Glass/ITO/NPB(50 nm)/ BCzVBi (30 nm)/ TPBi (x nm)/Alq3(20 nm)/LiF/Al. The results show that the introducing of hole blocking layer(HBL) TPBi greatly can improve not only the color purity but the color stability, which owe to its higher the Highest Occupied Molecular Orbital (HOMO) energy levels of 6.2 eV. We expect our work will be useful to optimizing the blue OLEDs structure to enhancing the color property.

  18. Color tunability in multilayer OLEDs based on DCM and DPVBi as emitting materials

    NASA Astrophysics Data System (ADS)

    Petrova, P. K.; Ivanov, P. I.; Tomova, R. L.

    2014-05-01

    We report studies on the color tunability of a novel type of multilayer organic light-emitting diodes (OLEDs) based on three emitting materials: DCM (4-(Dicyanomethylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran) as a red emitter, DPVBi [4,4'-Bis(2,2-diphenylvinyl)-1,1'-biphenyl] as a blue emitter and zinc bis(2-(2-hydroxyphenyl) benzothiazole) (Zn(BTz)2) as a yellow emitter, and an electron transporting layer. We established that the positions and thicknesses of the different emitting layers determine the efficiencies, luminance and color of the light emitted by the OLEDs.

  19. Sublimation not an innocent technique: a case of bis-cyclometalated iridium emitter for OLED.

    PubMed

    Baranoff, Etienne; Suàrez, Stéphane; Bugnon, Philippe; Barolo, Claudia; Buscaino, Roberto; Scopelliti, Rosario; Zuppiroli, Libero; Graetzel, Michael; Nazeeruddin, Md K

    2008-08-04

    Isomerization of a neutral bis-cyclometalated iridium(III) complex has been observed for the first time during the preparation of vacuum-processed organic light-emitting devices (OLEDs) and reproduced in solution. Isolation of the isomer revealed a cis organization of the two pyridine rings of the cyclometalating ligands. Photophysical studies show very similar emission properties of the two isomers. However, due to in situ isomerization, it is only possible to prepare vacuum-processed OLED devices having a mixture of isomers.

  20. Formylated chloro-bridged iridium(III) dimers as OLED materials: opening up new possibilities.

    PubMed

    Wong, Michael Y; Xie, Guohua; Tourbillon, Clarisse; Sandroni, Martina; Cordes, David B; Slawin, Alexandra M Z; Samuel, Ifor D W; Zysman-Colman, Eli

    2015-05-14

    In this study, a series of four formyl-substituted chloro-bridged iridium(iii) dimers were prepared. Their absorption, photophysical and electrochemical properties were studied in dichloromethane solution. It was found that as the formyl content increased on the cyclometalating ligands, emission unexpectedly became brighter. Organic light-emitting diodes (OLEDs) were fabricated using each of these iridium dimers as the emitter. The OLED fabricated using the brightest of the series, 2b, as the dopant afforded a decent external quantum efficiency (EQE) of 2.6%. This suggests that chloro-bridged iridium dimers are potential candidates as solid-state emitters.

  1. Physical process in OLED architectures with transparent carbon nanotube sheets as electrodes

    NASA Astrophysics Data System (ADS)

    Ovalle Robles, Raquel

    There has been a great deal of activity in the development of organic light emitting diodes (OLED's) and polymeric light emitting diodes (PLED's). Research in OLEDs and PLEDs have been having a significant development over the last few years towards commercialization, extended life time, stability, efficiency and new fabrication processes suitable for mass production are some of the topics. The potential for commercialization is high due to their low operating voltage (typically between 2.5 to 5 volts), their high brightness and their ease to process. They are light weight and can be flexible. Furthermore, these devices can be easily color tune to produce red, green and blue colors. Research in this type of electroluminescence devices has advanced rapidly and device prototypes now meet realistic specifications for applications. By proper device engineering these devices can achieve high electroluminescence efficiencies and lifetimes. In this research project we present several methods and procedures that we developed and use to produce OLEDs and PLEDs. We have incorporated quantum dots into OLEDs as emissive dopants that contribute to the control of the spectral distribution of emitted light allowing the production of white OLEDs using both a multilayer structure with emission from multiple layers and a bilayer structure with emission from only the quantum dots. We have also produced PLED devices with a new family of novel PPV polymers achieving high bright efficient devices. OLED structures with transparent carbon nanotube sheets, obtained by dry drawing from a CVD-grown forest have been produced. The devices shown to be very bright and the MCNT sheets are efficient hole-injecting anodes for OLEDs Also, for flexible display applications, there is a need for high strength, flexible materials which can be deposited as transparent films and can act as hole injectors for organic films. By using a hybrid ITO/MWCNT anode onto flexible substrates an enhancement of the

  2. Enhanced light extraction in ITO-free OLEDs using double-sided printed electrodes

    NASA Astrophysics Data System (ADS)

    Reboud, Vincent; Khokhar, Ali Z.; Sepúlveda, Borja; Dudek, Damian; Kehoe, Tim; Cuffe, John; Kehagias, Nikolaos; Lira-Cantu, Mónica; Gadegaard, Nikolaj; Grasso, Valentina; Lambertini, Vito; Sotomayor Torres, Clivia M.

    2012-05-01

    We show how nanoimprint lithographic techniques are particularly suited for the realization of OLED device structures. We tested them to realize nanopatterned metallic electrodes containing photonic crystals to couple the light out and plasmonic crystals showing extraordinary transmission. At similar current densities, a two-fold electroluminescence is achieved with devices having double-sided structured metallic electrodes as compared to a control OLED with an ITO anode. The use of combined nanoimprint lithography processes has the potential to expand the performance range of various organic optoelectronic devices.

  3. Investigation of cross-linking characteristics of novel hole-transporting materials for solution-processed phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Lee, Jaemin; Ameen, Shahid; Lee, Changjin

    2016-04-01

    After the success of commercialization of the vacuum-evaporated organic light-emitting diodes (OLEDs), solutionprocessing or printing of OLEDs are currently attracting much research interests. However, contrary to various kinds of readily available vacuum-evaporable OLED materials, the solution-processable OLED materials are still relatively rare. Hole-transporting layer (HTL) materials for solution-processed OLEDs are especially limited, because they need additional characteristics such as cross-linking to realize multilayer structures in solution-processed OLEDs, as well as their own electrically hole-transporting characteristics. The presence of such cross-linking characteristics of solutionprocessable HTL materials therefore makes them more challenging in the development stage, and also makes them essence of solution-processable OLED materials. In this work, the structure-property relationships of thermally crosslinkable HTL materials were systematically investigated by changing styrene-based cross-linking functionalities and modifying the carbazole-based hole-transporting core structures. The temperature dependency of the cross-linking characteristics of the HTL materials was systematically investigated by the UV-vis. absorption spectroscopy. The new HTL materials were also applied to green phosphorescent OLEDs, and their device characteristics were also investigated based on the chemical structures of the HTL materials. The device configuration was [ITO / PEDOT:PSS / HTL / EML / ETL / CsF / Al]. We found out that the chemical structures of the cross-linking functionalities greatly affect not only the cross-linking characteristics of the resultant HTL materials, but also the resultant OLED device characteristics. The increase of the maximum luminance and efficiency of OLEDs was evident as the cross-linking temperature decreases from higher than 200°C to at around 150°C.

  4. Optically detected magnetic resonance (ODMR) studies of trions in organic light-emitting materials and OLEDs and their possible relation to long-term OLED degradation

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Cai, Min; Xiao, Teng; Hellerich, Emily; Shinar, Joseph

    2008-08-01

    Some recent photoluminescence (PL)- and electroluminescence (EL)-detected magnetic resonance (PLDMR and ELDMR, respectively) studies of the negative (PL- and EL-quenching) spin 1/2 resonance are reviewed. These include the resonances in poly[2-(N-carbazolyl)-5-(2'-ethyl)-hexoxy-1,4-phenylenevinylene] (CzEh-PPV) films, rubrene films, tris(quinolinolate) Al (Alq3) OLEDs, rubrene-doped Alq3 OLEDs, and fac tris(2-phenylpyridine) iridium [Ir(ppy3)]-doped poly(N-vinyl carbazole) (PVK) polymer LEDs (PLEDs). The resonances are all assigned to quenching of SEs by trions, which are bipolarons stabilized by a counterpolaron or counterion. As bipolarons are spinless, their formation from two like-charged polarons is spin-dependent, and hence enhanced at resonance. This enhanced formation, and the resulting enhanced quenching of SEs, yields the negative spin 1/2 PLDMR and ELDMR. As previously shown, since trion formation also reduces the mobility of the trapped carriers, this process also results in a negative spin 1/2 electrical current-detected magnetic resonance (EDMR). Importantly, since the counterpolaron is usually trapped, e.g., at organic/cathode or organic/organic interfaces, or at impurity sites such the oxygen center in rubrene, it is suspected that the trions might be responsible for the long term degradation of OLEDs and PLEDs associated with abrupt junctions or impurities.

  5. Permanent polarization and charge distribution in organic light-emitting diodes (OLEDs): Insights from near-infrared charge-modulation spectroscopy of an operating OLED

    SciTech Connect

    Marchetti, Alfred P.; Haskins, Terri L.; Young, Ralph H.; Rothberg, Lewis J.

    2014-03-21

    Vapor-deposited Alq{sub 3} layers typically possess a strong permanent electrical polarization, whereas NPB layers do not. (Alq{sub 3} is tris(8-quinolinolato)aluminum(III); NPB is 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl.) The cause is a net orientation of the Alq{sub 3} molecules with their large dipole moments. Here we report on consequences for an organic light-emitting diode (OLED) with an NPB hole-transport layer and Alq{sub 3} electron-transport layer. The discontinuous polarization at the NPB|Alq{sub 3} interface has the same effect as a sheet of immobile negative charge there. It is more than compensated by a large concentration of injected holes (NPB{sup +}) when the OLED is running. We discuss the implications and consequences for the quantum efficiency and the drive voltage of this OLED and others. We also speculate on possible consequences of permanent polarization in organic photovoltaic devices. The concentration of NPB{sup +} was measured by charge-modulation spectroscopy (CMS) in the near infrared, where the NPB{sup +} has a strong absorption band, supplemented by differential-capacitance and current-voltage measurements. Unlike CMS in the visible, this method avoids complications from modulation of the electroluminescence and electroabsorption.

  6. Efficient, deep-blue TADF-emitters for OLED display applications (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Volz, Daniel; Baumann, Thomas

    2016-09-01

    Currently, the mobile display market is strongly shifting towards AMOLED technology, in order to enable curved and flexible displays. This leads to a growing demand for highly efficient OLED emitters to reduce the power consumption and increase display resolution at the same time. While highly efficient green and red OLEDs already found their place in commercial OLED-displays, the lack of efficient blue emitters is still an issue. Consequently, the active area for blue is considerably larger than for green and red pixels, to make up for the lower efficiency. We intend to close this efficiency-gap with novel emitters based on thermally activated delayed fluorescence (TADF) technology. Compared to state-of-the-art fluorescent dopants, the efficiency of TADF-emitters is up to four times higher. At the same time, it is possible to design them in a way to maintain deep blue emission, i.e. CIE y < 0.2. These aspects are relevant to produce efficient high resolution AMOLED displays. Apart from these direct customer benefits, our TADF technology does not contain any rare elements, which allows for the fabrication of sustainable OLED technology. In this work, we highlight one of our recently developed blue TADF materials. Basic material properties as well as first device results are discussed. In a bottom-emitting device, a CIEx/CIEy coordinate of (0.16/0.17) was achieved with efficiency values close to 20% EQE.

  7. To enhancement illuminance efficiency of OLED by thin film included microparticle

    NASA Astrophysics Data System (ADS)

    Chiu, Chuang-Hung; Chien, Chao-Heng; Lee, Jen-Chi; Chien, Wei-Cheng

    2015-09-01

    An optical thin film was provided to address light illuminance efficiency of OLED up to 80%. A polymer material was used as a film base material which could avoid the influence of total reflection angle. One kinds of oxidized metal micro-particles was chosen to dope inside the optical thin film and to increase scattering and refractive effect.

  8. Research and hardware implementation of image enhancement algorithm in OLED system

    NASA Astrophysics Data System (ADS)

    Xu, Meihua; Li, Ke; Fan, Yule

    2009-11-01

    During the process of generation and transmission, images will be influenced by the performance of imaging system, quantization noise or some other actors. The image will appear some phenomenons like clarity decrease and low contrast. For the sake of improving the picture quality in OLED system, time sequence control logic and hardware of the whole OLED system were implemented based on the detailed analysis of OLED panel electrical characteristics and various gray scale scanning principles. Sub-field scanning working mode is adopted in the design. Gray scale is 64 and vertical sweep frequency is 60Hz~100Hz.FPGA is the core control device in the whole system, the DVI decoded signal is processed. The design realizes the real-time video display on OLED. The utilization of parameters regulated homomorphic filtering technology is studied to improve the quality of color image. At first, the high and low frequency parts are departed with the help of illumination reflectance model.Then the digital image is processed with approximate high-pass filter, the simplified filtering algorithm made a compromise solution between the complex of hardware implementation and image quality. In the end, by the frequency domain inverse transformation, images got enhanced. The experiment results show that the particular information extrudes and the whole visual effect is improved after the process.

  9. Mutagenesis and redox partners analysis of the P450 fatty acid decarboxylase OleTJE.

    PubMed

    Fang, Bo; Xu, Huifang; Liu, Yi; Qi, Fengxia; Zhang, Wei; Chen, Hui; Wang, Cong; Wang, Yilin; Yang, Wenxia; Li, Shengying

    2017-03-09

    The cytochrome P450 enzyme OleTJE from Jeotgalicoccus sp. ATCC 8456 is capable of converting free long-chain fatty acids into α-alkenes via one-step oxidative decarboxylation in presence of H2O2 as cofactor or using redox partner systems. This enzyme has attracted much attention due to its intriguing but unclear catalytic mechanism and potential application in biofuel production. Here, we investigated the functionality of a select group of residues (Arg245, Cys365, His85, and Ile170) in the active site of OleTJE through extensive mutagenesis analysis. The key roles of these residues for catalytic activity and reaction type selectivity were identified. In addition, a range of heterologous redox partners were found to be able to efficiently support the decarboxylation activity of OleTJE. The best combination turned out to be SeFdx-6 (ferredoxin) from Synechococcus elongatus PCC 7942 and CgFdR-2 (ferredoxin reductase) from Corynebacterium glutamicum ATCC 13032, which gave the highest myristic acid conversion rate of 94.4%. Moreover, Michaelis-Menton kinetic parameters of OleTJE towards myristic acid were determined.

  10. Catalytic strategy for carbon−carbon bond scission by the cytochrome P450 OleT

    PubMed Central

    Grant, Job L.; Mitchell, Megan E.; Makris, Thomas Michael

    2016-01-01

    OleT is a cytochrome P450 that catalyzes the hydrogen peroxide-dependent metabolism of Cn chain-length fatty acids to synthesize Cn-1 1-alkenes. The decarboxylation reaction provides a route for the production of drop-in hydrocarbon fuels from a renewable and abundant natural resource. This transformation is highly unusual for a P450, which typically uses an Fe4+−oxo intermediate known as compound I for the insertion of oxygen into organic substrates. OleT, previously shown to form compound I, catalyzes a different reaction. A large substrate kinetic isotope effect (≥8) for OleT compound I decay confirms that, like monooxygenation, alkene formation is initiated by substrate C−H bond abstraction. Rather than finalizing the reaction through rapid oxygen rebound, alkene synthesis proceeds through the formation of a reaction cycle intermediate with kinetics, optical properties, and reactivity indicative of an Fe4+−OH species, compound II. The direct observation of this intermediate, normally fleeting in hydroxylases, provides a rationale for the carbon−carbon scission reaction catalyzed by OleT. PMID:27555591

  11. Improving the viewing angle properties of microcavity OLEDs by using dispersive gratings.

    PubMed

    Choy, Wallace C H; Ho, C Y

    2007-10-01

    The changes of emission peak wavelength and angular intensity with viewing angles have been issues for the use of microcavity OLEDs. We will investigate Distributed Bragg Gratings (DBRs) constructed from largely dispersive index materials for reducing the viewing angle dependence. A DBR stack mirror, aiming at a symmetric structure and less number of grating period for a practical fabrication, is studied to achieve a chirp-featured grating for OLEDs with blue emission peak of 450nm. For maximizing the compensation of the viewing angle dependence, the effects of dispersive index, grating structure, thickness of each layer of the grating, grating period and chirp will be comprehensively investigated. The contributions of TE and TM modes to the angular emission power will be analyzed for the grating optimization, which have not been expressed in detail. In studying the light emission of OLEDs, we will investigate the Purcell effect which is important but has not been properly considered. Our results show that with a proper design of the DBR, not only a wider viewing angle can be achieved but also the color purity of OLEDs can be improved.

  12. Rearrangement of cyclotriveratrylene (CTV) diketone: 9,10-diarylanthracenes with OLED applications.

    PubMed

    Sarsah, Samuel R S; Lutz, Marlon R; Zeller, Matthias; Crumrine, David S; Becker, Daniel P

    2013-03-01

    Electroluminescent 9,10-diaryl anthracenes have been shown to be promising host and hole-transporting materials in organic electroluminescence due to their high thermal stability, electrochemical reversibility, and wide band gap useful for organic light-emitting diodes (OLEDs), especially blue OLEDs. Oxidation of cyclotriveratrylene (CTV) to the corresponding diketone and subsequent bromination resulted in an unexpected rearrangement to a highly functionalized 9-aryl-10-bromoanthracene derivative, which was employed in Suzuki couplings to synthesize a series of 9,10-diaryl compounds that are structural analogues of anthracene derivatives used in the preparation of OLEDs but are more highly functionalized, including electron-donating methoxy groups in addition to substitution by a carboxylic acid moiety. The UV/fluorescence solution spectra show strong emissions at 446, 438, and 479 nm, respectively, for the anthracene 10-phenyl, 10-naphthyl, and 10-pyrenyl adducts containing a benzoic acid functional group, whereas the analogues bearing the hydroxymethylene moiety from reduction of the benzoic acid to the corresponding alcohols gave much shorter emission wavelengths of 408, 417, and 476 nm, respectively, and had somewhat higher quantum yields, suggesting they are better candidates for OLED applications.

  13. Dual enhancement of electroluminescence efficiency and operational stability by rapid upconversion of triplet excitons in OLEDs

    PubMed Central

    Furukawa, Taro; Nakanotani, Hajime; Inoue, Munetomo; Adachi, Chihaya

    2015-01-01

    Recently, triplet harvesting via a thermally activated delayed fluorescence (TADF) process has been established as a realistic route for obtaining ultimate internal electroluminescence (EL) quantum efficiency in organic light-emitting diodes (OLEDs). However, the possibility that the rather long transient lifetime of the triplet excited states would reduce operational stability due to an increased chance for unwarranted chemical reactions has been a concern. Herein, we demonstrate dual enhancement of EL efficiency and operational stability in OLEDs by employing a TADF molecule as an assistant dopant and a fluorescent molecule as an end emitter. The proper combination of assistant dopant and emitter molecules realized a “one-way” rapid Förster energy transfer of singlet excitons from TADF molecules to fluorescent emitters, reducing the number of cycles of intersystem crossing (ISC) and reverse ISC in the TADF molecules and resulting in a significant enhancement of operational stability compared to OLEDs with a TADF molecule as the end emitter. In addition, we found that the presence of this rapid energy transfer significantly suppresses singlet-triplet annihilation. Using this finely-tuned rapid triplet-exciton upconversion scheme, OLED performance and lifetime was greatly improved. PMID:25673259

  14. Mutagenesis and redox partners analysis of the P450 fatty acid decarboxylase OleTJE

    PubMed Central

    Fang, Bo; Xu, Huifang; Liu, Yi; Qi, Fengxia; Zhang, Wei; Chen, Hui; Wang, Cong; Wang, Yilin; Yang, Wenxia; Li, Shengying

    2017-01-01

    The cytochrome P450 enzyme OleTJE from Jeotgalicoccus sp. ATCC 8456 is capable of converting free long-chain fatty acids into α-alkenes via one-step oxidative decarboxylation in presence of H2O2 as cofactor or using redox partner systems. This enzyme has attracted much attention due to its intriguing but unclear catalytic mechanism and potential application in biofuel production. Here, we investigated the functionality of a select group of residues (Arg245, Cys365, His85, and Ile170) in the active site of OleTJE through extensive mutagenesis analysis. The key roles of these residues for catalytic activity and reaction type selectivity were identified. In addition, a range of heterologous redox partners were found to be able to efficiently support the decarboxylation activity of OleTJE. The best combination turned out to be SeFdx-6 (ferredoxin) from Synechococcus elongatus PCC 7942 and CgFdR-2 (ferredoxin reductase) from Corynebacterium glutamicum ATCC 13032, which gave the highest myristic acid conversion rate of 94.4%. Moreover, Michaelis-Menton kinetic parameters of OleTJE towards myristic acid were determined. PMID:28276499

  15. Dependence of Organic Interlayer Diffusion on Glass-Transition Temperature in OLEDs.

    PubMed

    McEwan, Jake A; Clulow, Andrew J; Nelson, Andrew; Yepuri, Nageshwar Rao; Burn, Paul L; Gentle, Ian R

    2017-04-26

    Organic light-emitting diodes (OLEDs) are subject to thermal stress from Joule heating and the external environment. In this work, neutron reflectometry (NR) was used to probe the effect of heat on the morphology of thin three-layer organic films comprising materials typically found in OLEDs. It was found that layers within the films began to mix when heated to approximately 20 °C above the glass-transition temperature (Tg) of the material with the lowest Tg. Diffusion occurred when the material with the lowest Tg formed a supercooled liquid, with the rates of interdiffusion of the materials depending on the relative Tg's. If the supercooled liquid formed at a temperature significantly lower than the Tg of the higher-Tg material in the adjacent layer, then pseudo-Fickian diffusion occurred. If the two Tg's were similar, then the two materials can interdiffuse at similar rates. The type and extent of diffusion observed can provide insight into and a partial explanation for the "burn in" often observed for OLEDs. Photoluminescence measurements performed simultaneously with the NR measurements showed that interdiffusion of the materials from the different layers had a strong effect on the emission of the film, with quenching generally observed. These results emphasize the importance of using thermally stable materials in OLED devices to avoid film morphology changes.

  16. Application of Developed APCVD Transparent Conducting Oxides and Undercoat Technologies for Economical OLED Lighting

    SciTech Connect

    Silverman, Gary S.; Bluhm, Martin; Coffey, James; Korotkov, Roman; Polsz, Craig; Salemi, Alexandre; Smith, Robert; Smith, Ryan; Stricker, Jeff; Xu, Chen; Shirazi, Jasmine; Papakonstantopulous, George; Carson, Steve; Hartmann, Sören; Jessen, Frank; Krogmann, Bianaca; Rickers, Christoph; Ruske, Manfred; Schwab, Holger; Bertram, Dietrich

    2011-01-02

    Economics is a key factor for application of organic light emitting diodes (OLED) in general lighting relative to OLED flat panel displays that can handle high cost materials such as indium tin oxide (ITO) or Indium zinc oxide (IZO) as the transparent conducting oxide (TCO) on display glass. However, for OLED lighting to penetrate into general illumination, economics and sustainable materials are critical. The issues with ITO have been documented at the DOE SSL R&D and Manufacturing workshops for the last 5 years and the issue is being exaserbated by export controls from China (one of the major sources of elemental indium). Therefore, ITO is not sustainable because of the fluctuating costs and the United States (US) dependency on other nations such as China. Numerous alternatives to ITO/IZO are being evaluated such as Ag nanoparticles/nanowires, carbon nanotubes, graphene, and other metal oxides. Of these other metal oxides, doped zinc oxide has attracted a lot of attention over the last 10 years. The volume of zinc mined is a factor of 80,000 greater than indium and the US has significant volumes of zinc mined domestically, resulting in the ability for the US to be self-sufficient for this element that can be used in optoelectonic applications. The costs of elemental zinc is over 2 orders of magnitude less than indium, reflecting the relative abundance and availablility of the elements. Arkema Inc. and an international primary glass manufacturing company, which is located in the United States, have developed doped zinc oxide technology for solar control windows. The genesis of this DOE SSL project was to determine if doped zinc oxide technology can be taken from the commodity based window market and translate the technology to OLED lighting. Thus, Arkema Inc. sought out experts, Philips Lighting, Pacific Northwest National Laboratories (PNNL) and National Renewable Research Laboratories (NREL), in OLED devices and brought them into the project. This project had a

  17. Spectrally narrowed leaky waveguide edge emission and transient electrluminescent dynamics of OLEDs

    SciTech Connect

    Zhengqing, Gan

    2010-01-01

    In summary, there are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs. Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication. The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is narrow, and below which the spectrum is broad. The FWHM of spectrum depends on the material of the organic thin films, the thickness of the organic layers, and length of the OLED device. A superlinear relationship between the output intensity of the edge emission and the length of the device was observed, which is probably due to the misalignment of the device edge and the optical fiber detector. The original motivation of this research is for organic semiconductor laser that hasn't been realized due to the extremely high photon absorption in OLED devices. Although we didn't succeed in fabricating an electrically pumped organic laser diode, we made a comprehensive research in edge emission of OLEDs which provides valuable results in understanding light distribution and propagation in OLED devices. Chapter 5 focuses on the second project. A strong spike was observed at the falling edge of a pulse, and a long tail followed. The spike was due to the recombination of correlated charge pair (CCP) created by trapped carriers in guest molecules of the recombination zone. When the bias was turned off, along with the decreasing of electric field in the device, the electric field induced quenching decreases and the recombination rate of the CCP increases which result in the spike. This research project provides a

  18. OLED-based physiologically-friendly very low-color temperature illumination for night

    NASA Astrophysics Data System (ADS)

    Jou, Jwo-Huei; Shen, Shih-Ming; Tang, Ming-Chun; Chen, Pin-Chu; Chen, Szu-Hao; Wang, Yi-Shan; Chen, Chien-Chih; Wang, Ching-Chun; Hsieh, Chun-Yu; Lin, Chin-Chiao; Chen, Chien-Tien

    2012-09-01

    Numerous medical research studies reveal intense white or blue light to drastically suppress at night the secretion of melatonin (MLT), a protective oncostatic hormone. Lighting devices with lower color-temperature (CT) possess lesser MLT suppression effect based on the same luminance, explaining why physicians have long been calling for the development of lighting sources with low CT or free from blue emission for use at night to safeguard human health. We will demonstrate in the presentation the fabrication of OLED devices with very-low CT, especially those with CT much lower than that of incandescent bulbs (2500K) or even candles (2000K). Without any light extraction method, OLEDs with an around 1800K CT are easily obtainable with an efficacy of 30 lm/W at 1,000 nits. To also ensure high color-rendering to provide visual comfort, low CT OLEDs composing long wavelength dominant 5-spectrum emission have been fabricated. While keeping the color-rendering index as high as 85 and CT as low as 2100K, the resulting efficacy can also be much greater than that of incandescent bulbs (15 lm/W), proving these low CT OLED devices to be also capable of being energy-saving and high quality. The color-temperature can be further decreased to 1700K or lower upon removing the undesired short wavelength emission but on the cost of losing some color rendering index. It is hoped that the devised energy-saving, high quality low CT OLED could properly echo the call for a physiologically-friendly illumination for night, and more attention could be drawn to the development of MLT suppression-less non-white light.

  19. Enhancement of light extraction efficiency of OLEDs using Si₃N₄-based optical scattering layer.

    PubMed

    Park, Sang-Jun; Kim, Yang Doo; Lee, Ho Won; Yang, Hyung Jin; Cho, Joong-Yeon; Kim, Young Kwan; Lee, Heon

    2014-05-19

    An optical scattering layer, consisting of a Si3N4 nano-pillar array and a spin-coated hydrogen silsesquioxane (HSQ) planarization layer, was introduced to an organic light-emitting diode (OLED) substrate to increase the out-coupling efficiency. After plasma enhanced chemical vapor deposition (PECVD) of the Si3N4 layer, the nano-pillar array was created using nanoimprint lithography and reactive ion etching. As the Si3N4 pillar array has a refractive index of 2.0, photons generated in the organic layer are scattered by the Si3N4 structures and thus have a higher chance of being emitted from the device. The spin-coated HSQ planarization layer produces a flat substrate, which is essential for depositing a uniform organic material layer and assuring the electric conductivity of the transparent conducting oxide (TCO) layer. In this study, Si3N4 nano-structures with a height of 100 or 300 nm were used to enhance the out-coupling efficiency of the OLED devices. Although the electrical conductivity of the TCO layer deposited on the light scattering layer was slightly degraded, the OLED devices formed with the light scattering layer exhibited a higher luminous power at given electrical power. Consequently, the use of a planarized 300-nm-thick Si3N4 layer increased the external quantum efficiency of the OLED device by 50% at 10,000 cd/m2 compared to the reference OLED device fabricated on a flat glass substrate.

  20. Improved designs for p-i-n OLEDs towards the minimal power loss of devices

    NASA Astrophysics Data System (ADS)

    Qin, Dashan

    2014-05-01

    Currently, the low yield, high power loss, and poor stability of organic light emitting diodes (OLEDs) panels are remaining as the obstacles to the fast growth of the OLED industry, especially for the lighting application. The p-i-n OLEDs have been widely recognized as the promising method to circumvent these bottleneck factors, due to the unique merit of the electrical doping to enable low power loss. In p-i-n OLEDs, the frequently used n-doped electron transport layers (n-ETL1) such as n-BCP, n-Alq3 possess markedly lower conductivities but better capabilities of injecting electrons into ETL such as BCP, Alq3, as compared to another class of n-doped ETLs (n-ETL2), e.g., n-NTCDA, n-PTCDA, n-C60. Thus, in order to minimize the electron loss, we provide the structure of uniting two n-doped layers, cathode/ n-ETL2/ n-ETL1/ ETL. In p-i-n OLEDs, the hole current injected from the single p-doped hole transport layer (p-HTL) into the neat HTL must be limited, because the higher conductivity p-HTL has the higher lying highest occupied molecular orbital (HOMO) level, leading to a larger hole transport energy barrier (φB) at the interface with the neat HTL. Therefore, in order to minimize the hole loss, we suggest the structure of uniting two p-HTLs, anode/ p-HTL2/ p-HTL1/ HTL. The p-HTL2 possesses high-lying HOMO level and thereby high conductivity, decreasing the ohmic loss in the hole conduction; the p-HTL1 features a low-lying HOMO level, reducing the φB.

  1. Electron mobility characterization in OLEDs from ac small signal optical modulation

    NASA Astrophysics Data System (ADS)

    Mu, Haichuan; Reddy, Indrani; Hunt, John; Severs, Phillip; Patil, Shirish

    2010-05-01

    This paper investigates the field dependence of electron mobility in tris(8-hydroxyquinolinato)aluminium (Alq3) and bathocuproine (BCP) through ac small signal optical modulation on green light (ITO/PEDOT/NPD/Alq3/Ba/Ag) and blue light (ITO/PEDOT/NPD/BCP/Alq3/Ba/Ag) OLED. The electroluminescence (EL) transient time delay for the blue light OLED is much longer than for the green one. The electron mobility in BCP was extracted based on a Poole-Frenkel-like equation and EL transient time delay measurement, which is in the range (7-9) × 10-8 cm2 V-1 s-1 at an external electric field of 1530-1830 (V cm-1)1/2, comparable to the results from other published reports (Muckl et al 2000 Synth. Met. 111-112 91; Barth et al 2001 J. Appl. Phys. 89 3711; Nakamura H et al 1996 Int. Symp. on Inorganic and Organic Electroluminescence ed R H Mauch and H-E Gumlich (Berlin: Wissenschaft und Technik) p 95; Xie et al 2002 Appl. Phys. Lett. 80 1477). The difference in EL transient time delay and electron mobility for green and blue light OLEDs was demonstrated by the results of direct modulation. The electron transit time shows similar field dependence in both Alq3 layers in green and blue OLEDs. Unlike Alq3, the field dependence of electron mobility in BCP did not fit the conventional organic semiconductor characteristics μ∞exp(βE1/2), and the excitons formation at the NPD/BCP interface for the blue OLEDs was demonstrated through the EL spectrum.

  2. Maskless RGB color patterning of vacuum-deposited small molecule OLED displays by diffusion of luminescent dopant molecules.

    PubMed

    Kajiyama, Yoshitaka; Kajiyama, Koichi; Aziz, Hany

    2015-06-29

    A maskless RGB color patterning technique based on diffusion of luminescent dopant molecules is proposed here for vacuum-deposited small molecule OLED displays. The proposed maskless color patterning technique enables us to overcome challenging issues in OLED display manufacturing arising from shadow mask limitations. This approach utilizes selective diffusion of luminescent dopant molecules from a donor substrate to an acceptor substrate. Results show that sufficiently high doping levels can be achieved through this technique and that devices with performance similar to those produced by standard co-deposition can be easily produced. Red, green and blue OLEDs are successfully fabricated side by side on one substrate using this technique.

  3. Application of Developed APCVD Transparent Conducting Oxides and Undercoat Technologies for Economical OLED Lighting

    SciTech Connect

    Martin Bluhm; James Coffey; Roman Korotkov; Craig Polsz; Alexandre Salemi; Robert Smith; Ryan Smith; Jeff Stricker; Chen Xu; Jasmine Shirazi; George Papakonstantopulous; Steve Carson; Claudia Goldman; Soren Hartmann; Frank Jessen; Bianca Krogmann; Christoph Rickers; Manfred Ruske; Holger Schwab; Dietrich Bertram

    2011-01-02

    Economics is a key factor for application of organic light emitting diodes (OLED) in general lighting relative to OLED flat panel displays that can handle high cost materials such as indium tin oxide (ITO) or Indium zinc oxide (IZO) as the transparent conducting oxide (TCO) on display glass. However, for OLED lighting to penetrate into general illumination, economics and sustainable materials are critical. The issues with ITO have been documented at the DOE SSL R&D and Manufacturing workshops for the last 5 years and the issue is being exacerbated by export controls from China (one of the major sources of elemental indium). Therefore, ITO is not sustainable because of the fluctuating costs and the United States (US) dependency on other nations such as China. Numerous alternatives to ITO/IZO are being evaluated such as Ag nanoparticles/nanowires, carbon nanotubes, graphene, and other metal oxides. Of these other metal oxides, doped zinc oxide has attracted a lot of attention over the last 10 years. The volume of zinc mined is a factor of 80,000 greater than indium and the US has significant volumes of zinc mined domestically, resulting in the ability for the US to be self-sufficient for this element that can be used in optoelectronic applications. The costs of elemental zinc is over 2 orders of magnitude less than indium, reflecting the relative abundance and availability of the elements. Arkema Inc. and an international primary glass manufacturing company, which is located in the United States, have developed doped zinc oxide technology for solar control windows. The genesis of this DOE SSL project was to determine if doped zinc oxide technology can be taken from the commodity based window market and translate the technology to OLED lighting. Thus, Arkema Inc. sought out experts, Philips Lighting, Pacific Northwest National Laboratories (PNNL) and National Renewable Research Laboratories (NREL), in OLED devices and brought them into the project. This project had a

  4. Solution-Processable Transparent Conductive Hole Injection Electrode for OLED SSL

    SciTech Connect

    Pschenitzka, Florian; Mathai, Mathew; Torke, Terri

    2012-07-15

    An interconnected network of silver nanowires has been used as transparent anode in OLED devices. This layer was deposited by spin-coating and slot-die coating from an aqueous nanowire suspension. The sheet resistance of the film was 10ohms/sq with a transmission (including the glass substrate) of higher than 85%. The first phase of the project focused on the implementation of this nanowire layer with a hole-injection-layer (HIL) which has been developed at Plextronics and has been shown to provide good stability and efficiency in conventional OLED devices. We modified the HIL solution such that it coated reasonably well with suitable surface morphology so that actual devices can be manufactured. During the second phase we investigated the hole-injection and stability of hole-onlydevices. We determined that the use of the nanowire network as anode does not introduce an additional degradation mechanism since the observed device characteristics did not differ from those made with ITO anode. We then proceeded to make actual OLED devices with this nanowire / HIL stack and achieved device characteristics similar state-of-the-art OLED devices with a single junction. In order to gain traction with potential OLED manufacturers, we decided to contract Novaled to prepare large-area demonstrators for us. For these devices, we used an allevaporated stack, i.e. we did use Novaled's HIL material instead of Plextronics. We successfully fabricated demonstrators with an area of 25cm2 with a double or triple junction stack. Minor stack optimizations were necessary to achieve efficacies and lifetime equivalent with ITO devices made with the same devices stack. Due to the reduced microcavity effect, the color of the emitted light is significantly more stable with respect to the viewing angle compared to ITO devices. This fact in conjunction with the promise of lower production cost due to the elimination of the ITO sputtering process and the direct patterning of the anode layer are

  5. Correction: Theoretical study and design of multifunctional phosphorescent platinum(ii) complexes containing triarylboron moieties for efficient OLED emitters.

    PubMed

    Wu, Yong; Shan, Guo-Gang; Li, Hai-Bin; Wu, Shui-Xing; Ren, Xin-Yao; Geng, Yun; Su, Zhong-Min

    2015-02-14

    Correction for 'Theoretical study and design of multifunctional phosphorescent platinum(ii) complexes containing triarylboron moieties for efficient OLED emitters' by Yong Wu et al., Phys. Chem. Chem. Phys., 2015, DOI: .

  6. Effects of QD concentrations and thermal annealing on the performance of self-assembly QD-OLEDs.

    PubMed

    Uddin, A; Teo, C C

    2011-12-01

    We have fabricated and investigated the effect of CdSe/ZnS quantum dot (QD) concentrations on the performance of self-assembly hybrid inorganic/organic light emitting diodes (QD-OLEDs). The uniform distribution of QDs with controllable density was achieved using the conventional spin-coating method. There was a QD threshold concentration for the emission of QDs in QD-OLED. Below that threshold concentration we did not observe the QD emission from the QD-OLED. The best performance of QD-OLED was found for the QD concentration of -9 x 10(11) cm(-2). The QD electroluminescence intensity was increased about three times after the annealing of QD-OLED at 80 degrees C for about 20 minutes in nitrogen atmosphere. The QD electroluminescence peak energy was remain same before and after the annealing of QD-OLED. The maximum external quantum efficiency was around 2.1%. The effect of process parameters and the QD emission mechanism are discussed.

  7. Production and detailed characterization of biologically active olive pollen allergen Ole e 1 secreted by the yeast Pichia pastoris.

    PubMed

    Huecas, S; Villalba, M; González, E; Martínez-Ruiz, A; Rodríguez, R

    1999-04-01

    The glycoprotein Ole e 1 is a significant aeroallergen from the olive tree (Olea europaea) pollen, with great clinical relevance in the Mediterranean area. To produce a biologically active form of recombinant Ole e 1, heterologous expression in the methylotrophic yeast Pichia pastoris was carried out. A cDNA encoding Ole e 1, fused to a Saccharomyces cerevisiae alpha-mating factor prepropeptide using the pPIC9 vector, was inserted into the yeast genome under the control of the AOX1 promoter. After induction with methanol, the protein secreted into the extracellular medium was purified by ion-exchange and size-exclusion chromatography. The structure of the isolated recombinant Ole e 1 was determined by chemical and spectroscopic techniques, and its immunological properties analysed by blotting and ELISA inhibition with Ole e 1-specific monoclonal antibodies and IgE from sera of allergic patients. The allergen was produced at a yield of 60 mg per litre of culture as a homogeneous glycosylated protein of around 18.5 kDa. Recombinant Ole e 1 appears to be properly folded, as it displays spectroscopic properties (CD and fluorescence) and immunological reactivities (IgG binding to monoclonal antibodies sensitive to denaturation and IgE from sera of allergic patients) indistinguishable from those of the natural protein. This approach gives high-yield production of homogeneous and biologically active allergen, which should be useful for scientific and clinical purposes.

  8. Solution-Procesed Small-Molecule OLED Luminaire for Interior Illumination

    SciTech Connect

    Parker, Ian

    2012-02-29

    Prototype lighting panels and luminaires were fabricated using DuPont Displays solution-processed small-molecule OLED technology. These lighting panels were based on a spatially-patterned, 3-color design, similar in concept to an OLED display panel, with materials chosen to maximize device efficacy. The majority of the processing steps take place in air (rather than high vacuum). Optimization of device architecture, processing and construction was undertaken, with a final prototype design of 50 cm{sup 2} being fabricated and tested. Performance of these panels reached 35 lm/W at illuminant-A. A unique feature of this technology is the ability to color tune the emission, and color temperatures ranging from 2700 to > 6,500K were attained in the final build. Significant attention was paid to low-cost fabrication techniques.

  9. Near-to-eye displays with embedded eye-tracking by bi-directional OLED microdisplay

    NASA Astrophysics Data System (ADS)

    Vogel, Uwe; Wartenberg, Philipp; Richter, Bernd; Brenner, Stephan; Baumgarten, Judith; Thomschke, Michael; Fehse, Karsten; Hild, Olaf

    2015-09-01

    Near-to-eye (NTE) projection is the major approach to "Smart Glasses", which have gained lot of traction during the last few years. Micro-displays based on organic light-emitting diodes (OLEDs) achieve high optical performance with excellent contrast ratio and large dynamic range at low power consumption, making them suitable for such application. In state-of-the-art applications the micro-display typically acts as a purely unidirectional output device. With the integration of an additional image sensor, the functionality of the micro-display can be extended to a bidirectional optical input/output device, aiming for implementation of eye-tracking capabilities in see-through (ST-)NTE applications to achieve gaze-based human-display-interaction. This paper describes a new bi-directional OLED microdisplay featuring SVGA resolution for both image display and acquisition, and its implementation with see-through NTE optics.

  10. An inconvenient influence of iridium(III) isomer on OLED efficiency.

    PubMed

    Baranoff, Etienne; Bolink, Henk J; De Angelis, Filippo; Fantacci, Simona; Di Censo, Davide; Djellab, Karim; Grätzel, Michael; Nazeeruddin, Md Khaja

    2010-10-14

    The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact performances of vacuum processed OLEDs using heteroleptic cyclometallated iridium(III) complexes as dopant.

  11. Stacked white OLED having separate red, green and blue sub-elements

    DOEpatents

    Forrest, Stephen; Qi, Xiangfei; Slootsky, Michael

    2014-07-01

    The present invention relates to efficient organic light emitting devices (OLEDs). The devices employ three emissive sub-elements, typically emitting red, green and blue, to sufficiently cover the visible spectrum. Thus, the devices may be white-emitting OLEDs, or WOLEDs. Each sub-element comprises at least one organic layer which is an emissive layer--i.e., the layer is capable of emitting light when a voltage is applied across the stacked device. The sub-elements are vertically stacked and are separated by charge generating layers. The charge-generating layers are layers that inject charge carriers into the adjacent layer(s) but do not have a direct external connection.

  12. Exciton formation in dye doped OLEDs using electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Batagin-Neto, Augusto; Gómez, Jorge A.; Castro, Fernando A.; Nüesch, Frank; Zuppiroli, Libero; Graeff, Carlos F. O.

    2011-11-01

    Electrically Detected Magnetic Resonance (EDMR) was used to investigate the influence of dye doping molecules on spin-dependent exciton formation in Aluminum (III) 8-hydroxyquinoline (Alq3) based OLEDs with different device structures and temperature ranges. 4-(dicyanomethylene)-2-methyl-6-{2-[(4-diphenylamino-phenyl]ethyl}-4H-pyran (DCM-TPA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene) were used as dopants. A strong temperature dependence have been observed for doped OLEDs, with a decrease of two orders of magnitude in EDMR signal for temperatures above ~200 K. The signal temperature dependence were fitted supposing different spin-lattice relaxation processes. The results suggest that thermally activated vibrations of dopants molecules induce spin pair dissociation, reducing the signal.

  13. Exciton formation in dye doped OLEDs using electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Batagin-Neto, Augusto; Gómez, Jorge A.; Castro, Fernando A.; Nüesch, Frank; Zuppiroli, Libero; Graeff, Carlos F. O.

    2012-02-01

    Electrically Detected Magnetic Resonance (EDMR) was used to investigate the influence of dye doping molecules on spin-dependent exciton formation in Aluminum (III) 8-hydroxyquinoline (Alq3) based OLEDs with different device structures and temperature ranges. 4-(dicyanomethylene)-2-methyl-6-{2-[(4-diphenylamino-phenyl]ethyl}-4H-pyran (DCM-TPA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene) were used as dopants. A strong temperature dependence have been observed for doped OLEDs, with a decrease of two orders of magnitude in EDMR signal for temperatures above 200 K. The signal temperature dependence were fitted supposing different spin-lattice relaxation processes. The results suggest that thermally activated vibrations of dopants molecules induce spin pair dissociation, reducing the signal.

  14. - and Electrically-Detected Magnetic Resonance Study of Electrophosphorescent Organic Light Emitting Devices (oled's).

    NASA Astrophysics Data System (ADS)

    Li, Gang; Shinar, Joseph; Jabbour, Ghassan

    2002-03-01

    The electroluminescence- and electrically-detected magnetic resonance (ELDMR and EDMR, respectively) of 2,3,7,8,12,13,17,18-octaethylporphine Pt (PtOEP)-based electrophosphorescent OLED's is described. At room temperature the measurements yield a negative (EL-quenching) spin 1/2 resonance similar to those exhibited by fluorescence-based OLED's. This resonance was concluded to result from magnetic resonance enhancement of the formation of negative bipolarons at the organic-cathode interface, which enhances the nonradiative quenching of singlet excitons (SE's). It is therefore suspected that similar quenching of SE's by charges at the organic/cathode interface may compete significantly with the transfer of the SE energy to TE's in the electrophosphorescent devices as well.

  15. High-throughput quantum chemistry and virtual screening for OLED material components

    NASA Astrophysics Data System (ADS)

    Halls, Mathew D.; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang

    2013-09-01

    Computational structure enumeration, analysis using an automated simulation workflow and filtering of large chemical structure libraries to identify lead systems, has become a central paradigm in drug discovery research. Transferring this paradigm to challenges in materials science is now possible due to advances in the speed of computational resources and the efficiency and stability of chemical simulation packages. State-of-the-art software tools that have been developed for drug discovery can be applied to efficiently explore the chemical design space to identify solutions for problems such as organic light-emitting diode material components. In this work, virtual screening for OLED materials based on intrinsic quantum mechanical properties is illustrated. Also, a new approach to more reliably identify candidate systems is introduced that is based on the chemical reaction energetics of defect pathways for OLED materials.

  16. Benzobisoxazole cruciforms: A tunable, cross-conjugated platform for the generation of deep blue OLED materials

    SciTech Connect

    Chavez, III, Ramiro; Cai, Min; Tlach, Brian; Wheeler, David L.; Kaudal, Rajiv; Tsyrenova, Ayuna; Tomlinson, Aimee L.; Shinar, Ruth; Shinar, Joseph; Jeffries-EL, Malika

    2016-01-20

    Four new cross-conjugated small molecules based on a central benzo[1,2-d:4,5-d']bisoxazole moiety possessing semi-independently tunable HOMO and LUMO levels were synthesized and the properties of these materials were evaluated experimentally and theoretically. The molecules were thermally stable with 5% weight loss occurring well above 350 °C. The cruciforms all exhibited blue emission in solution ranging from 433–450 nm. Host–guest OLEDs fabricated from various concentrations of these materials using the small molecule host 4,4'-bis(9-carbazolyl)-biphenyl (CBP) exhibited deep blue-emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15 ≤ x ≤ 0.17, 0.05 ≤ y ≤ 0.11), and maximum luminance efficiencies as high as ~2 cd A–1. Lastly, these results demonstrate the potential of benzobisoxazole cruciforms as emitters for developing high-performance deep blue OLEDs.

  17. Spontaneous Fluctuations of Transition Dipole Moment Orientation in OLED Triplet Emitters.

    PubMed

    Steiner, Florian; Bange, Sebastian; Vogelsang, Jan; Lupton, John M

    2015-03-19

    The efficiency of an organic light-emitting diode (OLED) depends on the microscopic orientation of transition dipole moments of the molecular emitters. The most effective materials used for light generation have 3-fold symmetry, which prohibits a priori determination of dipole orientation due to the degeneracy of the fundamental transition. Single-molecule spectroscopy reveals that the model triplet emitter tris(1-phenylisoquinoline)iridium(III) (Ir(piq)3) does not behave as a linear dipole, radiating with lower polarization anisotropy than expected. Spontaneous symmetry breaking occurs in the excited state, leading to a random selection of one of the three ligands to form a charge-transfer state with the metal. This nondeterministic localization is revealed in switching of the degree of linear polarization of phosphorescence. Polarization scrambling likely raises out-coupling efficiency and should be taken into account when deriving molecular orientation of the guest emitter within the OLED host from ensemble angular emission profiles.

  18. High efficiency and stable-yellow phosphorescence from OLEDs with a novel fluorinated heteroleptic iridium complex

    NASA Astrophysics Data System (ADS)

    Lv, Yan-Li; Hu, Yong-Xu; Zhao, Jin-Hui; Zhao, Guang-Wei; Qi, Ying; Li, Xiao; Chi, Hai-Jun; Dong, Yan; Xiao, Guo-Yong; Su, Zi-Sheng

    2015-11-01

    The performance of a heteroleptic bis-cyclometalated iridium complex based on 2-(2,3,4-trifluorophenyl)benzo[d]thiazole [(tfbt)2Ir(acac)] was investigated as a new phosphorescent emitter in OLEDs. The devices showed very high efficiency at various dopant concentrations and maximum efficiency was achieved at 6 wt% dopant concentration. A comparison of the performances of phosphorescent OLEDs with the new emitter versus those with prototype-based (bt)2Ir(acac) emitter revealed a remarkable improvement of efficiency at all dopant concentrations. These preliminary results obtained with the tfbt-based emitter indicate that this family of cyclometalated ligands with multi-fluorine functionalization is a promising compound for the development of highly emissive complexes.

  19. Improving operation lifetime of OLED by using thermally activated delayed fluorescence as host

    NASA Astrophysics Data System (ADS)

    Hu, Jun-tao; Hu, Sheng; Ye, Kang-li; Wei, Qing-qing; Xu, Kai; Wang, Xiang-hua

    2017-07-01

    We fabricated organic light-emitting diodes (OLEDs) with the thermally activated delayed fluorescence (TADF) material of 4CzIPN, which show better stability compared with the 4,4'-Bis(carbazol-9-yl)biphenyl (CBP) based devices. The half lifetime of the device using 4CzIPN as host material has doubled, and a slower voltage rise compared with that of CBP-based devices has been achieved, which indicates the improvement of stability. We attribute the better stability to the good film morphology and difficult crystallization property of 4CzIPN. Our results suggest that employing the 4CzIPN as host material can be a promising way of fabricating OLEDs with longer operation lifetime.

  20. Titanium dioxide thin films deposited by plasma enhanced atomic layer deposition for OLED passivation.

    PubMed

    Kim, Woong-Sun; Ko, Myoung-Gyun; Kim, Tae-Sub; Park, Sang-Kyun; Moon, Yeon-Keon; Lee, Su-Hwan; Park, Jae-Gun; Park, Jong-Wan

    2008-09-01

    Plasma enhanced atomic layer deposition (PEALD) of titanium dioxide thin films was conducted using Tetrakis dimethylamino titanium (TDMATi) and an oxygen plasma on a polyethersulfon (PES) substrate at a deposition temperature of 90 degrees C. The effects of the induced plasma power on passivation properties were investigated according to film thickness. The growth rate of the titanium dioxide film was 0.8 A/cycle, and the water vapor transmission rate (WTVR) for a 80 nm titanium dioxide film was 0.023 g/m2 day. The passivation performance of the titanium dioxide film was investigated using an organic light-emitting diode (OLED). The coated OLED lifetime was 90 h, 15 times longer than that of an uncoated sample.

  1. Dicyanomethylene-4H-pyran chromophores for OLED emitters, logic gates and optical chemosensors.

    PubMed

    Guo, Zhiqian; Zhu, Weihong; Tian, He

    2012-06-21

    Dicyanomethylene-4H-pyran (DCM) chromophores are typical donor-π-acceptor (D-π-A) type chromophores with a broad absorption band resulting from an ultra-fast internal charge-transfer (ICT) process. In 1989, Tang et al. firstly introduced a DCM derivative as a highly fluorescent dopant in organic electroluminescent diodes (OLEDs). Integration of ICT chromophore-receptor systems based on DCM chromophores with ion-induced shifts in absorption or emission is a convenient method to perform the logic expression for molecular logic gates. In recent years, various DCM-type derivatives have been explored due to their excellent optical-electronic properties and diverse structural modification. This feature article provides an insight into how the structural modification of DCM chromophores can be utilized for OLED emitters, logic gates and optical chemosensors. In addition, the aggregation-induced-emission (AIE) of DCM derivatives for further optical applications was also introduced.

  2. Templateless electrodeposition ZnO nanowires for charge transport optimization in OLED structures

    NASA Astrophysics Data System (ADS)

    Polosan, S.; Matei, E.; Ciobotaru, I. C.; Ciobotaru, C. C.

    2016-10-01

    Passivated zinc oxide nanowires (NW) were used to improve the charge injection in organic light-emitting diode (OLED) structures. Conducting polymers, deposited on the well-dispersed ZnO NW, were used to modify the electrical conductivity across the OLED structure because the charge transport is influenced by the interface interactions. Passivation with polymers improves the transport characteristics of the device due to the interaction between ZnO NW and PEDOT:PSS polymer. The hole current density increases with the ZnO NW concentration, which made the current injection more balanced and therefore enhanced the electroluminescence efficiency. A templateless electrochemical deposition method was used to grow zinc oxide nanowires on an ITO/glass substrate because parameters such as the densities and dimensions of the nanowires can be controlled to produce thin and well dispersed structures.

  3. Iridium(III) soft salts from dinuclear cationic and mononuclear anionic complexes for OLED devices.

    PubMed

    Nasr, Gihane; Guerlin, Audrey; Dumur, Frédéric; Beouch, Layla; Dumas, Eddy; Clavier, Gilles; Miomandre, Fabien; Goubard, Fabrice; Gigmes, Didier; Bertin, Denis; Wantz, Guillaume; Mayer, Cédric R

    2011-10-14

    Two iridium(III) soft salts based on ion-paired dinuclear cationic and mononuclear anionic complexes were designed and investigated as phosphorescent emitters for solution processed OLEDs. New dinuclear cationic complexes were prepared with two different bridging ligands, a carbazole and a phenylene spacer. Best devices were designed with the soft salt bearing a carbazole moiety. This journal is © The Royal Society of Chemistry 2011

  4. NMR solution structure of Ole e 6, a major allergen from olive tree pollen.

    PubMed

    Treviño, Miguel Angel; García-Mayoral, María Flor; Barral, Patricia; Villalba, Mayte; Santoro, Jorge; Rico, Manuel; Rodríguez, Rosalía; Bruix, Marta

    2004-09-10

    Ole e 6 is a pollen protein from the olive tree (Olea europaea) that exhibits allergenic activity with a high prevalence among olive-allergic individuals. The three-dimensional structure of Ole e 6 has been determined in solution by NMR methods. This is the first experimentally determined structure of an olive tree pollen allergen. The structure of this 50-residue protein is based on 486 upper limit distance constraints derived from nuclear Overhauser effects and 24 torsion angle restraints. The global fold of Ole e 6 consists of two nearly antiparallel alpha-helices, spanning residues 3-19 and 23-33, that are connected by a short loop and followed by a long, unstructured C-terminal tail. Viewed edge-on, the structured N terminus has a dumbbell-like shape with the two helices on the outside and with the hydrophobic core, mainly composed of 3 aromatic and 6 cysteine residues, on the inside. All the aromatic rings lie on top of and pack against the three disulfide bonds. The lack of thermal unfolding, even at 85 degrees C, indicates a high conformational stability. Based on the analysis of the molecular surface, we propose five plausible epitopes for IgE recognition. The results presented here provide the structural foundation for future experiments to verify the antigenicity of the proposed epitopes, as well as to design novel hypoallergenic forms of the protein suitable for diagnosis and treatment of type-I allergies. In addition, three-dimensional structure features of Ole e 6 are discussed to provide a basis for future functional studies.

  5. Roll-To-Roll Process for Transparent Metal Electrodes in OLED Manufacturing

    SciTech Connect

    Slafer, W. Dennis

    2010-06-02

    This program will develop and demonstrate a new manufacturing technology that can help to improve the efficiency and reduce the cost of producing the next generation solid-state lighting (OLEDs)for a broad range of commercial applications. This will not only improve US competitiveness in the manufacturing sector but will also result in a positive impact in meeting the Department of Energy’s goal of developing high efficiency lighting while reducing the environmental impact.

  6. Multi-layer printing of OLEDs as a tool for the creation of security features.

    PubMed

    Fischer, Bert; Kreissl, Stefanie; Boeffel, Christine; Wedel, Armin

    2012-03-12

    The combined deposition of structured and homogenous layers for the device setup of OLEDs results in a structured display visible with a gray scale impression. These permanently imprinted structures are only visible during the application of an electrical field and almost invisible in the off state. Most intriguing applications of such devices are security marks, electronic watermarks but also for advertising and design applications the creation of gray scale structures might have interesting applications.

  7. Electrical investigations of hybrid OLED microcavity structures with novel encapsulation methods

    NASA Astrophysics Data System (ADS)

    Meister, Stefan; Brückner, Robert; Fröb, Hartmut; Leo, Karl

    2016-04-01

    An electrical driven organic solid state laser is a very challenging goal which is so far well beyond reach. As a step towards realization, we monolithically implemented an Organic Light Emitting Diode (OLED) into a dielectric, high quality microcavity (MC) consisting of two Distributed Bragg Reectors (DBR). In order to account for an optimal optical operation, the OLED structure has to be adapted. Furthermore, we aim to excite the device not only electrically but optically as well. Different OLED structures with an emission layer consisting of Alq3:DCM (2 wt%) were investigated. The External Quantum Efficiencies (EQE) of this hybrid structures are in the range of 1-2 %, as expected for this material combination. Including metal layers into a MC is complicated and has a huge impact on the device performance. Using Transfer-Matrix-Algorithm (TMA) simulations, the best positions for the metal electrodes are determined. First, the electroluminescence (EL) of the adjusted OLED structure on top of a DBR is measured under nitrogen atmosphere. The modes showed quality factors of Q = 60. After the deposition of the top DBR, the EL is measured again and the quality factors increased up to Q = 600. Considering the two 25-nm-thick-silver contacts a Q-factor of 600 is very high. The realization of a suitable encapsulation method is important. Two approaches were successfully tested. The first method is based on the substitution of a DBR layer with a layer produced via Atomic Layer Deposition (ALD). The second method uses a 0.15-mm-thick cover glass glued on top of the DBR with a 0.23-μm-thick single-component glue layer. Due to the working encapsulation, it is possible to investigate the sample under ambient conditions.

  8. Fabrication of a three-dimensional nanoporous polymer film as a diffuser for microcavity OLEDs

    NASA Astrophysics Data System (ADS)

    Pyo, Beom; Cho, Ye Ram; Suh, Min Chul

    2015-09-01

    We used a nanoporous polymer film prepared by cellulose acetate butyrate with ~40% of optical haze value as a diffuser. It was fabricated by a simple spin-coating process during continuous water mist supply by a humidifier. The pores were created by the elastic bouncing mechanism (rather than the thermocapillary convection mechanism) of the supplied water droplets. The shapes and sizes of the caves formed near the polymer surface are randomly distributed, with a relatively narrow pore size distribution (300-500 nm). Specifically, we focused on controlling the surface morphology to give a three-dimensional (3D) multi-stacked nanocave structure because we had already learnt that two-dimensional nanoporous structures showed serious loss of luminance in the forward direction. Using this approach, we found that the 3D nanoporous polymer film can effectively reduce the viewing angle dependency of strong microcavity OLEDs without any considerable decrease in the total intensity of the out-coupled light. We applied this nanoporous polymer film to microcavity OLEDs to investigate the possibility of using it as a diffuser layer. The resulting nanoporous polymer film effectively reduced the viewing angle dependency of the microcavity OLEDs, although a pixel blurring phenomenon occurred. Despite its negative effects, such as the drop in efficiency in the forward direction and the pixel blurring, the introduction of a nanoporous polymer film as a scattering medium on the back side of the glass substrate eliminated the viewing angle dependency. Thus, this approach is a promising method to overcome the serious drawbacks of microcavity OLEDs.

  9. Organic/Organic Heterointerface Engineering to Boost Carrier Injection in OLEDs

    PubMed Central

    Fathollahi, Mohammadreza; Ameri, Mohsen; Mohajerani, Ezeddin; Mehrparvar, Ebrahim; Babaei, Mohammadrasoul

    2017-01-01

    We investigate dynamic formation of nanosheet charge accumulations by heterointerface engineering in double injection layer (DIL) based organic light emitting diodes (OLEDs). Our experimental results show that the device performance is considerably improved for the DIL device as the result of heterointerface injection layer (HIIL) formation, in comparison to reference devices, namely, the current density is doubled and even quadrupled and the turn-on voltage is favorably halved, to 3.7 V, which is promising for simple small-molecule OLEDs. The simulation reveals the (i) formation of dynamic p-type doping (DPD) region which treats the quasi Fermi level at the organic/electrode interface, and (ii) formation of dynamic dipole layer (DDL) and the associated electric field at the organic/organic interface which accelerates the ejection of the carriers and their transference to the successive layer. HIIL formation proposes alternate scenarios for device design. For instance, no prerequisite for plasma treatment of transparent anode electrode, our freedom in varying the thicknesses of the organic layers between 10 nm and 60 nm for the first layer and between 6 nm and 24 nm for the second layer. The implications of the present work give insight into the dynamic phenomena in OLEDs and facilitates the development of their inexpensive fabrication for lighting applications. PMID:28218246

  10. Multiview three-dimensional display with continuous motion parallax through planar aligned OLED microdisplays.

    PubMed

    Teng, Dongdong; Xiong, Yi; Liu, Lilin; Wang, Biao

    2015-03-09

    Existing multiview three-dimensional (3D) display technologies encounter discontinuous motion parallax problem, due to a limited number of stereo-images which are presented to corresponding sub-viewing zones (SVZs). This paper proposes a novel multiview 3D display system to obtain continuous motion parallax by using a group of planar aligned OLED microdisplays. Through blocking partial light-rays by baffles inserted between adjacent OLED microdisplays, transitional stereo-image assembled by two spatially complementary segments from adjacent stereo-images is presented to a complementary fusing zone (CFZ) which locates between two adjacent SVZs. For a moving observation point, the spatial ratio of the two complementary segments evolves gradually, resulting in continuously changing transitional stereo-images and thus overcoming the problem of discontinuous motion parallax. The proposed display system employs projection-type architecture, taking the merit of full display resolution, but at the same time having a thin optical structure, offering great potentials for portable or mobile 3D display applications. Experimentally, a prototype display system is demonstrated by 9 OLED microdisplays.

  11. Generation of 360° three-dimensional display using circular-aligned OLED microdisplays.

    PubMed

    Teng, Dongdong; Liu, Lilin; Wang, Biao

    2015-02-09

    A 360° all-around multiview three-dimensional (3D) display system is proposed by using coarse-pitch circular-aligned OLED microdisplays. The magnified virtual color images projected from microdisplays serve as stereo images, which can create separate eyeboxes for the viewer. Through inserting baffles, a transitional stereo image assembled by two spatially complementary segments from adjacent stereo images is presented to a complementary fusing zone (CFZ) which locates between adjacent eyeboxes. For a moving observation point, the spatial ratio of the two complementary segments evolves gradually, resulting in continuously changing transitional stereo images and thus overcoming the problem of discontinuous moving parallax. Such a controllable light-ray fusing technology, assured by the inherent large divergent angle of OLED pixels, decreases the required number of display panels for 360° multiview 3D display greatly. A prototype display system with only 67 full-color OLED microdisplays is set up to demonstrate the 360° 3D color display. The develop system is freed from the dependence on mechanical moving elements, high-speed components and diffusion screens.

  12. On the origin of exciton formation in dye doped Alq3 OLEDs

    NASA Astrophysics Data System (ADS)

    Gómez, J. A.; Castro, F. A.; Nüesch, F.; Zuppiroli, L.; Graeff, C. F. O.

    2012-09-01

    Electrically Detected Magnetic Resonance (EDMR) was used to investigate the influence of dye doping on spin-dependent exciton formation in aluminum (III) 8-hydroxyquinoline (Alq3) based Organic Light Emitting Diodes (OLEDs) with different device structures. 4-(dicyanomethylene)-2-methyl-6-{2-[(4-diphenylamino)-phenyl]ethyl}-4H-pyran (DCM-TPA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene) were used as dopants. Results at room temperature show significant differences on the EDMR spectra (g-factor and linewidth) of doped and undoped devices. Signals from DCM-TPA and Rubrene dye doped OLEDs showed strong temperature dependence, with signal intensity increasing by 2 orders of magnitude below 200 K for DCM-TPA dye doped OLEDs and increasing by ˜1 order of magnitude below 225 K for the Rubrene dye doped device, while undoped devices shows almost no temperature dependence. By adding a "spacer" layer of undoped Alq3 at the recombination zone, changes in bias voltage were used to shift the recombination from doped to undoped region and correlate that with changes in the EDMR spectrum. Our results are indicating that charge trapping on the dopant followed by recombination is the main mechanism of light emission in the investigated devices.

  13. Investigation on a short circuit of large-area OLED lighting panels

    NASA Astrophysics Data System (ADS)

    Park, J. W.; Kim, T. W.; Park, J. B.

    2013-04-01

    A short circuit often arises from large-area organic light-emitting device (OLED) lighting panels due to particles (i.e. dust, organic or metal debris) or the spike-like surface of the indium-tin-oxide (ITO) anode. On the emergence of a short circuit, an instant current crowding occurs, thereby reducing substantially the resistance of the panels and causing a failure of a dimming control. In this paper, we investigate the effect of the surface morphology of ITO on the resistance and dimmability of the panels. We have demonstrated that the peak-to-valley roughness of ITO should be much less than 20 nm or the resistance of the panels should be much higher than 1 MΩ in order to avoid an unwanted short-circuit phenomenon and thus achieve the high-yield fabrication of OLED lighting panels. It is also addressed that much care is taken to ensure a dimming control of OLED lighting panels with a larger active area because the resistance of those panels varies depending more sensitively on the surface roughness of ITO.

  14. Candle light-style OLED: a plausibly human-friendly safe night light

    NASA Astrophysics Data System (ADS)

    Jou, Jwo-Huei; Chen, Po-Wei; Hsieh, Chun-Yu; Wang, Ching-Chiun; Chen, Chien-Chih; Tung, F.-C.; Chen, Szu-Hao; Wang, Yi-Shan

    2013-09-01

    Candles emit sensationally-warm light with a very-low color-temperature, comparatively most suitable for use at night. In response to the need for such a human-friendly night light, we demonstrate the employment of a high number of candle light complementary organic emitters to generate mimic candle light based on organic light emitting diode (OLED). One resultant candle light-style OLED shows a very-high color rendering index, with an efficacy at least 300 times that of candles or twice that of an incandescent bulb. The device can be fabricated, for example, by using four candle light complementary emitters, namely: red, yellow, green, and sky-blue phosphorescent dyes, vacuum-deposited into two emission layers, separated by a nano-layer of carrier modulation material to maximize both the desirable very-high color rendering index and energy efficiency, while keeping the blue emission very low and red emission high to obtain the desirable low color temperature. With different layer structures, the OLEDs can also show color tunable between that of candle light and dusk-hue. Importantly, a romantic sensation giving and supposedly physiologically-friendly candle light-style emission can hence be driven by electricity in lieu of the hydrocarbon-burning and greenhouse gas releasing candles that were invented 5,000 years ago.

  15. Ole e 3, an olive-tree allergen, belongs to a widespread family of pollen proteins.

    PubMed

    Batanero, E; Villalba, M; Ledesma, A; Puente, X S; Rodríguez, R

    1996-11-01

    An allergen has been isolated from a saline extract of olive tree (Olea europaea) pollen. The protein consists of a single polypeptide chain of 9.2-kDa, as determined by mass spectrometry. It contains neither tryptophan nor tyrosine residues, and displays an acidic isoelectric point. The secondary structure of the protein, estimated from the analysis of the circular-dichroism spectrum in the peptide-bond region, is composed of 52% alpha-helix, 10% beta-strand, 29% beta-turn and 9% non-regular conformation. The N-terminal end of the protein is blocked. Amino-acid-sequence data have been obtained from peptides produced by CNBr treatment of the native allergen. A partial sequence of 36 amino acids has thus been elucidated. The protein exhibits sequence similarity with pollen allergens from Brassica species and contains a Ca(2+)-binding motif. The isolated protein displays IgE-binding activity against sera of patients allergic to olive-tree pollen. It has been named Ole e 3, according to the recommendations of the IUIS Nomenclature Committee. IgG ELISA inhibition assays with polyclonal antibodies specific for Ole e 3 reveal the presence of proteins similar to Ole e 3 in the pollen from non-related plant species, which may explain allergic cross-reactivity processes.

  16. Organic/Organic Heterointerface Engineering to Boost Carrier Injection in OLEDs

    NASA Astrophysics Data System (ADS)

    Fathollahi, Mohammadreza; Ameri, Mohsen; Mohajerani, Ezeddin; Mehrparvar, Ebrahim; Babaei, Mohammadrasoul

    2017-02-01

    We investigate dynamic formation of nanosheet charge accumulations by heterointerface engineering in double injection layer (DIL) based organic light emitting diodes (OLEDs). Our experimental results show that the device performance is considerably improved for the DIL device as the result of heterointerface injection layer (HIIL) formation, in comparison to reference devices, namely, the current density is doubled and even quadrupled and the turn-on voltage is favorably halved, to 3.7 V, which is promising for simple small-molecule OLEDs. The simulation reveals the (i) formation of dynamic p-type doping (DPD) region which treats the quasi Fermi level at the organic/electrode interface, and (ii) formation of dynamic dipole layer (DDL) and the associated electric field at the organic/organic interface which accelerates the ejection of the carriers and their transference to the successive layer. HIIL formation proposes alternate scenarios for device design. For instance, no prerequisite for plasma treatment of transparent anode electrode, our freedom in varying the thicknesses of the organic layers between 10 nm and 60 nm for the first layer and between 6 nm and 24 nm for the second layer. The implications of the present work give insight into the dynamic phenomena in OLEDs and facilitates the development of their inexpensive fabrication for lighting applications.

  17. Cost-Effective Force Field Tailored for Solid-Phase Simulations of OLED Materials.

    PubMed

    Moral, M; Son, W-J; Sancho-García, J C; Olivier, Y; Muccioli, L

    2015-07-14

    A united atom force field is empirically derived by minimizing the difference between experimental and simulated crystal cells and melting temperatures for eight compounds representative of organic electronic materials used in OLEDs and other devices: biphenyl, carbazole, fluorene, 9,9'-(1,3-phenylene)bis(9H-carbazole)-1,3-bis(N-carbazolyl)benzene (mCP), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (pCBP), phenazine, phenylcarbazole, and triphenylamine. The force field is verified against dispersion-corrected DFT calculations and shown to also successfully reproduce the crystal structure for two larger compounds employed as hosts in phosphorescent and thermally activated delayed fluorescence OLEDs: N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD), and 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBI). The good performances of the force field coupled to the large computational savings granted by the united atom approximation make it an ideal choice for the simulation of the morphology of emissive layers for OLED materials in crystalline or glassy phases.

  18. Improvement of OLED properties with the AlN insulated layer

    NASA Astrophysics Data System (ADS)

    Liu, Chunling; Wang, Jin; Wang, Chunwu; Zhao, Lei; Jiang, Wenlong

    2010-11-01

    The thin aluminum nitride(AlN) film using as an insulating layer was inserted between the anode (ITO) and the NPB organic film in the organic light-emitting devices(OLED) for the structure being K9/ITO/AlN/NPB/Alq3/LiF/Al.The effect of the different thickness AlN film on the device performance was investigated. After optimization, improvement of OLEDs properties is biggest when the AlN film thickness is about 0.4nm.Such a structure with AlN layer facilitates the increase of current density and decrease of threshold voltage, resulting in an improved luminance and energy efficiency. The average luminance increased by about 30% and an improvement of 21.8% on the average current density. The lifetime experiment of the devices has proved an improvement on stability because of inserted AlN film. This phenomenon is mainly because of the insulating capability of the aluminum nitride coating and the passivation role of AlN film to the ITO surface. The processing is simple and high efficient, can be widely applied to the OLED devices.

  19. Integration of OLEDs in biomedical sensor systems: design and feasibility analysis

    NASA Astrophysics Data System (ADS)

    Rai, Pratyush; Kumar, Prashanth S.; Varadan, Vijay K.

    2010-04-01

    Organic (electronic) Light Emitting Diodes (OLEDs) have been shown to have applications in the field of lighting and flexible display. These devices can also be incorporated in sensors as light source for imaging/fluorescence sensing for miniaturized systems for biomedical applications and low-cost displays for sensor output. The current device capability aligns well with the aforementioned applications as low power diffuse lighting and momentary/push button dynamic display. A top emission OLED design has been proposed that can be incorporated with the sensor and peripheral electrical circuitry, also based on organic electronics. Feasibility analysis is carried out for an integrated optical imaging/sensor system, based on luminosity and spectrum band width. A similar study is also carried out for sensor output display system that functions as a pseudo active OLED matrix. A power model is presented for device power requirements and constraints. The feasibility analysis is also supplemented with the discussion about implementation of ink-jet printing and stamping techniques for possibility of roll to roll manufacturing.

  20. Hydrogen peroxide-independent production of α-alkenes by OleTJE P450 fatty acid decarboxylase

    PubMed Central

    2014-01-01

    Background Cytochrome P450 OleTJE from Jeotgalicoccus sp. ATCC 8456, a new member of the CYP152 peroxygenase family, was recently found to catalyze the unusual decarboxylation of long-chain fatty acids to form α-alkenes using H2O2 as the sole electron and oxygen donor. Because aliphatic α-alkenes are important chemicals that can be used as biofuels to replace fossil fuels, or for making lubricants, polymers and detergents, studies on OleTJE fatty acid decarboxylase are significant and may lead to commercial production of biogenic α-alkenes in the future, which are renewable and more environmentally friendly than petroleum-derived equivalents. Results We report the H2O2-independent activity of OleTJE for the first time. In the presence of NADPH and O2, this P450 enzyme efficiently decarboxylates long-chain fatty acids (C12 to C20) in vitro when partnering with either the fused P450 reductase domain RhFRED from Rhodococcus sp. or the separate flavodoxin/flavodoxin reductase from Escherichia coli. In vivo, expression of OleTJE or OleTJE-RhFRED in different E. coli strains overproducing free fatty acids resulted in production of variant levels of multiple α-alkenes, with a highest total hydrocarbon titer of 97.6 mg·l-1. Conclusions The discovery of the H2O2-independent activity of OleTJE not only raises a number of fundamental questions on the monooxygenase-like mechanism of this peroxygenase, but also will direct the future metabolic engineering work toward improvement of O2/redox partner(s)/NADPH for overproduction of α-alkenes by OleTJE. PMID:24565055

  1. High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

    PubMed Central

    Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

    2017-01-01

    An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs. PMID:28211516

  2. High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

    2017-02-01

    An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs.

  3. Device reflectivity as a simple rule for predicting the suitability of scattering foils for improved OLED light extraction

    NASA Astrophysics Data System (ADS)

    Levell, Jack W.; Harkema, Stephan; Pendyala, Raghu K.; Rensing, Peter A.; Senes, Alessia; Bollen, Dirk; MacKerron, Duncan; Wilson, Joanne S.

    2013-09-01

    A general challenge in Organic Light Emitting Diodes (OLEDs) is to extract the light efficiently from waveguided modes within the device structure. This can be accomplished by applying an additional scattering layer to the substrate which results in outcoupling increases between 0% to <100% in external quantum efficiency. In this work, we aim to address this large variation and show that the reflectivity of the OLED is a simple and useful predictor of the efficiency of substrate scattering techniques without the need for detailed modeling. We show that by optimizing the cathode and anode structure of glass based OLEDs by using silver and an ITO free high conductive Agfa Orgacon™ PEDOT:PSS we are able to increase the external quantum efficiency of OLEDs with the same outcoupling substrates from 2.4% to 5.6%, an increase of 130%. In addition, Holst Centre and partners are developing flexible substrates with integrated light extraction features and roll to roll compatible processing techniques to enable this next step in OLED development both for lighting and display applications. These devices show promise as they are shatterproof substrates and facilitate low cost manufacture.

  4. High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling.

    PubMed

    Kim, Hyo-Jun; Shin, Min-Ho; Kim, Joo-Suc; Kim, Se-Eun; Kim, Young-Joo

    2017-02-17

    An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20 wt% concentration. This enhancement comes from the two facts that the QD patterns downconvert unnecessary blue or blue/green light to the required green or red light and the air-gapped bridges increase the color conversion efficiency of QDs by optical recycling using total internal reflection (TIR) at the interface. In addition, the color gamut of the proposed OLED display increases from 65.5 to 75.9% (NTSC x, y ratio) due to the narrow emission spectra of QDs.

  5. Experimental test and life estimation of the OLED at normal working stress based on the luminance degradation model.

    PubMed

    Zhang, J P; Wang, C; Chen, X; Cheng, G L; Qiu, Y J; Shen, M-H H

    2015-06-01

    In order to accurately acquire the life time information for the organic light emitting diode (OLED), an experiment based on the normal stress life test was carried out to gain the data for the luminance degradation tests. The luminance degradation model of OLED was established based on the Weibull function and the least square method. Combined with luminance degradation data, Weibull parameters were estimated, the qualitative and the quantitative relationship between the initial luminance and the OLED life was obtained, and the life estimation of the product was achieved. Numerical results show that the test scheme is feasible, the luminance degradation model proves to be reliable for the OLED life estimation, and the fitting accuracy is very high by comparison with the test data fluctuation. Moreover, the real life time of the OLED is measured, which can verify the validity of the assumptions used in accelerated life test methods and provide manufacturers and customers with significant guidelines. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Influence of bilayer resist processing on p-i-n OLEDs: towards multicolor photolithographic structuring of organic displays

    NASA Astrophysics Data System (ADS)

    Krotkus, Simonas; Nehm, Frederik; Janneck, Robby; Kalkura, Shrujan; Zakhidov, Alex A.; Schober, Matthias; Hild, Olaf R.; Kasemann, Daniel; Hofmann, Simone; Leo, Karl; Reineke, Sebastian

    2015-03-01

    Recently, bilayer resist processing combined with development in hydrofluoroether (HFE) solvents has been shown to enable single color structuring of vacuum-deposited state-of-the-art organic light-emitting diodes (OLED). In this work, we focus on further steps required to achieve multicolor structuring of p-i-n OLEDs using a bilayer resist approach. We show that the green phosphorescent OLED stack is undamaged after lift-off in HFEs, which is a necessary step in order to achieve RGB pixel array structured by means of photolithography. Furthermore, we investigate the influence of both, double resist processing on red OLEDs and exposure of the devices to ambient conditions, on the basis of the electrical, optical and lifetime parameters of the devices. Additionally, water vapor transmission rates of single and bilayer system are evaluated with thin Ca film conductance test. We conclude that diffusion of propylene glycol methyl ether acetate (PGMEA) through the fluoropolymer film is the main mechanism behind OLED degradation observed after bilayer processing.

  7. Novel Low Cost Organic Vapor Jet Printing of Striped High Efficiency Phosphorescent OLEDs for White Lighting

    SciTech Connect

    Mike Hack

    2008-12-31

    In this program, Universal Display Corporation and University of Michigan proposed to integrate three innovative concepts to meet the DOE's Solid State Lighting (SSL) goals: (1) high-efficiency phosphorescent organic light emitting device (PHOLED{trademark}) technology, (2) a white lighting design that is based on a series of red, green and blue OLED stripes, and (3) the use of a novel cost-effective, high rate, mask-less deposition process called organic vapor jet printing (OVJP). Our PHOLED technology offers up to four-times higher power efficiency than other OLED approaches for general lighting. We believe that one of the most promising approaches to maximizing the efficiency of OLED lighting sources is to produce stripes of the three primary colors at such a pitch (200-500 {mu}m) that they appear as a uniform white light to an observer greater than 1 meter (m) away from the illumination source. Earlier work from a SBIR Phase 1 entitled 'White Illumination Sources Using Striped Phosphorescent OLEDs' suggests that stripe widths of less than 500 {mu}m appear uniform from a distance of 1m without the need for an external diffuser. In this program, we intend to combine continued advances in this PHOLED technology with the striped RGB lighting design to demonstrate a high-efficiency, white lighting source. Using this background technology, the team has focused on developing and demonstrating the novel cost-effective OVJP process to fabricate these high-efficiency white PHOLED light sources. Because this groundbreaking OVJP process is a direct printing approach that enables the OLED stripes to be printed without a shadow mask, OVJP offers very high material utilization and high throughput without the costs and wastage associated with a shadow mask (i.e. the waste of material that deposits on the shadow mask itself). As a direct printing technique, OVJP also has the potential to offer ultra-high deposition rates (> 1,000 Angstroms/second) for any size or shaped

  8. Blue fluorescent OLED materials and their application for high-performance devices

    NASA Astrophysics Data System (ADS)

    Kuma, Hitoshi; Hosokawa, Chishio

    2014-06-01

    The authors applied two technologies to improve the efficiency of fluorescent blue organic light-emitting diodes (OLEDs). First, an efficiency-enhancement layer (EEL) was introduced to boost triplet-triplet fusion (TTF). Second, new blue dopants with a higher orientation factor in the emitting layer were developed. Consequently, the external quantum efficiency (EQE) was increased up to 11.5% with Commission Internationale de l’Eclairage (CIE) 1931 color coordinates of (0.138, 0.092). The reported results may lead to EQEs that exceed 14% with fluorescent blue emitters.

  9. Balance the Carrier Mobility To Achieve High Performance Exciplex OLED Using a Triazine-Based Acceptor.

    PubMed

    Hung, Wen-Yi; Chiang, Pin-Yi; Lin, Shih-Wei; Tang, Wei-Chieh; Chen, Yi-Ting; Liu, Shih-Hung; Chou, Pi-Tai; Hung, Yi-Tzu; Wong, Ken-Tsung

    2016-02-01

    A star-shaped 1,3,5-triazine/cyano hybrid molecule CN-T2T was designed and synthesized as a new electron acceptor for efficient exciplex-based OLED emitter by mixing with a suitable electron donor (Tris-PCz). The CN-T2T/Tris-PCz exciplex emission shows a high ΦPL of 0.53 and a small ΔET-S = -0.59 kcal/mol, affording intrinsically efficient fluorescence and highly efficient exciton up-conversion. The large energy level offsets between Tris-PCz and CN-T2T and the balanced hole and electron mobility of Tris-PCz and CN-T2T, respectively, ensuring sufficient carrier density accumulated in the interface for efficient generation of exciplex excitons. Employing a facile device structure composed as ITO/4% ReO3:Tris-PCz (60 nm)/Tris-PCz (15 nm)/Tris-PCz:CN-T2T(1:1) (25 nm)/CN-T2T (50 nm)/Liq (0.5 nm)/Al (100 nm), in which the electron-hole capture is efficient without additional carrier injection barrier from donor (or acceptor) molecule and carriers mobilities are balanced in the emitting layer, leads to a highly efficient green exciplex OLED with external quantum efficiency (EQE) of 11.9%. The obtained EQE is 18% higher than that of a comparison device using an exciplex exhibiting a comparable ΦPL (0.50), in which TCTA shows similar energy levels but higher hole mobility as compared with Tris-PCz. Our results clearly indicate the significance of mobility balance in governing the efficiency of exciplex-based OLED. Exploiting the Tris-PCz:CN-T2T exciplex as the host, we further demonstrated highly efficient yellow and red fluorescent OLEDs by doping 1 wt % Rubrene and DCJTB as emitter, achieving high EQE of 6.9 and 9.7%, respectively.

  10. Synthesis, Characterization, Physical Properties, and OLED Application of Single BN-Fused Perylene Diimide.

    PubMed

    Li, Gang; Zhao, Yongbiao; Li, Junbo; Cao, Jun; Zhu, Jia; Sun, Xiao Wei; Zhang, Qichun

    2015-01-02

    It is very challenging to introduce azaborine into an electron-deficient arene system because of unfavorable intramolecular electrophilic borylation reaction. In this report, we adopted a straightforward methodology to construct a large BN-embedded π-system based on perylene diimide (PDI), which is the first BN-annulation example with highly electron-withdrawing polycyclic aromatic hydrocarbons. The physical properties of the as-prepared N,N-dicyclohexyl-1-aza-12-bora-benzoperylene diimide (PDI-1BN) have been fully studied, and its sensing behavior to fluoride ion as well as its OLED performance was also investigated.

  11. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics

    NASA Astrophysics Data System (ADS)

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-06-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported.

  12. Luminous butterflies: efficient exciton harvesting by benzophenone derivatives for full-color delayed fluorescence OLEDs.

    PubMed

    Lee, Sae Youn; Yasuda, Takuma; Yang, Yu Seok; Zhang, Qisheng; Adachi, Chihaya

    2014-06-16

    Butterfly-shaped luminescent benzophenone derivatives with small energy gaps between their singlet and triplet excited states are used to achieve efficient full-color delayed fluorescence. Organic light-emitting diodes (OLEDs) with these benzophenone derivatives doped in the emissive layer can generate electroluminescence ranging from blue to orange-red and white, with maximum external quantum efficiencies of up to 14.3%. Triplet excitons are efficiently harvested through delayed fluorescence channels. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. RCWA and FDTD modeling of light emission from internally structured OLEDs.

    PubMed

    Callens, Michiel Koen; Marsman, Herman; Penninck, Lieven; Peeters, Patrick; de Groot, Harry; ter Meulen, Jan Matthijs; Neyts, Kristiaan

    2014-05-05

    We report on the fabrication and simulation of a green OLED with an Internal Light Extraction (ILE) layer. The optical behavior of these devices is simulated using both Rigorous Coupled Wave Analysis (RCWA) and Finite Difference Time-Domain (FDTD) methods. Results obtained using these two different techniques show excellent agreement and predict the experimental results with good precision. By verifying the validity of both simulation methods on the internal light extraction structure we pave the way to optimization of ILE layers using either of these methods.

  14. Photo- and electroluminescence from semiconductor colloidal quantum dots in organic matrices: QD-OLED

    SciTech Connect

    Vitukhnovskii, A. G. Vaschenko, A. A.; Bychkovskii, D. N.; Dirin, D. N.; Tananaev, P. N.; Vakshtein, M. S.; Korzhonov, D. A.

    2013-12-15

    The results are reported of an experimental study of samples of organic light-emitting diodes (OLEDs) with luminescent layers fabricated on the basis of two types of CdSe/CdS/ZnS semiconductor quantum dots (QDs) with average CdSe core diameters of 3.2 and 4.1 nm and the same overall diameters of 6.5 nm. The dependences of the LED efficiency on the applied voltage are determined. Assumptions are made about ways of optimizing the design of high-efficiency LEDs.

  15. Theoretical studies on the photophysical properties of some Iridium (III) complexes used for OLED

    NASA Astrophysics Data System (ADS)

    Urinda, Sharmistha; Das, Goutam; Pramanik, Anup; Sarkar, Pranab

    2016-09-01

    The structural and photophysical properties of four heteroleptic Iridium (III) complexes, based on 1-phenylpyrazole ligand, have been investigated theoretically. The effect of chemical substitution on the absorption and the emission spectra of the complexes has been studied and compared with the experimental data. We observe a significant structural change in the lowest triplet excited state as compared to the ground singlet state. We compute the emission wavelength of the complexes by considering the spin-orbit coupling. Using these understandings, we predict two new complexes having deeper blue emission which are supposed to be better efficient OLED materials.

  16. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics

    PubMed Central

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-01-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported. PMID:27877671

  17. Blue fluorescent OLED materials and their application for high-performance devices.

    PubMed

    Kuma, Hitoshi; Hosokawa, Chishio

    2014-06-01

    The authors applied two technologies to improve the efficiency of fluorescent blue organic light-emitting diodes (OLEDs). First, an efficiency-enhancement layer (EEL) was introduced to boost triplet-triplet fusion (TTF). Second, new blue dopants with a higher orientation factor in the emitting layer were developed. Consequently, the external quantum efficiency (EQE) was increased up to 11.5% with Commission Internationale de l'Eclairage (CIE) 1931 color coordinates of (0.138, 0.092). The reported results may lead to EQEs that exceed 14% with fluorescent blue emitters.

  18. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics.

    PubMed

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-06-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported.

  19. LABONFOIL: investigations regarding microfluidic skin patches for drug detection using flexible OLEDs

    NASA Astrophysics Data System (ADS)

    Scholles, M.; Kroker, L.; Vogel, U.; Krüger, J.; Walczak, R.; Ruano-Lopez, J.

    2010-02-01

    This contribution describes first results concerning the overall and especially optical system design of microfluidic skin patches for drug detection based on fluorescence analysis of sweat samples. This work has been carried out within the European project LABONFOIL which aims to develop low-cost lab-on-chip systems for four different applications, one of them for the detection of cocaine abuse by professional drivers. To date work has focused on the integrated design of the skin patch itself including methods for sweat collection as well as studies concerning the feasibility of OLEDs for optical excitation of the fluorescence signal.

  20. Room-temperature coupling between electrical current and nuclear spins in OLEDs

    NASA Astrophysics Data System (ADS)

    Malissa, H.; Kavand, M.; Waters, D. P.; van Schooten, K. J.; Burn, P. L.; Vardeny, Z. V.; Saam, B.; Lupton, J. M.; Boehme, C.

    2014-09-01

    The effects of external magnetic fields on the electrical conductivity of organic semiconductors have been attributed to hyperfine coupling of the spins of the charge carriers and hydrogen nuclei. We studied this coupling directly by implementation of pulsed electrically detected nuclear magnetic resonance spectroscopy in organic light-emitting diodes (OLEDs). The data revealed a fingerprint of the isotope (protium or deuterium) involved in the coherent spin precession observed in spin-echo envelope modulation. Furthermore, resonant control of the electric current by nuclear spin orientation was achieved with radiofrequency pulses in a double-resonance scheme, implying current control on energy scales one-millionth the magnitude of the thermal energy.

  1. Ash pollen allergy: reliable detection of sensitization on the basis of IgE to Ole e 1.

    PubMed

    Imhof, Konrad; Probst, Elisabeth; Seifert, Burkhardt; Regenass, Stephan; Schmid-Grendelmeier, Peter

    Background: Alongside hazel, alder and birch pollen allergies, ash pollen allergy is a relevant cause of hay fever during spring in the European region. For some considerable time, ash pollen allergy was not routinely investigated and its clinical relevance may well have been underestimated, particularly since ash and birch tree pollination times are largely the same. Ash pollen extracts are not yet well standardized and diagnosis is therefore sometimes unreliable. Olive pollen, on the other hand, is strongly cross-reactive with ash pollen and is apparently better standardized. Therefore, the main allergen of olive pollen, Ole e 1, has been postulated as a reliable alternative for the detection of ash pollen sensitization. Methods: To determine to what extent specific IgE against Ole e 1 in patients with ash pollen allergy is relevant, we included 183 subjects with ash pollen allergy displaying typical symptoms in March/April and positive skin prick test specific IgE against Ole e 1 (t224) and ash pollen (t25) and various birch allergens (Bet v 1, Bet v 2/v 4) in a retrospective study. Results: A significant correlation was seen between specific IgE against Ole e 1 and ash pollen, but also to a slightly lesser extent between IgE against Ole e 1 and skin prick test with ash pollen, the latter being even higher than IgE and skin prick test both with ash pollen. No relevant correlation was found with birch pollen allergens, demonstrating the very limited cross-reactivity between ash and birch pollen. Conclusion: It appears appropriate to determine specific IgE against Ole e 1 instead of IgE against ash pollen to detect persons with ash pollen allergy. Our findings may also support the idea of using possibly better standardized or more widely available olive pollen extracts instead of ash pollen extract for allergen-specific immunotherapy.

  2. Cloning and expression of Ole e I, the major allergen from olive tree pollen. Polymorphism analysis and tissue specificity.

    PubMed

    Villalba, M; Batanero, E; Monsalve, R I; González de la Peña, M A; Lahoz, C; Rodríguez, R

    1994-05-27

    Ole e I, the major allergen from the olive tree (Olea europaea), is one of the main causes of allergy in Mediterranean countries and some areas of North America. The cloning and sequencing of several cDNAs coding for the olive allergen have been achieved. cDNA has been synthesized from total pollen RNA and amplified by using the polymerase chain reaction. The nucleotide sequence data demonstrate the existence of microheterogeneities in at least 37 positions out of the 145 amino acids of Ole e I, thus explaining the high degree of polymorphism exhibited by the natural protein. One of the sequenced cDNAs encoding a full-length isoform was inserted into the plasmid vector pGEX-2T and overexpressed. The recombinant Ole e I has been produced in Escherichia coli as a fusion protein with glutathione S-transferase of Schistosoma japonicum. This chimeric protein was purified by affinity chromatography on a glutathione-Sepharose 4B column and digested with thrombin to release the recombinant allergen. Both the fusion protein and the recombinant Ole e I were recognized in Western blot analysis by rabbit polyclonal and mouse monoclonal antisera raised against native Ole e I as well as by the IgE of olive pollen-sensitive human sera. This indicates that the recombinant production of individual isoforms may be useful for the improvement of reagents to be used in diagnosis and therapy of IgE-mediated disorders. In addition, Ole e I mRNA has been observed to be pollen-specific as shown in a Northern blot analysis.

  3. Thermally evaporated SiO thin films as a versatile interlayer for plasma-based OLED passivation.

    PubMed

    Yun, Won Min; Jang, Jaeyoung; Nam, Sooji; Kim, Lae Ho; Seo, Sang Joon; Park, Chan Eon

    2012-06-27

    Silicon monoxide (SiO) thin films were introduced as an efficient interlayer for achieving plasma-based organic light-emitting diode (OLED) surface passivation. The SiO thin films could be consecutively formed via thermal evaporation, without breaking the vacuum, after deposition of the OLED cathode. The plasma resistivity and UV-blocking characteristics of the SiO interlayer protected the OLED devices against electrical and optical degradation during the plasma-enhanced atomic layer deposition (PEALD) and plasma-enhanced chemical vapor deposition (PECVD) passivation processes. In addition, the nonconformal deposition and hydroxyl group-rich surface characteristics of the SiO thin films yielded enhanced surface pinhole coverage and a higher initial film density in the subsequently deposited PEALD-based Al2O3 barrier film. As a result, the OLEDs with a SiO/Al2O3 bilayer passivation layer displayed a remarkably increased device shelf life compared to devices prepared using Al2O3-only passivation. A MOCON test showed that the water vapor transmission rate (WVTR) of the SiO/Al2O3 bilayer film was 0.0033 g/(m(2) day), 2.3 times lower than the rate of a single Al2O3 barrier film. The results of our study demonstrated the multipurpose role of a SiO interlayer in plasma-based OLED passivation. The layer acted as a damage-free protective layer for the underlying OLED devices and an assistant layer to improve the upper barrier film performance.

  4. Deep-blue efficient OLED based on NPB with little efficiency roll-off under high current density

    NASA Astrophysics Data System (ADS)

    Liu, Jian

    2017-03-01

    NPB usually is used as a hole-transport layer in OLED. In fact, it is a standard pure blue-emission material. However, its light-emitting efficiency in OLED is low due to emissive nature of organic material. Herein, a deep-blue OLDE based on NPB was fabricated. The light-emitting efficiency of the device demonstrates a moderate value, and efficiency roll-off is little under high current density. The device demonstrates that the electroplex's emission decreases with increasing electric field intensity.

  5. Production of alkenes and novel secondary products by P450 OleTJE using novel H2 O2 -generating fusion protein systems.

    PubMed

    Matthews, Sarah; Tee, Kang Lan; Rattray, Nicholas J; McLean, Kirsty J; Leys, David; Parker, David A; Blankley, Richard T; Munro, Andrew W

    2017-03-01

    Jeotgalicoccus sp. 8456 OleTJE (CYP152L1) is a fatty acid decarboxylase cytochrome P450 that uses hydrogen peroxide (H2 O2 ) to catalyse production of terminal alkenes, which are industrially important chemicals with biofuel applications. We report enzyme fusion systems in which Streptomyces coelicolor alditol oxidase (AldO) is linked to OleTJE . AldO oxidizes polyols (including glycerol), generating H2 O2 as a coproduct and facilitating its use for efficient OleTJE -dependent fatty acid decarboxylation. AldO activity is regulatable by polyol substrate titration, enabling control over H2 O2 supply to minimize oxidative inactivation of OleTJE and prolong activity for increased alkene production. We also use these fusion systems to generate novel products from secondary turnover of 2-OH and 3-OH myristic acid primary products, expanding the catalytic repertoire of OleTJE .

  6. Highly efficient blue fluorescent OLEDs with doped double emitting layers based on p—n heterojunctions

    NASA Astrophysics Data System (ADS)

    Su, Yue-Ju; Wu, Xiao-Ming; Hua, Yu-Lin; Shen, Li-Ying; Jiao, Zhi-Qiang; Dong, Mu-Sen; Yin, Shou-Gen

    2012-05-01

    We fabricate a kind of novel efficient blue fluorescent organic light emitting device (OLED) based on p-n hetero-junctions composed of hole transporting layer (HTL) N, N'-bis(naphthalen-1-yl)-N, N'-bis(phenyl)-benzidine (NPB) and electron transporting layer (ETL) 4,7-diphnenyl-1,10-phenanthroline (BPhen), into which a new blue material, DNCA (a derivation of N6, N6, N12, N12-tetrap-tolylchrysene-6,12-diamine), is partially doped simultaneously, and double emitting layers are configured. With a turn-on voltage of 2.6 V at 1 cd/m2, this type of OLED presents a maximum luminance efficiency (ηmax) of 8.83 cd/A at 5.818 mA/cm2 and a maximum luminance of over 40000 cd/m2. Meanwhile, the Commission Internationale De L'Eclairage (CIE) coordinates of this device change slightly from (0.13, 0.27) to (0.13, 0.23) as the driving voltage increases from 3 V to 11 V. This improvement in the electroluminescent characteristics is attributed mainly to the ideal p—n heterojunction which can confine and distribute excitons evenly on two sides of the heterojunction interface so as to improve the carrier combination rate and expand the light-emitting region.

  7. Multi-Faceted Scientific Strategies Toward Better Solid-State Lighting of Phosphorescent OLEDs

    SciTech Connect

    Mohammad Omary; Bruce Gnade; Qi Wang; Oussama Elbjeirami; Chi Yang; Nigel Shepherd; Huiping Jia; Manuel Quevedo; Husam Alshareef; Minghang Li; Ming-Te Lin; Wei-Hsuan Chen; Iain Oswald; Pankaj Sinha; Ravi Arvapally; Usha Kaipa; John Determan; Sreekar Marpu; Roy McDougald; Gustavo Garza; Jason Halbert; Unnat Bhansali; Michael Perez

    2010-08-31

    This project has advanced solid-state lighting (SSL) by utilizing new phosphorescent systems for use in organic light-emitting diodes (OLEDs). The technical approach was two-fold: a) Targeted synthesis and screening of emitters designed to exhibit phosphorescence with maximized brightness in the solid state; and b) Construction and optimizing the performance of monochromatic and white OLEDs from the best new emitters to improve performance metrics versus the state of the art. The phosphorescent systems were screened candidates among a large variety of recentlysynthesized and newly-designed molecular and macromolecular metal-organic phosphors. The emitters and devices have been optimized to maximize light emission and color metrics, improve the long-term durability of emitters and devices, and reduce the manufacturing cost both by simplifying the process flow and by seeking less expensive device components than common ones. The project succeeded in all these goals upon comparison of the best materials and devices investigated vs. the state of the art of the technology.

  8. Synthesis and Electroluminescence Property of New Hexaphenyl Benzene Derivatives Including Emitting Core for OLED.

    PubMed

    Shin, Hwangyu; Kang, Hyeonmi; Kim, Jong-Hyung; Wang, Yun-Fan; Kim, Seungho; Kay, Kwang-Yol; Park, Jongwook

    2015-10-01

    Three new emitting compounds of 5P-2TPA, 5P-2An and 5P-2Py for OLED based on hexaphenyl benzene moiety were synthesized. Physical properties were systematically examined by the change of the substitution groups of the synthesized materials. Photoluminescence (PL) spectrum of the synthesized materials showed maximum emitting wavelengths of about 437~488 nm in solution state and 457~516 nm in film state, indicating blue emission color. OLED devices were fabricated by the synthesized compounds using vacuum deposition process as an emitting layer. Device structure was ITO/2-TNATA 60 nm/NPB 15 nm/EML 35 nm/TPBi 20 nm/LiF 1 nm/Al 200 nm. External quantum efficiencies and CIE values of 5P-2TPA, 5P-2An and 5P-2Py were 3.34, 1.06 and 2.06% and (0.14, 0.12), (0.23, 0.45) and (0.24, 0.45), respectively. The three compounds exhibited thermal stablility with high Td of 426 °C, 449 °C and 467 °C.

  9. Remote Steric Effect as a Facile Strategy for Improving the Efficiency of Exciplex-Based OLEDs.

    PubMed

    Hung, Wen-Yi; Wang, Ting-Chih; Chiang, Pin-Yi; Peng, Bo-Ji; Wong, Ken-Tsung

    2017-03-01

    This work reports a new strategy of introducing remote steric effect onto the electron donor for giving the better performance of the exciplex-based organic light-emitting device (OLED). The bulky triphenylsilyl group (SiPh3) was introduced onto the fluorene bridge of 4,4'-(9H-fluorene-9,9-diyl)bis(N,N-di-p-tolylaniline) (DTAF) to create remote steric interactions for increasing the possibility of effective contacts between electron-donating chromophores and acceptor molecules, rendering the resulting exciplex to have a higher photoluminescence quantum yield (PLQY). The green exciplex device based on DSDTAF:3N-T2T (1:1) as an emitting layer exhibits a low turn-on voltage of 2.0 V, high maximum efficiencies (13.2%, 42.9 cd A(-1), 45.5 lm W(-1)), which are higher than the device employed DTAF (without SiPh3 groups) (11.6%, 35.3 cd A(-1), 41.3 lm W(-1)) as donor under the same device structure. This strategy was further examined for blue exciplex, where the EQE was enhanced from 9.5% to 12.5% as the electron acceptor PO-T2T mixed with a tert-butyl group substituted carbazole-based donor (CPTBF) as the emitting exciplex in device. This strategy is simple and useful for developing high performance exciplex OLEDs.

  10. Transparent amorphous oxide semiconductors for organic electronics: Application to inverted OLEDs

    PubMed Central

    Hosono, Hideo; Toda, Yoshitake; Kamiya, Toshio; Watanabe, Satoru

    2017-01-01

    Efficient electron transfer between a cathode and an active organic layer is one key to realizing high-performance organic devices, which require electron injection/transport materials with very low work functions. We developed two wide-bandgap amorphous (a-) oxide semiconductors, a-calcium aluminate electride (a-C12A7:e) and a-zinc silicate (a-ZSO). A-ZSO exhibits a low work function of 3.5 eV and high electron mobility of 1 cm2/(V · s); furthermore, it also forms an ohmic contact with not only conventional cathode materials but also anode materials. A-C12A7:e has an exceptionally low work function of 3.0 eV and is used to enhance the electron injection property from a-ZSO to an emission layer. The inverted electron-only and organic light-emitting diode (OLED) devices fabricated with these two materials exhibit excellent performance compared with the normal type with LiF/Al. This approach provides a solution to the problem of fabricating oxide thin-film transistor-driven OLEDs with both large size and high stability. PMID:28028243

  11. Polymers Containing Diphenylvinyl-Substituted Indole Rings as Charge-Transporting Materials for OLEDs

    NASA Astrophysics Data System (ADS)

    Grigalevicius, S.; Zostautiene, R.; Sipaviciute, D.; Stulpinaite, B.; Volyniuk, D.; Grazulevicius, J. V.; Liu, L.; Xie, Z.; Zhang, B.

    2016-02-01

    Monomers and polymers containing electronically isolated diphenylvinyl-substituted indole rings were synthesized and characterized by nuclear magnetic resonance (NMR) and mass spectroscopies as well as by gel permeation chromatography. The polymers represent amorphous materials with glass transition temperatures of 91-109°C and thermal decomposition starting above 307°C. Electron photoemission spectra of thin films of the synthesized polymers revealed ionization potentials of 5.54-5.58 eV. The synthesized polymers were tested as hole-transporting materials in simple electroluminescent organic light-emitting diode (OLED) devices with tris(quinolin-8-olato)aluminium (Alq3) as an emitter as well as an electron-transporting layer. A green OLED device containing a hole-transporting layer of poly[1-(2,3-epithiopropyl)-2-methyl-3-(2,2-diphenylvinyl)índole] exhibited the best overall performance with a driving voltage of 4.0 V, maximum photometric efficiency of 2.8 cd/A and maximum brightness of about 4200 cd/m2.

  12. High-brightness and long-lifetime OLED with mixing layer technology

    NASA Astrophysics Data System (ADS)

    Lee, Jiun H.; Liu, S. W.; Huang, Ching-An; Yang, K. H.; Chang, Yih

    2004-09-01

    In this paper, we demonstrate organic light emitting devices (OLED) that exhibit high brightness, low driving voltage and long lifetime. Devices with the brightness of 10,000 cd/m2 can be achieved at 4 V by the use of the high mobility electron-transport layer (ETL) material, bis(10-hydroxybenzo[h]qinolinato)beryllium (Bebq2), and the mixing host (MH) technology. Electron mobility of Bebq2 is two orders of magnitude higher than that of the typical ETL material, tris-(8-hydroxyquinoline) aluminum (Alq3), from the time-of-flight (TOF) measurement and hence the driving voltage can be decreased. By co-evaporating the hole-transport layer (HTL) material and the ETL material as the host of the emitting layer, it reduces two volts in driving voltage because of its bipolar transport characteristics. MH technology can not only decrease the driving voltage, but also increase the device lifetime since it eliminates the sharp boundary of HTL/ETL interface and decreases the carriers piling up near this interface which causes the organic material degradation. Compared to the conventional heterojunction (HJ) OLED, operation lifetime of MH devices was enhanced by a factor of 4.

  13. Etch-less UV-NIL process for patterning photonic crystal structure onto OLED substrate

    NASA Astrophysics Data System (ADS)

    Jeong, Jun-ho; Jeon, Sohee; Shim, Jongyoup; Youn, Jae Ryoun; Park, Hyung-Dol; Kang, Jae-Wook; Kim, Jang-Joo; Kim, Ki-don; Choi, Dae-geun; Choi, Junhyuk; Lee, Dong-Il; Altun, Ali Ozhan; Lee, Soon-won; Lee, Eung-sug; Kim, Se-Heon; Lee, Yong-Hee

    2008-03-01

    An etch-less ultraviolet nanoimprint lithography (UV-NIL) process is proposed for patterning a photonic crystal (PC) structure onto an organic light-emitting diode (OLED) substrate. In a conventional UV-NIL, anisotropic etching is used to remove the residual layers and to transfer the patterns onto the substrate. The proposed process does not require an etching process. In the process, a stamp with nano-scale PC patterns is pressed on the dispensed resin and UV light is then exposed to cure the resin. After tens of seconds, the stamp is separated from the patterned polymer layer on the substrate. Finally, high-refractive index material is coated onto the layer. The refractive index of the polymer should be very similar to that of glass. The enhancement of the light extraction was assessed by the three-dimensional (3D) finite difference time domain (FDTD) method. The OLED was integrated on a nanoimprinted substrate and the electro-luminance intensity was found to have increased by as much as 50% compared to a conventional device.

  14. Ultrasmooth silver thin film electrodes with high polar liquid wettability for OLED microcavity application.

    PubMed

    Cioarec, Cristina; Melpignano, Patrizia; Gherardi, Nicolas; Clergereaux, Richard; Villeneuve, Christina

    2011-04-05

    For a lab-on-chip application, we fabricate a blue bottom emitting strong microcavity organic light emitting diode (OLED), using very smooth and optically thin (25 nm) silver film as anode on a glass substrate. To improve the hole injection in the OLED device, PEDOT-PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid)) has been used, so the silver anode must present not only a very smooth surface but also a strong adherence on the glass and a high wettability to allow a good PEDOT-PSS spin coating deposition. To obtain these physical properties, different 5 nm thick nucleation layers (germanium, chromium, and hydrogenated amorphous carbon) have been used to grow the silver thin films by e-beam deposition. The Ge/Ag bilayer presents all the desired properties: this bilayer, investigated by ellipsometry, optical profilometry, contact angle measurements, and XPS analysis, highlights an ultrasmooth surface correlated with the film growth mode and a high wettability related to its surface chemical composition.

  15. Photophysical properties and OLED performance of light-emitting platinum(II) complexes.

    PubMed

    Kourkoulos, Dimitrios; Karakus, Cüneyt; Hertel, Dirk; Alle, Ronald; Schmeding, Sebastian; Hummel, Johanna; Risch, Nikolaus; Holder, Elisabeth; Meerholz, Klaus

    2013-10-07

    The synthesis, photophysical properties and application as emitters in solution-processed multi-layer organic light-emitting diodes (OLEDs) of a series of blue-green to red light-emitting phosphorescent platinum(II) complexes are reported. These complexes consist of phenylisoquinoline, substituted phenylpyridines or tetrahydroquinolines as C^N cyclometalating ligands and dipivaloylmethane as an ancillary ligand. Depending on both the structure of the C^N cyclometalating ligands and the dopant concentration in the matrix, these platinum(II) complexes exhibit different aggregation tendencies. This property affects the photoluminescence spectra of the investigated compounds and colour-stability of the fabricated OLEDs. Using the blue-green to yellow-green emitting complexes, the best results were obtained with the 2-(4-trifluoromethylphenyl)-5,6,7,8-tetrahydroquinoline based platinum(II) complex. A maximum luminous efficiency of 4.88 cd A(-1) and a power efficiency of 4.65 lm W(-1), respectively, were achieved. Employing the red emitting phenylisoquinoline based complex as an emitter, colour-stable and efficient (4.71 cd A(-1), 5.12 lm W(-1)) devices were obtained.

  16. Fast responsive and highly efficient optical upconverter based on phosphorescent OLED.

    PubMed

    Chu, Xinbo; Guan, Min; Niu, Litao; Zeng, Yiping; Li, Yiyang; Zhang, Yang; Zhu, Zhanping; Wang, Baoqiang

    2014-11-12

    In this work, an organic-inorganic hybrid optical upconverter that can convert irradiated 980 nm IR light to 510 nm green phosphorescence sensitively was fabricated and studied. fac-Tris(2-phenylpyridine) iridium (Ir(ppy)3) doped 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) was used as emitting layer in the phosphorescent organic light-emitting diode (OLED) unit. The upconverter using a phosphorescent OLED as display unit can achieve a higher upconversion efficiency and a low power consumption when compared with the one using fluorescent. An upconversion efficiency of 4.8% can be achieved for phosphorescent device at 15 V, much higher than that of fluorescent one (2.0%). The upconverter's transient optical and electric response to IR pulse were also investigated for the first time. The response time was found to be influenced by IR intensity and applied voltage. It has a response time as short as 60 μs. The rapid response property of the upconverter makes it feasible to be applied to high-speed IR imaging systems.

  17. Low temperature transient response and electroluminescence characteristics of OLEDs based on Alq3

    NASA Astrophysics Data System (ADS)

    Yuan, Chao; Guan, Min; Zhang, Yang; Li, Yiyang; Liu, Shuangjie; Zeng, Yiping

    2017-08-01

    In this work, the organic light-emitting diodes (OLEDs) based on Alq3 are fabricated. In order to make clear the transport mechanism of carriers in organic light-emitting devices at low temperature, detailed electroluminescence transient response and the current-voltage-luminescence (I-V-L) characteristics under different temperatures in those OLEDs are investigated. It founds that the acceleration of brightness increases with increasing temperature is maximum when the temperature is 200 K and it is mainly affected by the electron transport layer (Alq3). The MoO3 injection layer and the electroluminescent layer have great influence on the delay time when the temperature is 200 K. Once the temperature is greater than 250 K, the delay time is mainly affected by the MoO3 injection layer. On the contrary, the fall time is mainly affected by the electroluminescent material. The Vf is the average growth rate of fall time when the temperature increases 1 K which represents the accumulation rate of carriers. The difference between Vf caused by the MoO3 injection layer is 0.52 us/K and caused by the electroluminescent material Ir(ppy)3 is 0.73 us/K.

  18. Benzobisoxazole cruciforms: A tunable, cross-conjugated platform for the generation of deep blue OLED materials

    DOE PAGES

    Chavez, III, Ramiro; Cai, Min; Tlach, Brian; ...

    2016-01-20

    Four new cross-conjugated small molecules based on a central benzo[1,2-d:4,5-d']bisoxazole moiety possessing semi-independently tunable HOMO and LUMO levels were synthesized and the properties of these materials were evaluated experimentally and theoretically. The molecules were thermally stable with 5% weight loss occurring well above 350 °C. The cruciforms all exhibited blue emission in solution ranging from 433–450 nm. Host–guest OLEDs fabricated from various concentrations of these materials using the small molecule host 4,4'-bis(9-carbazolyl)-biphenyl (CBP) exhibited deep blue-emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15 ≤ x ≤ 0.17, 0.05 ≤ y ≤ 0.11), and maximum luminance efficiencies as highmore » as ~2 cd A–1. Lastly, these results demonstrate the potential of benzobisoxazole cruciforms as emitters for developing high-performance deep blue OLEDs.« less

  19. Super multi-view three-dimensional display through spatial-spectrum time-multiplexing of planar aligned OLED microdisplays.

    PubMed

    Teng, Dongdong; Liu, Lilin; Wang, Biao

    2014-12-15

    Existing super multi-view (SMV) technologies depend on ultra-high resolution two-dimensional (2D) display panel or large number of 2D display panels to obtain dense sub-viewing-zones for constructing more natural three-dimensional (3D) display by pure spatial-multiplexing. Through gating the spatial-spectrum of each OLED microdisplay, the present work proposes a new SMV technology combining time- and spatial-multiplexing based on planar-aligned OLED microdisplays. The inherent light emission characteristics of OLED, i.e. large divergence angle, guarantees a homogeneous light intensity distribution on the spectrum plane, which is a necessary condition for successful time multiplexing. The developed system bears with low requirements on the number of 2D display panels. The factors influencing the lateral display resolution limit are discussed and the optimum value is deduced. Experimentally, a prototype system with 60 sub-viewing-zones is demonstrated by 12 OLED microdisplays. The horizontal interval between adjacent sub-viewing-zones is 1.6mm.

  20. The Enigmatic P450 Decarboxylase OleT Is Capable of, but Evolved To Frustrate, Oxygen Rebound Chemistry.

    PubMed

    Hsieh, Chun H; Huang, Xiongyi; Amaya, José A; Rutland, Cooper D; Keys, Carson L; Groves, John T; Austin, Rachel N; Makris, Thomas M

    2017-07-05

    OleT is a cytochrome P450 enzyme that catalyzes the removal of carbon dioxide from variable chain length fatty acids to form 1-alkenes. In this work, we examine the binding and metabolic profile of OleT with shorter chain length (n ≤ 12) fatty acids that can form liquid transportation fuels. Transient kinetics and product analyses confirm that OleT capably activates hydrogen peroxide with shorter substrates to form the high-valent intermediate Compound I and largely performs C-C bond scission. However, the enzyme also produces fatty alcohol side products using the high-valent iron oxo chemistry commonly associated with insertion of oxygen into hydrocarbons. When presented with a short chain fatty acid that can initiate the formation of Compound I, OleT oxidizes the diagnostic probe molecules norcarane and methylcyclopropane in a manner that is reminiscent of reactions of many CYP hydroxylases with radical clock substrates. These data are consistent with a decarboxylation mechanism in which Compound I abstracts a substrate hydrogen atom in the initial step. Positioning of the incipient substrate radical is a crucial element in controlling the efficiency of activated OH rebound.

  1. Solution structure of the C-terminal domain of Ole e 9, a major allergen of olive pollen

    PubMed Central

    Treviño, Miguel Á.; Palomares, Oscar; Castrillo, Inés; Villalba, Mayte; Rodríguez, Rosalía; Rico, Manuel; Santoro, Jorge; Bruix, Marta

    2008-01-01

    Ole e 9 is an olive pollen allergen belonging to group 2 of pathogenesis-related proteins. The protein is composed of two immunological independent domains: an N-terminal domain (NtD) with 1,3-β-glucanase activity, and a C-terminal domain (CtD) that binds 1,3-β-glucans. We have determined the three-dimensional structure of CtD-Ole e 9 (101 amino acids), which consists of two parallel α-helices forming an angle of ∼55°, a small antiparallel β-sheet with two short strands, and a 3–10 helix turn, all connected by long coil segments, resembling a novel type of folding among allergens. Two regions surrounded by aromatic residues (F49, Y60, F96, Y91 and Y31, H68, Y65, F78) have been localized on the protein surface, and a role for sugar binding is suggested. The epitope mapping of CtD-Ole e 9 shows that B-cell epitopes are mainly located on loops, although some of them are contained in secondary structural elements. Interestingly, the IgG and IgE epitopes are contiguous or overlapped, rather than coincident. The three-dimensional structure of CtD-Ole e 9 might help to understand the underlying mechanism of its biochemical function and to determine possible structure–allergenicity relationships. PMID:18096638

  2. Molecular basis of P450 OleTJE: an investigation of substrate binding mechanism and major pathways

    NASA Astrophysics Data System (ADS)

    Du, Juan; Liu, Lin; Guo, Li Zhong; Yao, Xiao Jun; Yang, Jian Ming

    2017-05-01

    Cytochrome P450 OleTJE has attracted much attention for its ability to catalyze the decarboxylation of long chain fatty acids to generate alkenes, which are not only biofuel molecule, but also can be used broadly for making lubricants, polymers and detergents. In this study, the molecular basis of the binding mechanism of P450 OleTJE for arachidic acid, myristic acid, and caprylic acid was investigated by utilizing conventional molecular dynamics simulation and binding free energy calculations. Moreover, random acceleration molecular dynamics (RAMD) simulations were performed to uncover the most probable access/egress channels for different fatty acids. The predicted binding free energy shows an order of arachidic acid < myristic acid < caprylic acid. Key residues interacting with three substrates and residues specifically binding to one of them were identified. The RAMD results suggest the most likely channel for arachidic acid, myristic acid, and caprylic acid are 2e/2b, 2a and 2f/2a, respectively. It is suggested that the reaction is easier to carry out in myristic acid bound system than those in arachidic acid and caprylic acid bound system based on the distance of Hβ atom of substrate relative to P450 OleTJE Compound I states. This study provided novel insight to understand the substrate preference mechanism of P450 OleTJE and valuable information for rational enzyme design for short chain fatty acid decarboxylation.

  3. Optogenetic Stimulation of Peripheral Vagus Nerves using Flexible OLED Display Technology to Treat Chronic Inflammatory Disease and Mental Health Disorders

    DTIC Science & Technology

    2016-03-31

    Optogenetic Stimulation of Peripheral Vagus Nerves using Flexible OLED Display Technology to Treat Chronic Inflammatory Disease and Mental Health...using a non-invasive drug-free optogenetics -based therapy that treats patients by optically stimulating afferent branches of the auricular vagus...therapeutic optical stimulation in optogenetically modified neural tissue. Keywords: Optogenetics ; neuromodulation; organic light emitting diode

  4. Study of the electroluminescence of highly stereoregular poly(N-pentenyl-carbazole) for blue and white OLEDs

    NASA Astrophysics Data System (ADS)

    Liguori, R.; Botta, A.; Pragliola, S.; Rubino, A.; Venditto, V.; Velardo, A.; Aprano, S.; Maglione, M. G.; Prontera, C. T.; De Girolamo Del Mauro, A.; Fasolino, T.; Minarini, C.

    2017-06-01

    The electroluminescence (EL) of isotactic and syndiotactic poly(N-pentenyl-carbazole) (PPK), achieved by coordination polymerization, is studied in order to investigate the interrelation between the polymer tacticity and their physical-chemical properties. The use of these polymers in organic light-emitting diode (OLED) fabrication is also explored. Thermal and x-ray diffraction analyses of PPKs show that the isotactic stereoisomer is semicrystalline, whereas the syndiotactic one is amorphous. Optical analysis of both stereoisomers, carried out on film samples, reveals the presence of two different excimers: ‘sandwich-like’ and ‘partially overlapping’. Nevertheless, the emission intensity ratio between ‘sandwich-like’ and ‘partially overlapping’ excimers is higher in the isotactic than in the syndiotactic stereoisomer. Using the synthesized polymers as OLED emitting layers, the influence of the polymer tacticity on the EL properties of the device is highlighted. In detail, while blue OLEDs are obtained by using the syndiotactic stereoisomer, OLEDs with a multilayer structure fabricated with the isotactic stereoisomer emit white light. The contribution of three different emissions (fluorescence, phosphorescence and electromer emissions) with comparable intensities to the detected white light is discussed.

  5. Molecular basis of P450 OleTJE: an investigation of substrate binding mechanism and major pathways.

    PubMed

    Du, Juan; Liu, Lin; Guo, Li Zhong; Yao, Xiao Jun; Yang, Jian Ming

    2017-03-25

    Cytochrome P450 OleTJE has attracted much attention for its ability to catalyze the decarboxylation of long chain fatty acids to generate alkenes, which are not only biofuel molecule, but also can be used broadly for making lubricants, polymers and detergents. In this study, the molecular basis of the binding mechanism of P450 OleTJE for arachidic acid, myristic acid, and caprylic acid was investigated by utilizing conventional molecular dynamics simulation and binding free energy calculations. Moreover, random acceleration molecular dynamics (RAMD) simulations were performed to uncover the most probable access/egress channels for different fatty acids. The predicted binding free energy shows an order of arachidic acid < myristic acid < caprylic acid. Key residues interacting with three substrates and residues specifically binding to one of them were identified. The RAMD results suggest the most likely channel for arachidic acid, myristic acid, and caprylic acid are 2e/2b, 2a and 2f/2a, respectively. It is suggested that the reaction is easier to carry out in myristic acid bound system than those in arachidic acid and caprylic acid bound system based on the distance of Hβ atom of substrate relative to P450 OleTJE Compound I states. This study provided novel insight to understand the substrate preference mechanism of P450 OleTJE and valuable information for rational enzyme design for short chain fatty acid decarboxylation.

  6. Thermally activated delayed fluorescence OLEDs with fully solution processed organic layers exhibiting nearly 10% external quantum efficiency.

    PubMed

    Albrecht, Ken; Matsuoka, Kenichi; Yokoyama, Daisuke; Sakai, Yoshiya; Nakayama, Akira; Fujita, Katsuhiko; Yamamoto, Kimihisa

    2017-02-21

    New solution processable and laminatable terminally modified carbazole-triazine thermally activated delayed fluorescence (TADF) dendrimers are reported. An OLED device with fully solution processed organic layers exhibited an external quantum efficiency of up to 9.4% at 100 cd m(-2).

  7. ["The Society for letters and natural science" The young Ole H. Mynster and the chemical revolution around 1800].

    PubMed

    Hansen, Sven Erik

    2015-01-01

    Ole H. Mynster (1772-1818) was a stepson of the leading physician at the Royal Frederik Hospital in Copenhagen. At an early age he became fond of zoology and mineralogy. He created "societies" in Enlightenment-style for boys and young people with lectures and collections. Later on a circle of talented young students, scientists and poets met in his small room at the hospital. Some of them with Ole Mynster as the head set up a modern scientific journal, Physicalsk, oeconomisk og medicochirurgisk Bibliotek for Danmark og Norge which encouraged the introduction of antiphlogistic chemistry. Ole Mynster became physician at the Royal Frederik Hospital and lecturer in clinical pharmacology. He wrote the first book in Danish on pharmacology based upon chemistry. In their memoirs, prominent members of his circle have told about him, and his son F.L. Mynster has written a draft for a biography. An overview of the activities within natural science and medicine of the young Ole Hieronymus Mynster is presented.

  8. Low cost solution-based materials processing methods for large area OLEDs and OFETs

    NASA Astrophysics Data System (ADS)

    Jeong, Jonghwa

    In Part 1, we demonstrate the fabrication of organic light-emitting devices (OLEDs) with precisely patterned pixels by the spin-casting of Alq3 and rubrene thin films with dimensions as small as 10 mum. The solution-based patterning technique produces pixels via the segregation of organic molecules into microfabricated channels or wells. Segregation is controlled by a combination of weak adsorbing characteristics of aliphatic terminated self-assembled monolayers (SAMs) and by centrifugal force, which directs the organic solution into the channel or well. This novel patterning technique may resolve the limitations of pixel resolution in the method of thermal evaporation using shadow masks, and is applicable to the fabrication of large area displays. Furthermore, the patterning technique has the potential to produce pixel sizes down to the limitation of photolithography and micromachining techniques, thereby enabling the fabrication of high-resolution microdisplays. The patterned OLEDs, based upon a confined structure with low refractive index of SiO2, exhibited higher current density than an unpatterned OLED, which results in higher electroluminescence intensity and eventually more efficient device operation at low applied voltages. We discuss the patterning method and device fabrication, and characterize the morphological, optical, and electrical properties of the organic pixels. In part 2, we demonstrate a new growth technique for organic single crystals based on solvent vapor assisted recrystallization. We show that, by controlling the polarity of the solvent vapor and the exposure time in a closed system, we obtain rubrene in orthorhombic to monoclinic crystal structures. This novel technique for growing single crystals can induce phase shifting and alteration of crystal structure and lattice parameters. The organic molecules showed structural change from orthorhombic to monoclinic, which also provided additional optical transition of hypsochromic shift from

  9. A hybrid simulated method for analyzing the optical efficiency of a head-mounted display with a quasi-crystal OLED panel.

    PubMed

    Chang, Kao-Der; Li, Chang-Yi; Pan, Jui-Wen; Cheng, Kuei-Yuan

    2014-03-10

    Organic light emitting diodes (OLEDs) with a quasi-crystal (QC) structure are analyzed and applied in a head-mounted display (HMD) system in this study. We adopt a hybrid simulated method to evaluate the light extraction efficiency (LEE) and far-field pattern in the air, and study the relationship between them. The simulation results show that OLEDs implanted with the QC structure can provide a collimated far-field pattern to increase the brightness. Using this 10-fold QC arrangement the maxima LEE of the OLEDs can be increased by 1.20 times. Compared with conventional OLEDs, the viewing angle of the OLED panel decreases from 120 degrees to 26 degrees with an improvement in the optical efficiency of the HMD system by 2.66 times. Moreover, the normalized on-axis intensity in the pupil of the eyepiece can be enlarged up to 3.95 times which suggests that the OLED panel can save 74.68% energy while achieving the same on-axis intensity as conventional OLEDs.

  10. Structural functionality, catalytic mechanism modeling and molecular allergenicity of phenylcoumaran benzylic ether reductase, an olive pollen (Ole e 12) allergen

    NASA Astrophysics Data System (ADS)

    Jimenez-Lopez, Jose C.; Kotchoni, Simeon O.; Hernandez-Soriano, Maria C.; Gachomo, Emma W.; Alché, Juan D.

    2013-10-01

    Isoflavone reductase-like proteins (IRLs) are enzymes with key roles in the metabolism of diverse flavonoids. Last identified olive pollen allergen (Ole e 12) is an IRL relevant for allergy amelioration, since it exhibits high prevalence among atopic patients. The goals of this study are the characterization of (A) the structural-functionality of Ole e 12 with a focus in its catalytic mechanism, and (B) its molecular allergenicity by extensive analysis using different molecular computer-aided approaches covering (1) physicochemical properties and functional-regulatory motifs, (2) sequence analysis, 2-D and 3D structural homology modeling comparative study and molecular docking, (3) conservational and evolutionary analysis, (4) catalytic mechanism modeling, and (5) sequence, structure-docking based B-cell epitopes prediction, while T-cell epitopes were predicted by inhibitory concentration and binding score methods. Structural-based detailed features, phylogenetic and sequences analysis have identified Ole e 12 as phenylcoumaran benzylic ether reductase. A catalytic mechanism has been proposed for Ole e 12 which display Lys133 as one of the conserved residues of the IRLs catalytic tetrad (Asn-Ser-Tyr-Lys). Structure characterization revealed a conserved protein folding among plants IRLs. However, sequence polymorphism significantly affected residues involved in the catalytic pocket structure and environment (cofactor and substrate interaction-recognition). It might also be responsible for IRLs isoforms functionality and regulation, since micro-heterogeneities affected physicochemical and posttranslational motifs. This polymorphism might have large implications for molecular differences in B- and T-cells epitopes of Ole e 12, and its identification may help designing strategies to improve the component-resolving diagnosis and immunotherapy of pollen and food allergy through development of molecular tools.

  11. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis.

    PubMed

    Goblirsch, Brandon R; Jensen, Matthew R; Mohamed, Fatuma A; Wackett, Lawrence P; Wilmot, Carrie M

    2016-12-23

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety-unusual for a thiolase-are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys(143)) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ(117)) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation.

  12. Molecular and biochemical characterization of the OLE-1 high-oleic castor seed (Ricinus communis L.) mutant.

    PubMed

    Venegas-Calerón, Mónica; Sánchez, Rosario; Salas, Joaquín J; Garcés, Rafael; Martínez-Force, Enrique

    2016-07-01

    The natural OLE-1 high-oleic castor mutant has been characterized, demonstrating that point mutations in the FAH12 gene are responsible for the high-oleic phenotype. The contribution of each mutation was evaluated by heterologous expression in yeast, and lipid studies in developing OLE-1 seeds provided new evidence of unusual fatty acids channeling into TAGs. Ricinus communis L. is a plant of the Euphorbiaceae family well known for producing seeds whose oil has a very high ricinoleic (12-hydroxyoctadecenoic) acid content. Castor oil is considered the only commercially renewable source of hydroxylated fatty acids, which have many applications as chemical reactants. Accordingly, there has been great interest in the field of plant lipid biotechnology to define how ricinoleic acid is synthesized, which could also provide information that might serve to increase the content of other unusual fatty acids in oil crops. Accordingly, we set out to study the biochemistry of castor oil synthesis by characterizing a natural castor bean mutant deficient in ricinoleic acid synthesis (OLE-1). This mutant accumulates high levels of oleic acid and displays remarkable alterations in its seed lipid composition. To identify enzymes that are critical for this phenotype in castor oil, we cloned and sequenced the oleate desaturase (FAD2) and hydroxylase (FAH12) genes from wild-type and OLE-1 castor bean plants and analyzed their expression in different tissues. Heterologous expression in yeast confirmed that three modifications to the OLE-1 FAH12 protein were responsible for its weaker hydroxylase activity. In addition, we studied the expression of the genes involved in this biosynthetic pathway at different developmental stages, as well as that of other genes involved in lipid biosynthesis, both in wild-type and mutant seeds.

  13. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis

    SciTech Connect

    Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2016-11-04

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys143) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ117) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation.

  14. Long-lived and highly efficient green and blue phosphorescent emitters and device architectures for OLED displays

    NASA Astrophysics Data System (ADS)

    Eickhoff, Christian; Murer, Peter; Geßner, Thomas; Birnstock, Jan; Kröger, Michael; Choi, Zungsun; Watanabe, Soichi; May, Falk; Lennartz, Christian; Stengel, Ilona; Münster, Ingo; Kahle, Klaus; Wagenblast, Gerhard; Mangold, Hannah

    2015-09-01

    In this paper, two OLED device concepts are introduced. First, classical phosphorescent green carbene emitters with unsurpassed lifetime, combined with low voltage and high efficiency are presented and the associated optimized OLED stacks are explained. Second, a path towards highly efficient, long-lived deep blue systems is shown. The high efficiencies can be reached by having the charge-recombination on the phosphorescent carbene emitter while at the same time short emissive lifetimes are realized by fast energy transfer to the fluorescent emitter, which eventually allows for higher OLED stability in the deep blue. Device architectures, materials and performance data are presented showing that carbene type emitters have the potential to outperform established phosphorescent green emitters both in terms of lifetime and efficiency. The specific class of green emitters under investigation shows distinctly larger electron affinities (2.1 to 2.5 eV) and ionization potentials (5.6 to 5.8 eV) as compared to the "standard" emitter Ir(ppy)3 (5.0/1.6 eV). This difference in energy levels requires an adopted OLED design, in particular with respect to emitter hosts and blocking layers. Consequently, in the diode setup presented here, the emitter species is electron transporting or electron trapping. For said green carbene emitters, the typical peak wavelength is 525 nm yielding CIE color coordinates of (x = 0.33, y = 0.62). Device data of green OLEDs are shown with EQEs of 26 %. Driving voltage at 1000 cd/m2 is below 3 V. In an optimized stack, a device lifetime of LT95 > 15,000 h (1000 cd/m2) has been reached, thus fulfilling AMOLED display requirements.

  15. 3,6,9,12-Tetrasubstituted chrysenes: synthesis, photophysical properties, and application as blue fluorescent OLED.

    PubMed

    Wu, Tien-Lin; Chou, Ho-Hsiu; Huang, Pei-Yun; Cheng, Chien-Hong; Liu, Rai-Shung

    2014-01-03

    A short synthesis of unsubstituted chrysene is described to provide a cheap source of this compound. This chrysene was used to prepare 3,6,9,12-tetrabromochrysene, which was subsequently transformed into various 3,6,9,12-tetrasubstituted chrysenes bearing four aryl, alkynyl, or amino groups by means of the Suzuki, Sonogashira, or Buchwald-Hartwig coupling reaction, respectively. These substituents result in large bathochromic shifts in the chrysene absorption and emission spectra. These new chrysene derivatives show blue fluorescent emission (401-471 nm) with high quantum yields (0.44-0.87). DFT calculations on these chrysenes rationalize well the substituent effects on their HOMO and LUMO energy levels. One representative chrysene (6g) was used as a blue fluorescent emitter in an OLED device that showed an outstanding external quantum efficiency (η = 6.31%) with blue emission [CIE (x, y) = (0.13, 0.20)] and a low turn-on voltage (3.0 V).

  16. A solution processed top emission OLED with transparent carbon nanotube electrodes.

    PubMed

    Chien, Yu-Mo; Lefevre, Florent; Shih, Ishiang; Izquierdo, Ricardo

    2010-04-02

    Top emission organic light emitting diodes (OLEDs) with carbon nanotubes (CNTs) as top electrodes were fabricated and characterized. Devices were fabricated on glass substrates with evaporated bottom Al/LiF cathodes, a spin coated organic emissive layer and a PEDOT-PSS hole injection layer. Transparent thin CNT films were deposited on top of the emission layer to form the anode by micro-contact printing with a polydimethylsiloxane stamp. A very good device performance was obtained, with a peak luminance of 3588 cd m(-2) and a maximum current efficiency of 1.24 cd A(-1). This work shows the possibility of using CNTs as transparent electrodes to replace ITO in organic semiconductor devices. Furthermore, the top emission nature of such devices offers a broader range of applications of CNTs on any type of substrate. By combining with solution processed organic materials, it is anticipated that lower cost fabrication will be possible through roll-to-roll manufacture.

  17. Recent developments in materials and processes for ink jet printing high resolution polymer OLED displays

    NASA Astrophysics Data System (ADS)

    Carter, Julian; Wehrum, Anja; Dowling, Mark C.; Cacheiro-Martinez, Martin; Baynes, Nick d. B.

    2003-03-01

    The fabrication of high resolution light emitting polymer (LEP) OLED displays using ink jet printing to deposit the hole conducting and conjugated polymer electroluminescent components has required the development of both printing and ink technology. We review the issues associated with meeting the technology requirement and split these into the areas of ink delivery, getting the correct volume out of ink jet nozzles with well defined velocity and direction; surface energy considerations to maximize aperture ratio and display resolution; solution drying to form flat films and solution formulation to create polymer films that perform as well as films created by conventional spin coating. In addition we will describe the current status of the technology both in terms of polymer performance for both passive and active matrix applications, printing technology and polymer ink performance.

  18. A solution processed top emission OLED with transparent carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Chien, Yu-Mo; Lefevre, Florent; Shih, Ishiang; Izquierdo, Ricardo

    2010-04-01

    Top emission organic light emitting diodes (OLEDs) with carbon nanotubes (CNTs) as top electrodes were fabricated and characterized. Devices were fabricated on glass substrates with evaporated bottom Al/LiF cathodes, a spin coated organic emissive layer and a PEDOT-PSS hole injection layer. Transparent thin CNT films were deposited on top of the emission layer to form the anode by micro-contact printing with a polydimethylsiloxane stamp. A very good device performance was obtained, with a peak luminance of 3588 cd m - 2 and a maximum current efficiency of 1.24 cd A - 1. This work shows the possibility of using CNTs as transparent electrodes to replace ITO in organic semiconductor devices. Furthermore, the top emission nature of such devices offers a broader range of applications of CNTs on any type of substrate. By combining with solution processed organic materials, it is anticipated that lower cost fabrication will be possible through roll-to-roll manufacture.

  19. White emission from a single-component single-layer solution processed OLED

    NASA Astrophysics Data System (ADS)

    Coya, Carmen; Ramos, Maria M.; Luna, Xenia; Álvarez, Angel Luis; de Andrés, Alicia; Blanco, Raúl; Juárez, Rafael; Gómez, Rafael; Segura, Jose Luis

    2009-08-01

    We report white electroluminescence from a single component-single layer solution processed organic light emitting diodes (OLEDs). In this work, we have fabricated and characterized OLEDs based on a single polymer synthesized by incorporating a small amount of the orange-light emitting chromophore 1,8-Naphtalimide derivative as side chain to poly(fluorene-alt-phenylene) (PFP). The structure of the devices is ITO/PEDOT:PSS/Active layer/Al. The dopant unit was convalenttly attached to the side chain of polyfluorene by alkyl spacers. We have fabricated devices with different amounts of the orange chromophore (0, 0.0005, 0.005, 0.02 and 0.08 in weight) as well as a device based on a physical blend in the same proportion of 0.08 for comparison purposes. Absorption and Photoluminescence (PL) studies in thin films show no significant interaction can be observed between both moieties in the ground state, but after photoexcitation an efficient energy transfer takes place from PFP to the orange chromophore. We have observed a more efficient energy transfer in these compounds than for physical mixtures of the two chromophores due to a phase separation effect in the blend confirmed by the optical measurements and ESEM analysis, obtaining energy transfer even in diluted solutions from the intramolecular interaction in the copolymers. With this very simple device structure, white light with Commission Internationale de l'Eclairage (CIE) coordenates (0.34;0.43) is obtained for the electroluminescence (EL) emission and turn on voltage of 6 V for the device based on the copolymer with x = 0.02, together with a good match in the EL and PL spectra indicative that two emissions are produced by the same species, making this material very suitable for large area solution processed devices in solid state illumination.

  20. Bright coppertunities: efficient OLED devices with copper(I)iodide-NHetPHOS-emitters

    NASA Astrophysics Data System (ADS)

    Wallesch, Manuela; Volz, Daniel; Fléchon, Charlotte; Zink, Daniel M.; Bräse, Stefan; Baumann, Thomas

    2014-10-01

    The mass market application of OLEDs is currently hindered because i) the materials are too expensive and contain rare metals such as iridium and ii) current processing techniques are elaborate and cannot easily be up-scaled. Solution processable Cu(I)-complexes promise to solve both problems with one blow: Copper is an abundant metal, which offers new opportunities to develop materials for OLEDs. Due to their structural diversity, Cu(I) emitters allow for the design of materials with tunable properties. Beside this, it is also possible to adjust solution properties and introduce functionalities for cross-linking. The new materials feature exciting photophysical properties such as PLQY values close to unity and a tunable emission. The emission decay times are in the range of common emitters or lower, which is expected to reduce efficiency roll-off at high driving voltages. Cu(I)-complexes often feature thermally-activated delayed fluorescence (TADF). As a consequence, they can make use of triplet and singlet excitons in a process called Singlet Harvesting, which paves the way for high efficiencies. Unlike Ir(III)-complexes such as Irppy3, triplet-triplet annihilation does not occur when using Cu(I), even in very high doping concentrations. The feasibility of NHetPHOS-type Cu(I)-complexes is demonstrated as well as strategies that enable a smart crosslinking process, where the Cu(I) emitters themselves play an important role. In addition, high-brightness devices, which were operated at medium voltages, yielding 50.000 cd m-2 are shown. In a showcase example, we recently presented a device with an external quantum efficiency greater than 20% with a solution processed Cu(I)-PyrPHOS-device without using outcoupling techniques.

  1. Sorting of large-diameter semiconducting carbon nanotube and printed flexible driving circuit for organic light emitting diode (OLED)

    NASA Astrophysics Data System (ADS)

    Xu, Wenya; Zhao, Jianwen; Qian, Long; Han, Xianying; Wu, Liangzhuan; Wu, Weichen; Song, Minshun; Zhou, Lu; Su, Wenming; Wang, Chao; Nie, Shuhong; Cui, Zheng

    2014-01-01

    A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10-3 A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 104 and output current up to 3.5 × 10-4 A at Vscan = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications.A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10-3 A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 104 and output current up to 3.5 × 10-4 A at Vscan = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving

  2. Spirobifluorene-2,7-dicarbazole-4'-phosphine Oxide as Host for High-Performance Single-Layer Green Phosphorescent OLED Devices.

    PubMed

    Thiery, Sébastien; Tondelier, Denis; Geffroy, Bernard; Jacques, Emmanuel; Robin, Malo; Métivier, Rémi; Jeannin, Olivier; Rault-Berthelot, Joëlle; Poriel, Cyril

    2015-10-02

    A new host material based on the 2,7,4'-substituted spirobifluorene platform has been designed and used in single-layer phosphorescent OLED with very high efficiency (EQE = 13.2%) and low turn-on voltage (2.4 V). This performance is among the best reported for green single-layer PhOLEDs and may open new avenues in the design of host materials for single-layer devices.

  3. Structure and Biochemical Properties of the Alkene Producing Cytochrome P450 OleTJE (CYP152L1) from the Jeotgalicoccus sp. 8456 Bacterium*

    PubMed Central

    Belcher, James; McLean, Kirsty J.; Matthews, Sarah; Woodward, Laura S.; Fisher, Karl; Rigby, Stephen E. J.; Nelson, David R.; Potts, Donna; Baynham, Michael T.; Parker, David A.; Leys, David; Munro, Andrew W.

    2014-01-01

    The production of hydrocarbons in nature has been documented for only a limited set of organisms, with many of the molecular components underpinning these processes only recently identified. There is an obvious scope for application of these catalysts and engineered variants thereof in the future production of biofuels. Here we present biochemical characterization and crystal structures of a cytochrome P450 fatty acid peroxygenase: the terminal alkene forming OleTJE (CYP152L1) from Jeotgalicoccus sp. 8456. OleTJE is stabilized at high ionic strength, but aggregation and precipitation of OleTJE in low salt buffer can be turned to advantage for purification, because resolubilized OleTJE is fully active and extensively dissociated from lipids. OleTJE binds avidly to a range of long chain fatty acids, and structures of both ligand-free and arachidic acid-bound OleTJE reveal that the P450 active site is preformed for fatty acid binding. OleTJE heme iron has an unusually positive redox potential (−103 mV versus normal hydrogen electrode), which is not significantly affected by substrate binding, despite extensive conversion of the heme iron to a high spin ferric state. Terminal alkenes are produced from a range of saturated fatty acids (C12–C20), and stopped-flow spectroscopy indicates a rapid reaction between peroxide and fatty acid-bound OleTJE (167 s−1 at 200 μm H2O2). Surprisingly, the active site is highly similar in structure to the related P450BSβ, which catalyzes hydroxylation of fatty acids as opposed to decarboxylation. Our data provide new insights into structural and mechanistic properties of a robust P450 with potential industrial applications. PMID:24443585

  4. Structure and biochemical properties of the alkene producing cytochrome P450 OleTJE (CYP152L1) from the Jeotgalicoccus sp. 8456 bacterium.

    PubMed

    Belcher, James; McLean, Kirsty J; Matthews, Sarah; Woodward, Laura S; Fisher, Karl; Rigby, Stephen E J; Nelson, David R; Potts, Donna; Baynham, Michael T; Parker, David A; Leys, David; Munro, Andrew W

    2014-03-07

    The production of hydrocarbons in nature has been documented for only a limited set of organisms, with many of the molecular components underpinning these processes only recently identified. There is an obvious scope for application of these catalysts and engineered variants thereof in the future production of biofuels. Here we present biochemical characterization and crystal structures of a cytochrome P450 fatty acid peroxygenase: the terminal alkene forming OleTJE (CYP152L1) from Jeotgalicoccus sp. 8456. OleTJE is stabilized at high ionic strength, but aggregation and precipitation of OleTJE in low salt buffer can be turned to advantage for purification, because resolubilized OleTJE is fully active and extensively dissociated from lipids. OleTJE binds avidly to a range of long chain fatty acids, and structures of both ligand-free and arachidic acid-bound OleTJE reveal that the P450 active site is preformed for fatty acid binding. OleTJE heme iron has an unusually positive redox potential (-103 mV versus normal hydrogen electrode), which is not significantly affected by substrate binding, despite extensive conversion of the heme iron to a high spin ferric state. Terminal alkenes are produced from a range of saturated fatty acids (C12-C20), and stopped-flow spectroscopy indicates a rapid reaction between peroxide and fatty acid-bound OleTJE (167 s(-1) at 200 μm H2O2). Surprisingly, the active site is highly similar in structure to the related P450BSβ, which catalyzes hydroxylation of fatty acids as opposed to decarboxylation. Our data provide new insights into structural and mechanistic properties of a robust P450 with potential industrial applications.

  5. Endolysosomal Degradation of Allergenic Ole e 1-Like Proteins: Analysis of Proteolytic Cleavage Sites Revealing T Cell Epitope-Containing Peptides.

    PubMed

    Wildner, Sabrina; Elsässer, Brigitta; Stemeseder, Teresa; Briza, Peter; Soh, Wai Tuck; Villalba, Mayte; Lidholm, Jonas; Brandstetter, Hans; Gadermaier, Gabriele

    2017-08-16

    Knowledge of the susceptibility of proteins to endolysosomal proteases provides valuable information on immunogenicity. Though Ole e 1-like proteins are considered relevant allergens, little is known about their immunogenic properties and T cell epitopes. Thus, six representative molecules, i.e., Ole e 1, Fra e 1, Sal k 5, Che a 1, Phl p 11 and Pla l 1, were investigated. Endolysosomal degradation and peptide generation were simulated using microsomal fractions of JAWS II dendritic cells. Kinetics and peptide patterns were evaluated by gel electrophoresis and mass spectrometry. In silico MHC (major histocompatibility complex) class II binding prediction was performed with ProPred. Cleavage sites were assigned to the primary and secondary structure, and in silico docking experiments between the protease cathepsin S and Ole e 1 were performed. Different kinetics during endolysosomal degradation were observed while similar peptide profiles especially at the C-termini were detected. Typically, the identified peptide clusters comprised the previously-reported T cell epitopes of Ole e 1, consistent with an in silico analysis of the T cell epitopes. The results emphasize the importance of the fold on allergen processing, as also reflected by conserved cleavage sites located within the large flexible loop. In silico docking and mass spectrometry results suggest that one of the first Ole e 1 cleavages might occur at positions 107-108. Our results provided kinetic and structural information on endolysosomal processing of Ole e 1-like proteins.

  6. Impedance spectroscopy of organic hetero-layer OLEDs as a probe for charge carrier injection and device degradation

    NASA Astrophysics Data System (ADS)

    Nowy, Stefan; Ren, Wei; Wagner, Julia; Weber, Josef A.; Brütting, Wolfgang

    2009-08-01

    Impedance spectroscopy (IS) is a powerful method for characterizing the electrical properties of materials and their interfaces. In this study we use IS to investigate the charge carrier injection properties of different anodes and anode treatments in bottom-emitting organic light-emitting diodes (OLEDs). These are ITO-based (indium tin oxide) hetero-layer devices with TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4-diamine) as hole transporting layer (HTL) and Alq3 (tris-(8-hydroxyquinoline) aluminum) as emission and electron transporting layer (EML and ETL, respectively). A detailed analysis of the capacitance as function of frequency and DC bias yields information about trapped and interfacial charges as well as the dynamics of injected charges. Furthermore, we use IS to study degradation processes in OLEDs.

  7. Self-assembled monolayer modified MoO3/Au/MoO3 multilayer anodes for high performance OLEDs

    NASA Astrophysics Data System (ADS)

    Jeong, Daekyun; Lim, Chefwi; Kim, Myeonggi; Jeong, Kyunghoon; Kim, Jae-Hun; Kim, Jiyoung; Park, Jin-Goo; Min, Kyeong-Sik; Lee, Jaegab

    2017-01-01

    We control the work function and the surface energy of the MoO3/Au/MoO3 (MAM) anode of OLEDs by modifying the top MoO3 layer via vapor phase deposition. The performance and stability of the device are significantly altered depending on the dipole direction of the selfassembled monolayer (SAM) with permanent dipole moment inserted between N,N'-Bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine (NPB) film and a MAM anode as well as on the interfacial wetting between the SAM and NPB layer. A CF3-terminated monolayer on a MAM electrode improved the performance and stability of the OLEDs relative to a reference device with only a MAM electrode, demonstrating that coating with SAMs via vapor phase deposition is an effective method to engineer the interface of MAM electrode optoelectronic devices. [Figure not available: see fulltext.

  8. Fabrication and Characterization of New Hybrid Organic Light Emitting Diode (OLED): Europium-picrate-triethylene oxide Complex

    SciTech Connect

    Sarjidan, M. A. Mohd; Abu Zakaria, N. Z. A.; Abd. Majid, W. H.; Kusrini, Eny; Saleh, M. I.

    2009-07-07

    Thin-film light emitting devices based on organic materials have attracted vast interest in applications such as light emitting diode (LED) and flat-panel display. The organic material can be attached with inorganic material to enhance the performance of the light emitting device. A hybrid OLED based on a new complex of europium picrate (Eu-pic) with triethylene oxide (EO3) ligand is fabricated. The OLED is fabricated by using spin coating technique with acetone as the solvent and aluminum as the top electrode. The optical, photoluminescence (PL) and electrical properties of the sample are carried out by UV-Vis spectroscopy (Jasco V-750), luminescence spectroscopy (Perkin Elmer LS-500) and source measure unit (SMU)(Keithly), respectively.

  9. Structurally integrated organic light-emitting device (OLED)-based multianalyte sensing through analyte-oxidase interactions

    NASA Astrophysics Data System (ADS)

    Shinar, Ruth; Qian, Chengliang; Cai, Yuankun; Zhou, Zhaoqun; Choudhury, Bhaskar; Shinar, Joseph

    2005-11-01

    The development of a compact structurally integrated platform for detection of multianalytes that consume oxygen in the presence of specific oxidase enzymes is described. The detection is based on monitoring the photoluminescence (PL) intensity or lifetime of a sensing element based on the oxygen sensitive dye Pt octaethyl porphyrin (PtOEP). The excitation source for the PL is an array of individually addressable green OLED pixels. The analytes are gas- phase and dissolved oxygen, glucose, lactate, and alcohol. The sensing element for each analyte includes a layer of PtOEP-doped polystyrene, whose PL lifetime decreases with increasing O II level, and a film or solution containing the oxidase enzyme specific to the analyte. Each sensing element is associated with two addressable ~2x2 mm2 OLED pixels. The operation and performance metrics of the sensor under various conditions are described and discussed.

  10. Technology and design of an active-matrix OLED on crystalline silicon direct-view display for a wristwatch computer

    NASA Astrophysics Data System (ADS)

    Sanford, James L.; Schlig, Eugene S.; Prache, Olivier; Dove, Derek B.; Ali, Tariq A.; Howard, Webster E.

    2002-02-01

    The IBM Research Division and eMagin Corp. jointly have developed a low-power VGA direct view active matrix OLED display, fabricated on a crystalline silicon CMOS chip. The display is incorporated in IBM prototype wristwatch computers running the Linus operating system. IBM designed the silicon chip and eMagin developed the organic stack and performed the back-end-of line processing and packaging. Each pixel is driven by a constant current source controlled by a CMOS RAM cell, and the display receives its data from the processor memory bus. This paper describes the OLED technology and packaging, and outlines the design of the pixel and display electronics and the processor interface. Experimental results are presented.

  11. Ole e 13 is the unique food allergen in olive: Structure-functional, substrates docking, and molecular allergenicity comparative analysis.

    PubMed

    Jimenez-Lopez, J C; Robles-Bolivar, P; Lopez-Valverde, F J; Lima-Cabello, E; Kotchoni, S O; Alché, J D

    2016-05-01

    Thaumatin-like proteins (TLPs) are enzymes with important functions in pathogens defense and in the response to biotic and abiotic stresses. Last identified olive allergen (Ole e 13) is a TLP, which may also importantly contribute to food allergy and cross-allergenicity to pollen allergen proteins. The goals of this study are the characterization of the structural-functionality of Ole e 13 with a focus in its catalytic mechanism, and its molecular allergenicity by extensive analysis using different molecular computer-aided approaches covering a) functional-regulatory motifs, b) comparative study of linear sequence, 2-D and 3D structural homology modeling, c) molecular docking with two different β-D-glucans, d) conservational and evolutionary analysis, e) catalytic mechanism modeling, and f) IgE-binding, B- and T-cell epitopes identification and comparison to other allergenic TLPs. Sequence comparison, structure-based features, and phylogenetic analysis identified Ole e 13 as a thaumatin-like protein. 3D structural characterization revealed a conserved overall folding among plants TLPs, with mayor differences in the acidic (catalytic) cleft. Molecular docking analysis using two β-(1,3)-glucans allowed to identify fundamental residues involved in the endo-1,3-β-glucanase activity, and defining E84 as one of the conserved residues of the TLPs responsible of the nucleophilic attack to initiate the enzymatic reaction and D107 as proton donor, thus proposing a catalytic mechanism for Ole e 13. Identification of IgE-binding, B- and T-cell epitopes may help designing strategies to improve diagnosis and immunotherapy to food allergy and cross-allergenic pollen TLPs.

  12. Sticker-type Alq(3)-based OLEDs based on printable ultrathin substrates in periodically anchored and suspended configurations.

    PubMed

    Yun, Su Ok; Hwang, Youngkyu; Park, Jeongpil; Jeong, Yunkyung; Kim, Suk Ho; Noh, Byeong Il; Jung, Hoon Sun; Jang, Hun Soo; Hyun, Yujun; Choa, Sung-Hoon; Ko, Heung Cho

    2013-10-18

    Introducing two-dimensional post arrays and a water-soluble sacrificial layer between an ultrathin substrate and a handling substrate provides controllability of the interfacial adhesion in a stable manner. The periodically anchored and suspended configuration after the chemical etching process facilitates the development of, for example, printable Alq3 -based OLEDs that can be attached to unconventional surfaces. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    NASA Astrophysics Data System (ADS)

    Xiao, Teng

    Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxy-thiophene):polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3-hexylthiophene) (P3HT):phenyl-C 61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A

  14. Using deposition rate as a means to alter the properties of small molecule organic glasses for OLED applications

    NASA Astrophysics Data System (ADS)

    Kearns, Kenneth; Krzyskowski, Paige; Devereaux, Zachary

    2015-03-01

    Organic light emitting diode (OLED) devices rely on vapor-deposited, small molecule organic glasses. Recent work has shown that deposition condition plays a critical role in altering OLED device performance. Here it will be shown that the deposition rate alters the onset and fictive temperatures measured by differential scanning calorimetry (DSC) of the deposited glass. Glasses of the common hole transport materials NPD and TPD were prepared with onset temperatures 17 and 16 K higher, respectively, than the ordinary glass prepared by cooling the supercooled liquid. The thermal stability of glasses in functioning devices can be underestimated due to increases in onset temperature relative to Tg. The fictive temperatures for NPD and TPD were 32 and 27 K lower, respectively, than the Tg of the ordinary glass. These results are consistent with literature reports on other non-OLED glasses where enhanced surface mobility allowed for glasses with similar properties to be made. Ellipsometry studies on NPD showed that the fictive and onset temperatures were consistent with the DSC results. Additionally, the modeled birefringence of the as-deposited NPD glass was non-zero and quickly decreased upon heating above the onset temperature, which has implications for device performance. Formerly at Department of Chemistry, Saginaw Valley State University.

  15. The amino acid sequence of Ole e I, the major allergen from olive tree (Olea europaea) pollen.

    PubMed

    Villalba, M; Batanero, E; López-Otín, C; Sánchez, L M; Monsalve, R I; González de la Peña, M A; Lahoz, C; Rodríguez, R

    1993-09-15

    The complete primary structure of the major allergen from Olea europaea (olive tree) pollen, Ole e I (IUIS nomenclature), has been determined. The amino acid sequence was established by automated Edman degradation of the reduced and alkylated molecule as well as of selected fragments obtained by proteolytic digestions. Ole e I contains a single polypeptide chain of 145 amino acid residues with a calculated molecular mass of 16331 Da. No free sulfhydryl groups have been detected in the native protein. The molecule contains a putative glycosylation site. A high degree of microheterogeneity has been observed, mainly centered in the first 33% of the molecule. Comparison of Ole e I sequence with protein sequence databases showed no similarity with other known allergens. However, it has a 36% and 38% sequence identity with the putative polypeptide structures, deduced, respectively, from nucleotide sequences of genes isolated from tomato anthers and corn pollen, which have been suggested to be involved in the growing of the pollen tube. Therefore, the olive tree allergen may be a constitutive protein of the pollen involved in reproductive functions.

  16. Structurally Integrated Photoluminescence-Based Lactate Sensor Using Organic Light Emitting Devices (OLEDs) as the Light Source

    SciTech Connect

    Qian, Chengliang

    2006-01-01

    Multianalyte bio(chemical) sensors are extensively researched for monitoring analytes in complex systems, such as blood serum. As a step towards developing such multianalyte sensors, we studied a novel, structurally integrated, organic light emitting device (OLED)-based sensing platform for detection of lactate. Lactate biosensors have attracted numerous research efforts, due to their wide applications in clinical diagnosis, athletic training and food industry. The OLED-based sensor is based on monitoring the oxidation reaction of lactate, which is catalyzed by the lactate oxidase (LOX) enzyme. The sensing component is based on an oxygen-sensitive dye, Platinum octaethyl porphyrin (PtOEP), whose photoluminescence (PL) lifetime τ decreases as the oxygen level increases. The PtOEP dye was embedded in a thin film polystyrene (PS) matrix; the LOX was dissolved in solution or immobilized in a sol-gel matrix. τ was measured as a function of the lactate concentration; as the lactate concentration increases, τ increases due to increased oxygen consumption. The sensors performance is discussed in terms of the detection sensitivity, dynamic range, and response time. A response time of ~32 sec was achieved when the LOX was dissolved in solution and kept in a closed cell. Steps towards development of a multianalyte sensor array using an array of individually addressable OLED pixels were also presented.

  17. Organic solution-processible electroluminescent molecular glasses for non-doped standard red OLEDs with electrically stable chromaticity

    SciTech Connect

    Bi, Xiaoman; Zuo, Weiwei; Liu, Yingliang Zhang, Zhenru; Zeng, Cen; Xu, Shengang; Cao, Shaokui

    2015-10-15

    Highlights: • The D–A–D electroluminescent molecular glasses are synthesized. • Non-doped red electroluminescent film is fabricated by spin-coating. • Red OLED shows stable wavelength, luminous efficiency and chromaticity. • CIE1931 coordinate is in accord with standard red light in PAL system. - Abstract: Organic light-emitting molecular glasses (OEMGs) are synthesized through the introduction of nonplanar donor and branched aliphatic chain into electroluminescent emitters. The target OEMGs are characterized by {sup 1}H NMR, {sup 13}C NMR, IR, UV–vis and fluorescent spectra as well as elemental analysis, TG and DSC. The results indicated that the optical, electrochemical and electroluminescent properties of OEMGs are adjusted successfully by the replacement of electron-donating group. The non-doped OLED device with a standard red electroluminescent emission is achieved by spin-coating the THF solution of OEMG with a triphenylamine moiety. This non-doped red OLED device takes on an electrically stable electroluminescent performance, including the stable maximum electroluminescent wavelength of 640 nm, the stable luminous efficiency of 2.4 cd/A and the stable CIE1931 coordinate of (x, y) = (0.64, 0.35), which is basically in accord with the CIE1931 coordinate (x, y) = (0.64, 0.33) of standard red light in PAL system.

  18. Investigating the impacts of LLJs and OLEs on ABL exchanges and transports using an airborne Doppler wind lidar

    NASA Astrophysics Data System (ADS)

    Emmitt, G. D.; Foster, R. C.; Godwin, K.; Greco, S.

    2013-12-01

    An airborne Doppler wind lidar (ADWL) has been used for more than a decade to investigate the Atmospheric Boundary Layer (ABL) in the coastal region of central California. The frequent detection of Low Level Jets (LLJs) and Organized Large Eddies (OLEs) has made a strong case for a focused study on the role these structures play in modulating the exchange of mass, momentum and energy between the atmosphere and the underlying land/water. As the ADWL provides high resolution wind and aerosol observations, aircraft in situ instrumentation measures state variables (10Hz) to enable flux computations within the ABL. This combination is ideally suited to relating both Eddy Diffusivity and Mass Fluxes to the presence and degree of organized structures such as LLJs, OLEs scaled to the depth of the Boundary Layer, OLEs scaled by the LLJ and convective 'plumes'. The recent addition of a modified 'cruise missile' towed below the aircraft, within 10 meters of the surface, promises to provide an additional and unique set of observations. Results from several field experiments using an ADWL installed on a Twin Otter (TODWL) will be presented with a focus upon the visualization of ABL structures and the interpretation of direct measurements of wind velocity, turbulence and aerosol distributions. Observations and fluxes derived from the Twin Otter's gust probe will be examined in terms of the DWL resolved ABL features.

  19. Sorting of large-diameter semiconducting carbon nanotube and printed flexible driving circuit for organic light emitting diode (OLED).

    PubMed

    Xu, Wenya; Zhao, Jianwen; Qian, Long; Han, Xianying; Wu, Liangzhuan; Wu, Weichen; Song, Minshun; Zhou, Lu; Su, Wenming; Wang, Chao; Nie, Shuhong; Cui, Zheng

    2014-01-01

    A novel approach was developed to sort a large-diameter semiconducting single-walled carbon nanotube (sc-SWCNT) based on copolyfluorene derivative with high yield. High purity sc-SWCNTs inks were obtained by wrapping arc-discharge SWCNTs with poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) aided by sonication and centrifugation in tetrahydrofuran (THF). The sorted sc-SWCNT inks and nanosilver inks were used to print top-gated thin-film transistors (TFTs) on flexible substrates with an aerosol jet printer. The printed TFTs demonstrated low operating voltage, small hysteresis, high on-state current (up to 10(-3) A), high mobility and on-off ratio. An organic light emitting diode (OLED) driving circuit was constructed based on the printed TFTs, which exhibited high on-off ratio up to 10(4) and output current up to 3.5 × 10(-4) A at V(scan) = -4.5 V and Vdd = 0.8 V. A single OLED was switched on with the driving circuit, showing the potential as backplanes for active matrix OLED applications.

  20. Large area ITO-free flexible white OLEDs with Orgacon PEDOT:PSS and printed metal shunting lines

    NASA Astrophysics Data System (ADS)

    Harkema, Stephan; Mennema, Sibe; Barink, Marco; Rooms, Harmen; Wilson, Joanne S.; van Mol, Ton; Bollen, Dirk

    2009-08-01

    We demonstrate the feasibility of white organic light-emitting diodes that exclude the transparent conductor indium-tinoxide. Instead, a highly conductive OrgaconTM PEDOT:PSS material in combination with a metal support structure is used as transparent anode and hole-injection layer. The PEDOT:PSS exhibits a conductivity of 460+/-20 S/cm and a work function of 5.35+/-0.05 eV. On ITO-free OLEDs on glass with an active area of ~6 cm2 the inclusion of 120 nm thick printed metal lines reduces the variation in brightness from 35% to 20%. The ITO-free concept based on PEDOT:PSS with printed metal structures is scaled up to large flexible OLEDs with a size of 150 cm2 on a heat-stabilized Teonex® Polyethylene Naphtalate foil. The voltage distribution across the various electrodes was verified by a finite element model, allowing a prediction of the OLED brightness and homogeneity over large areas.

  1. Accurate prediction of emission energies with TD-DFT methods for platinum and iridium OLED materials.

    PubMed

    Morello, Glenn R

    2017-06-01

    Accurate prediction of triplet excitation energies for transition metal complexes has proven to be a difficult task when confronted with a variety of metal centers and ligand types. Specifically, phosphorescent transition metal light emitters, typically based on iridium or platinum, often give calculated results of varying accuracy when compared to experimentally determined T1 emission values. Developing a computational protocol for reliably calculating OLED emission energies will allow for the prediction of a complex's color prior to synthesis, saving time and resources in the laboratory. A comprehensive investigation into the dependence of the DFT functional, basis set, and solvent model is presented here, with the aim of identifying an accurate method while remaining computationally cost-effective. A protocol that uses TD-DFT excitation energies on ground-state geometries was used to predict triplet emission values of 34 experimentally characterized complexes, using a combination of gas phase B3LYP/LANL2dz for optimization and B3LYP/CEP-31G/PCM(THF) for excitation energies. Results show excellent correlation with experimental emission values of iridium and platinum complexes for a wide range of emission energies. The set of complexes tested includes neutral and charged complexes, as well as a variety of different ligand types.

  2. Supramolecular assembly of metal-ligand chromophores for sensing and phosphorescent OLED applications.

    PubMed

    Wong, Keith Man-Chung; Chan, Maggie Mei-Yee; Yam, Vivian Wing-Wah

    2014-08-20

    The exploration of phosphorescent materials based on transition metal-ligand chromophoric complexes represents an important area of research in molecular materials. The knowledge and fundamental understanding of their photophysical properties offer a possible fine-tuning of their electronic absorption and luminescence properties. The strong propensity of d(8) transition metal compounds to form non-covalent metal···metal interactions facilitates supramolecular assembly and the formation of supramolecular nanostructures with interesting photophysical properties. The introduction of supramolecular assembly with hierarchical complexity involving non-covalent interactions could lead to research dimensions of unlimited possibilities and opportunities. This article briefly summarizes the latest progress on the use of d(8) metal-ligand chromophores as chemosensors, as exemplified by alkynylplatinum(II) complexes with emphasis on supramolecular assembly involving non-covalent interactions, and the recent advances in the utilization of d(8) metal-ligand phosphors, as exemplified by alkynylgold(III) system, for the exploration and development of phosphorescent OLEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fluorine effects in new indenofluorenedione derivatives for electron transporting layer in OLED devices.

    PubMed

    Lee, Jaehyun; Kim, Beomjin; Park, Youngil; Kim, Seungho; Park, Jongwook

    2014-08-01

    New three indenofluorenedione derivatives were synthesized and proposed for electron transporting layer (ETL). Three compounds are indeno[1,2-b]fluorene-6,12-dione (IF-dione), 2,8-Difluoro-indeno[1,2-b]fluorene-6,12-dione (Mono-F-lF-dione), and 1,2,3,7,8,9-Hexafluoro-indeno[1,2- b]fluorene-6,12-dione (Tri-F-IF-dione). UV-visible (UV-Vis) absorption of three compounds in THF solution state showed different absorption maximum values as follows: 292, 318 and 334 nm (IF-dione), 289, 314 and 329 nm (Mono-F-IF-dione), 285, 319 and 334 nm (Tri-F-IF-dione). Three compounds were inserted between emitting layer (EML) and cathode electrode as an ETL in OLED device: ITO/2-TNATA (60 nm)/NPB (15 nm)/Alq3 (30 nm)/synthesized compounds (30 nm)/LiF (1 nm)/Al (200 nm). I-V characteristics of three devices were investigated at 20 mA/cm2. Operating voltages of three compounds were 7.06 V (IF-dione), 6.42 V (MonoF-IF-dione), 5.36 V (TriF-IF-dione), respectively.

  4. Synthesis and characterization of germane/stannane-capped polysiloles for the fabrication of luminescent OLED.

    PubMed

    Kim, Myoung-Hee; Woo, Hee-Gweon; Kim, Whan Gi; Cho, Myong-Shik

    2009-12-01

    Dehydropolymerization (with various inorganic hydrides) and subsequent germane/stannane-capping (with Me2GeHCI and Ph2SnHCI) of 1,1-dihydrotetraphenylsilole (1) give electroluminescent germane/stannane-capped polysiloles (2) in high yield. The polymerization yield and molecular weight with Selectride increase in the order L-Selectride < N-Selectride < K-Selectride. The molecular weights increase in the order Red-Al < K-Selectride < Super Hydride. The germane/stannane-capped polysiloles 2 emit at 521 nm and are electroluminescent at 522 nm. The fluorescence quantum yield of 2 in toluene is (1.66 +/- 0.26) x 10(-2). The emission color is green and the maximum brightness of the device is 2,800 cd/m2 with a luminous efficiency of 0.68 lm/W. The type of end group exhibited no appreciable effect on the luminescent properties of polysilole backbone. Thus, the germane/stannane-capped polysiloles are found to be a good material for OLED fabrication.

  5. Convenient synthesis and characterization of silane-capped polysiloles for the fabrication of luminescent OLED.

    PubMed

    Kim, Myoung-Hee; Kim, So-Yeun; Kim, Bo-Hye; Woo, Hee-Gweon; Park, Sook-Hyun; Kim, You-Jeong

    2008-09-01

    Catalytic dehydropolymerization and subsequent silane-capping with R2SiHCI (R = Ph, Me) of 1,1-dihydrotetraphenylsilole (1) using various inorganic hydrides produces electroluminescent silane-capped polysiloles (2) in high yield. The polymerization yield and molecular weight increase in the order LiB[CH(CH3)C2H5]3H < NaB[CH(CH3)C2H5]3H < KB[CH(CH3)C2H5]3H. The molecular weights increase in the order Na[H2Al(OCH2CH2OCH3)2] < KB[CH(CH3)C2H5]3H < LiB(C2H5)3H. The silane-capped polysiloles 2 emit at 521 nm and are electroluminescent at 522 nm. The fluorescence quantum yield of 2 in toluene is (1.67 +/- 0.31) x 10(-2). The emission color is green and the maximum brightness of the device is 2900 cd/m2 with a luminous efficiency of 0.69 lm/W. The substituent type of silyl end group showed no appreciable effect on the luminescent properties of polysilole backbone. Thus, the silane-capped polysiloles are found to be a good material for OLED fabrication. A possible mechanism for the formation of 2 was suggested.

  6. Thermal Evaporation versus Spin-Coating: Electrical Performance in Columnar Liquid Crystal OLEDs.

    PubMed

    Eccher, Juliana; Zajaczkowski, Wojciech; Faria, Gregório C; Bock, Harald; von Seggern, Heinz; Pisula, Wojciech; Bechtold, Ivan H

    2015-08-05

    The electrical responses of a columnar liquid crystal (a diimidodiester derivative of benzo[ghi]perylene) deposited either by spin-coating or by thermal evaporation into a typical OLED device are compared. For the spin-coated film, homeotropic alignment was induced by thermal annealing, which enhanced the charge carrier mobility significantly. For the evaporated films, homeotropic alignment could not be obtained by annealing. However, a degree of rectification higher than 3 orders of magnitude was achieved, even without annealing, with an electrical response similar to the response of the aligned spin-coated film. A trap-limited space-charge-limited current model was used to extract the charge carrier mobility directly from the current-voltage curves. Grazing incidence wide-angle X-ray scattering confirmed the homeotropic alignment of the annealed spin-coated film, whereas the columns are mostly oriented parallel to the surface in the evaporated case. In a field-effect transistor with bottom-gate bottom-contact geometry, the evaporated film exhibited a typical behavior of an n-type transistor. The degree of intermolecular order is thereby strongly dependent on the deposition method where vacuum deposition leads to a higher order. This higher order, however, impedes reorientation by annealing of the evaporated film but leads to improved charge transport between the electrodes even without homeotropic alignment of columnar liquid crystal.

  7. Degradation of HTL layers during device operation in PhOLEDs

    NASA Astrophysics Data System (ADS)

    Sivasubramaniam, Varatharajan; Brodkorb, Florian; Hanning, Stephanie; Buttler, Oliver; Loebl, Hans Peter; van Elsbergen, Volker; Boerner, Herbert; Scherf, Ullrich; Kreyenschmidt, Martin

    2009-11-01

    Different analytical tools and methodologies are currently employed to determine degradation products of organic blue light emitting devices in order to identify the failure mechanisms which determine the lifetime of these devices. This article provides a deeper understanding of degradation mechanisms of organic light emitting diodes (OLEDs) during device operation. Degradation products of blue emitting devices containing 8% of the phosphorescent emitter iridium(III)bis(4,6-difluorophenyl)-pyridinato-N,C 2' picolinate (FIrpic) in a matrix containing bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminium (BAlq) as electron transport layer (ETL), 4,4',4″-tri( N-carbazolyl)triphenylamine (TCTA) and N, N'-diphenyl- N, N'-bis(1-naphthyl)-1,1'-biphenyl-4,4″-diamine (α-NPD) were investigated using laser desorption ionization (LDI) coupled with a time of flight mass spectrometry (TOF/MS). Especially chemical degradation pathways of the hole transport materials TCTA and α-NPD were investigated. The comparison of experimental data of unstressed and stressed device revealed that new reaction products are formed during the device operation. The linkage of TCTA fragments to the α-NPD core in an interfacial reaction as well as a dimerization of TCTA itself was observed. Ten new reaction products could be characterized via LDI-TOF-MS. Some of these compounds might possess a negative influence on the drop of efficiency and lifetime of blue light emitting devices based on FIrpic.

  8. Tunable white light emission in Parallel Tandem OLEDs made with silver metal as interlayer

    NASA Astrophysics Data System (ADS)

    Oliva, Jorge; Papadimitratos, Alexios; Zakhidov, Anvar; UT Dallas Team

    Parallel tandem organic light emitting diodes (OLEDs) which consisted in a top and bottom subunits, and joined with a thin layer of silver (interlayer) were fabricated. In this parallel tandem architecture the Ag metal is an active common anode, which permitted to inject holes into top and bottom subunits. Both subunits of the tandem can thus be connected functionally in a new geometry and addressed separately. Those Tandems had a yellow emitter (a mixture of MEH-PPV and TFB polymers) in the bottom subunit and a blue emitting molecule in the top subunit. The simultaneous combination of the emitted yellow and blue light when both subunits are operating produced white light. We could tune the white light from cool (CIE: 0.33, 0.25) to warm (CIE: 0.38, 0.39) by changing the intensity of the yellow light, that in turn depends on the ratio of MEH-PPV/TFB mixture used to make the emitting layer in the bottom subunit. We also compared the performance of the parallel tandem with these in series and we found additional advantages of the parallel architecture over the configuration for the series tandems such as: tunable chromaticity, lower turn on voltage (4V compared to 7V in the in-series tandem) and higher brightness. The best CIE coordinate we obtained for white light was (0.35, 0.35) which is near the ideal coordinate of (0.33,0.33).

  9. OLED-based DNA biochip for Campylobacter spp. detection in poultry meat samples.

    PubMed

    Manzano, Marisa; Cecchini, Francesca; Fontanot, Marco; Iacumin, Lucilla; Comi, Giuseppe; Melpignano, Patrizia

    2015-04-15

    Integrated biochips are the ideal solution for producing portable diagnostic systems that uncouple diagnosis from centralized laboratories. These portable devices exploit a multi-disciplinary approach, are cost effective and have several advantages including broader accessibility, high sensitivity, quick test results and ease of use. The application of such a device in food safety is considered in this paper. Fluorescence detection of a specific biological probe excited by an optical source is one of the most commonly used methods for quantitative analysis on biochips. In this study, we designed and characterized a miniaturized, highly-sensitive DNA biochip based on a deep-blue organic light-emitting diode. The molecular design of the diode was optimized to excite a fluorophore-conjugated DNA probe and tested using real meat samples to obtain a high sensitivity and specificity against one of the most common poultry meat contaminants: Campylobacter spp. Real samples were analyzed also by classical plate methods and molecular methods to validate the results obtained by the new DNA-biochip. The high sensitivity obtained by the OLED based biochip (0.37ng/μl) and the short time required for the results (about 24h) indicate the usefulness of the system. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. [Improved color purity of green OLED device based on Au thin film].

    PubMed

    Zhang, Yan-Fei; Zhao, Su-Ling; Xu, Zheng

    2014-04-01

    Au was used as anode in some kind of organic electroluminescent devices. Sometimes transparent Au electrodes are required, which means that the thickness of Au electrode should be as thin as possible. Therefore, two metals together forming an electrode become a choice. In the present paper, translucent Au/Al layer was inserted to anode side, and OLED device with the structure of ITO/Al (16 nm)/Au (10 nm)/TPD (30 nm)/AlQ (30 nm)/LiF (0.5 nm)/Al was prepared. There is a spectral narrowing phenomenon on the device ITO/TPD (30 nm)/AlQ (30 nm)/LiF (0. 5 nm)/Al, and through analysis and experiment it was found that this phenomenon comes from selective permeability to light of Au thin film rather than the microcavity effect. The device maintains wide viewing angle, without the angular dependence. And the color purity of device with Au thin film is improved.

  11. Photophysical properties and OLED applications of phosphorescent platinum(II) Schiff base complexes.

    PubMed

    Che, Chi-Ming; Kwok, Chi-Chung; Lai, Siu-Wai; Rausch, Andreas F; Finkenzeller, Walter J; Zhu, Nianyong; Yersin, Hartmut

    2010-01-04

    The syntheses, crystal structures, and detailed investigations of the photophysical properties of phosphorescent platinum(II) Schiff base complexes are presented. All of these complexes exhibit intense absorption bands with lambda(max) in the range 417-546 nm, which are assigned to states of metal-to-ligand charge-transfer ((1)MLCT) (1)[Pt(5d)-->pi*(Schiff base)] character mixed with (1)[lone pair(phenoxide)-->pi*(imine)] charge-transfer character. The platinum(II) Schiff base complexes are thermally stable, with decomposition temperatures up to 495 degrees C, and show emission lambda(max) at 541-649 nm in acetonitrile, with emission quantum yields up to 0.27. Measurements of the emission decay times in the temperature range from 130 to 1.5 K give total zero-field splitting parameters of the emitting triplet state of 14-28 cm(-1). High-performance yellow to red organic light-emitting devices (OLEDs) using these platinum(II) Schiff base complexes have been fabricated with the best efficiency up to 31 cd A(-1) and a device lifetime up to 77 000 h at 500 cd m(-2).

  12. Modifying the organic/electrode interface in Organic Solar Cells (OSCs) and improving the efficiency of solution-processed phosphorescent Organic Light-Emitting Diodes (OLEDs)

    SciTech Connect

    Xiao, Teng

    2012-01-01

    Organic semiconductors devices, such as, organic solar cells (OSCs), organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs) have drawn increasing interest in recent decades. As organic materials are flexible, light weight, and potentially low-cost, organic semiconductor devices are considered to be an alternative to their inorganic counterparts. This dissertation will focus mainly on OSCs and OLEDs. As a clean and renewable energy source, the development of OSCs is very promising. Cells with 9.2% power conversion efficiency (PCE) were reported this year, compared to < 8% two years ago. OSCs belong to the so-called third generation solar cells and are still under development. While OLEDs are a more mature and better studied field, with commercial products already launched in the market, there are still several key issues: (1) the cost of OSCs/OLEDs is still high, largely due to the costly manufacturing processes; (2) the efficiency of OSCs/OLEDs needs to be improved; (3) the lifetime of OSCs/OLEDs is not sufficient compared to their inorganic counterparts; (4) the physics models of the behavior of the devices are not satisfactory. All these limitations invoke the demand for new organic materials, improved device architectures, low-cost fabrication methods, and better understanding of device physics. For OSCs, we attempted to improve the PCE by modifying the interlayer between active layer/metal. We found that ethylene glycol (EG) treated poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT: PSS) improves hole collection at the metal/polymer interface, furthermore it also affects the growth of the poly(3- hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends, making the phase segregation more favorable for charge collection. We then studied organic/inorganic tandem cells. We also investigated the effect of a thin LiF layer on the hole-collection of copper phthalocyanine (CuPc)/C70-based small molecular OSCs. A

  13. MATERIALS DEGRADATION ANALYSIS AND DEVELOPMENT TO ENABLE ULTRA LOW COST, WEB-PROCESSED WHITE P-OLED FOR SSL

    SciTech Connect

    DR. DEVIN MACKENZIE

    2011-12-13

    Progress over Phase II of DE-FG02-07ER86293 'Materials Degradation Analysis and Development to Enable Ultra Low Cost, Web-Processed White P-OLED for SSL' was initially rapid in terms of device performance improvements. We exceeded our device luminance lifetime goals for printed flexible white OLEDs as laid out in our project proposal. Our Phase II performance target was to demonstrate >1500 hours luminance lifetime at 100 Cd/m2 from a printed flexible device. We now have R&D devices well in excess of 8000 hrs lifetime at 100 Cd/m2, tested in air. We also were able to produce devices which met the voltage target of >1500 hours below 15V operation. After completing the initial performance milestones, we went on to focus on color-related degradation issues which were cited as important to commercialization of the technology by our manufacturing partners. We also put additional focus on cathode work as the active material development that occurred over the STTR time period required an adaptation of the cathode from the original cathode formulations which were developed based on previous generation active layer materials. We were able to improve compatibility of the cathode with some of the newer generation active layer materials and improve device yield and voltage behavior. An additional objective of the initial Phase II was to further develop the underlying manufacturing technology and real-life product specifications. This is a key requirement that must be met to ensure eventual commercialization of this DOE-funded technology. The link between commercial investment for full commercialization and R&D efforts in OLED solid State Lighting is often a large one. Add-Vision's lower cost, printed OLED manufacturing approach is an attraction, but close engagement with manufacturing partners and addressing customer specifications is a very important link. Manufacturing technology encompasses development of moisture reduction encapsulation technology, improved cost

  14. An olive pollen protein with allergenic activity, Ole e 10, defines a novel family of carbohydrate-binding modules and is potentially implicated in pollen germination

    PubMed Central

    2005-01-01

    CBMs (carbohydrate-binding modules) are the most common non-catalytic modules associated with enzymes active in plant cell-wall hydrolysis. They have been frequently identified by amino acid sequence alignments, but only a few have been experimentally established to have a carbohydrate-binding activity. A small olive pollen protein, Ole e 10 (10 kDa), has been described as a major inducer of type I allergy in humans. In the present study, the ability of Ole e 10 to bind several polysaccharides has been analysed by affinity gel electrophoresis, which demonstrated that the protein bound 1,3-β-glucans preferentially. Analytical ultracentrifugation studies confirmed binding to laminarin, at a protein/ligand ratio of 1:1. The interaction of Ole e 10 with laminarin induced a conformational change in the protein, as detected by CD and fluorescence analyses, and an increase of 3.6 °C in the thermal denaturation temperature of Ole e 10 in the presence of the glycan. These results, and the absence of alignment of the sequence of Ole e 10 with that of any classified CBM, indicate that this pollen protein defines a novel family of CBMs, which we propose to name CBM43. Immunolocalization of Ole e 10 in mature and germinating pollen by transmission electron microscopy and confocal laser scanning microscopy demonstrated the co-localization of Ole e 10 and callose (1,3-β-glucan) in the growing pollen tube, suggesting a role for this protein in the metabolism of carbohydrates and in pollen tube wall re-formation during germination. PMID:15882149

  15. Role of the ubiquitin-selective CDC48UFD1/NPL4 chaperone (segregase) in ERAD of OLE1 and other substrates

    PubMed Central

    Braun, Sigurd; Matuschewski, Kai; Rape, Michael; Thoms, Sven; Jentsch, Stefan

    2002-01-01

    The OLE pathway of yeast regulates the abundance of the ER-bound enzyme Δ-9 fatty acid desaturase OLE1, thereby controlling unsaturated fatty acid pools and membrane fluidity. Previously, we showed that this pathway is exquisitely regulated by the ubiquitin/proteasome system. Activation of the pathway involves proteasomal processing of a membrane-bound transcription factor and the subsequent mobilization of the cleaved, ubiquitylated transcription factor from its partner molecule by CDC48UFD1/NPL4, a ubiquitin-selective chaperone-like enzyme. Here we report that the OLE1 protein itself is naturally short-lived and is degraded by ubiquitin/proteasome-dependent ER-associated degradation (ERAD). We found that CDC48UFD1/NPL4 plays a second role in the OLE pathway by mediating ERAD of OLE1. Intriguingly, other ERAD substrates also require CDC48UFD1/NPL4 for degradation, indicating that this enzyme is a novel, constitutive component of the ERAD machinery. We propose that CDC48UFD1/NPL4 functions as a segregase that liberates ubiquitylated proteins from non-modified partners. PMID:11847109

  16. Life test results of OLED-XL long-life devices for use in active matrix organic light emitting diode (AMOLED) displays for head mounted applications

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Ghosh, Amalkumar P.; Prache, Olivier

    2007-04-01

    eMagin Corporation has recently developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. AMOLED displays have been known to exhibit high levels of performance with regards to contrast, response time, uniformity, and viewing angle, but a lifetime improvement has been perceived to be essential for broadening the applications of OLED's in the military and in the commercial market. The new OLED-XL devices gave the promise of improvements in usable lifetime over 6X what the standard full color, white, and green devices could provide. The US Army's RDECOM CERDEC NVESD performed life tests on several standard and OLED-XL panels from eMagin under a Cooperative Research and Development Agreement (CRADA). Displays were tested at room temperature, utilizing eMagin's Design Reference Kit driver, allowing computer controlled optimization, brightness adjustment, and manual temperature compensation. The OLED Usable Lifetime Model, developed under a previous NVESD/eMagin SPIE paper presented at DSS 2005, has been adjusted based on the findings of these tests. The result is a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be needed.

  17. [Evaluation of the quality of Anales Españoles de Pediatría versus Medicina Clínica].

    PubMed

    Bonillo Perales, A

    2002-08-01

    To compare the scientific methodology and quality of articles published in Anales Españoles de Pediatría and Medicina Clínica. A stratified and randomized selection of 40 original articles published in 2001 in Anales Españoles de Pediatría and Medicina Clínica was made. Methodological errors in the critical analysis of original articles (21 items), epidemiological design, sample size, statistical complexity and levels of scientific evidence in both journals were compared using the chi-squared and/or Student's t-test. No differences were found between Anales Españoles de Pediatría and Medicina Clínica in the critical evaluation of original articles (p > 0.2). In original articles published in Anales Españoles de Pediatría, the designs were of lower scientific evidence (a lower proportion of clinical trials, cohort and case-control studies) (17.5 vs 42.5 %, p 0.05), sample sizes were smaller (p 0.003) and there was less statistical complexity in the results section (p 0.03). To improve the scientific quality of Anales Españoles de Pediatría, improved study designs, larger sample sizes and greater statistical complexity are required in its articles.

  18. Microwave assisted transformation of N,N-diphenylamine as precursors of organic light emitting diodes (OLED)

    SciTech Connect

    Jefri,; Wahyuningrum, Deana

    2015-09-30

    In this research, study on the transformation of N,N-diphenylamine (DPA) using iodine (I2) utilizing solid state Microwave Assisted Organic Synthesis (MAOS) method has been carried out. The reaction was performed by variations of three parameters namely the mole of reagents, the amount and type of solid support (alumina/Al2O3), and the reaction conditions. Experimental results showed that neutral-alumina was a better solid support than basic-alumina. The optimum temperature for the reaction was approximately at 125-133 °C with reaction time of 15 minutes and microwave reactor power at 500-600 W. The separation of the yellowish green product solution with preparative Thin Layer Chromatography (TLC) method using n-hexane:ethyl acetate = 4:1 (v/v) as eluent yielded two fractions (I and II) and both fractions can undergo fluorescence under 365 nm UV light. Based on the LC chromatogram with methanol:water = 95:5 (v/v) as eluent and its corresponding mass spectra (ESI+), fraction I contained three compounds, which were tetracarbazole A, triphenylamine, and impurities in the form of plasticizer such as bis(2-ethylhexyl) phthalate. Fraction II also contained three compounds, which were tetracarbazole C, tetraphenylhydrazine, and plasticizer such as bis(2-ethylhexyl) phthalate. Both FT-IR (KBr disks) and NMR (500 MHz, CDCl{sub 3}) spectra of fraction I and II confirmed the aromatic amine groups in those compounds. The observed fluorescence colors of fraction I and II were violet and violet-blue, respectively. Based on their structures and fluorescence characters, the compounds in fraction I and II have the potential to be used as Organic Light Emitting Diode (OLED) compound precursors.

  19. Microwave assisted transformation of N,N-diphenylamine as precursors of organic light emitting diodes (OLED)

    NASA Astrophysics Data System (ADS)

    Jefri, Wahyuningrum, Deana

    2015-09-01

    In this research, study on the transformation of N,N-diphenylamine (DPA) using iodine (I2) utilizing solid state Microwave Assisted Organic Synthesis (MAOS) method has been carried out. The reaction was performed by variations of three parameters namely the mole of reagents, the amount and type of solid support (alumina/Al2O3), and the reaction conditions. Experimental results showed that neutral-alumina was a better solid support than basic-alumina. The optimum temperature for the reaction was approximately at 125-133 °C with reaction time of 15 minutes and microwave reactor power at 500-600 W. The separation of the yellowish green product solution with preparative Thin Layer Chromatography (TLC) method using n-hexane:ethyl acetate = 4:1 (v/v) as eluent yielded two fractions (I and II) and both fractions can undergo fluorescence under 365 nm UV light. Based on the LC chromatogram with methanol:water = 95:5 (v/v) as eluent and its corresponding mass spectra (ESI+), fraction I contained three compounds, which were tetracarbazole A, triphenylamine, and impurities in the form of plasticizer such as bis(2-ethylhexyl) phthalate. Fraction II also contained three compounds, which were tetracarbazole C, tetraphenylhydrazine, and plasticizer such as bis(2-ethylhexyl) phthalate. Both FT-IR (KBr disks) and NMR (500 MHz, CDCl3) spectra of fraction I and II confirmed the aromatic amine groups in those compounds. The observed fluorescence colors of fraction I and II were violet and violet-blue, respectively. Based on their structures and fluorescence characters, the compounds in fraction I and II have the potential to be used as Organic Light Emitting Diode (OLED) compound precursors.

  20. [Highly Efficient Bilayer-Structure Yellow-Green OLED with MADN Hole-Transport Layer and the Impedance Spectroscopy Analysis].

    PubMed

    Zhang, Xiao-wen; Mo, Bing-jie; Liu, Li-ming; Wang, Hong-hang; Chen, Er-wei; Xu, Ji-wen; Wang, Hua

    2015-12-01

    Abstract Highly efficient bilayer-structure yellow-green organic light-emitting device (OLED) has been demonstrated based on MADN as hole-transport layer (HTL) and host-guest coped system of [Alq₃: 0.7 Wt% rubrene] as emitting and electron-trans- port layer. The device gives yellow-green emission through incomplete energy transfer from the host of Alq₃ to the guest of ru- brene. An electroluminescent peak of 560 nm, 1931 CIE color coordinates of (0.46, 0.52) and a maximum current efficiency of 7.63 cd · A⁻¹ (which has been enhanced by 30% in comparison with the counterpart having conventional NPB HTL) are ob- served. The hole-transporting characteristics of MADN and NPB have been systematically investigated by constructing hole-only devices and employing impedance spectroscopy analysis. Our results indicate that MADN can be served as an effective hole-trans- port material and its hole-transporting ability is slightly inferior to NPB. This overcomes the shortcoming of hole transporting more quickly than electron in OLED and improves carrier balance in the emitting layer. Consequently, the device current efficien- cy is promoted. In addition, the current efficiency of bilayer-structure OLED with MADN as HTL is comparable to that of conv- entinol trilayer-structure device with MADN as HTL and Alq₃ as electron-transport layer. This indicates that the simplified bi- layer-structure device can be achieved without sacrificing current efficiency. The emitting layer of [Alq: 0.7 Wt% rubrene possesses superior elecron-transporting ability.

  1. Synthesis, structure, properties, and application of a carbazole-based diaza[7]helicene in a deep-blue-emitting OLED.

    PubMed

    Shi, Longqiang; Liu, Zhi; Dong, Guifang; Duan, Lian; Qiu, Yong; Jia, Jiong; Guo, Wei; Zhao, Dan; Cui, Deliang; Tao, Xutang

    2012-06-25

    A carbazole-based diaza[7]helicene, 2,12-dihexyl-2,12-diaza[7]helicene (1), was synthesized by a photochemical synthesis and its use as a deep-blue dopant emitter in an organic light-emitting diode (OLED) was examined. Compound 1 exhibited good solubility and excellent thermal stability with a high decomposition temperature (T(d)=372.1 °C) and a high glass-transition temperature (T(g), up to 203.0 °C). Single-crystal structural analysis of the crystalline clathrate (1)(2)⋅cyclohexane along with a theoretical investigation revealed a non-planar-fused structure of compound 1, which prevented the close-packing of molecules in the solid state and kept the molecule in a good amorphous state, which allowed the optimization of the properties of the OLED. A device with a structure of ITO/NPB (50 nm)/CBP:5 % 1 (30 nm)/BCP (20 nm)/Mg:Ag (100 nm)/Ag (50 nm) showed saturated blue light with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.10); the maximum luminance efficiency and brightness were 0.22 cd A(-1) (0.09 Lm W(-1)) and 2365 cd m(-2), respectively. This new class of helicenes, based on carbazole frameworks, not only opens new possibilities for utilizing helicene derivatives in deep-blue-emitting OLEDs but may also have potential applications in many other fields, such as molecular recognition and organic nonlinear optical materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays

    SciTech Connect

    McCarthy, M. A.; Liu, B.; Donoghue, E. P.; Kravchenko, Ivan I; Kim, D. Y.; So, Franky; Rinzler, A. G.

    2011-01-01

    Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

  3. A planar, chip-based, dual-beam refractometer using an integrated organic light-emitting diode (OLED) light source and organic photovoltaic (OPV) detectors.

    PubMed

    Ratcliff, Erin L; Veneman, P Alex; Simmonds, Adam; Zacher, Brian; Huebner, Daniel; Saavedra, S Scott; Armstrong, Neal R

    2010-04-01

    We present a simple chip-based refractometer with a central organic light-emitting diode (OLED) light source and two opposed organic photovoltaic (OPV) detectors on an internal reflection element (IRE) substrate, creating a true dual-beam sensor platform. For first-generation platforms, we demonstrate the use of a single heterojunction OLED based on electroluminescence from an Alq(3)/TPD heterojunction (tris-(8-hydroxyquinoline)aluminum/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine) and light detection with planar heterojunction pentacene/C(60) OPVs. The sensor utilizes the considerable fraction of emitted light from conventional thin-film OLEDs that is coupled into guided modes in the IRE, instead of into the forward (display) direction. A ray-optics description is used to describe light throughput and efficiency-limiting factors for light coupling from the OLED into the substrate modes, light traversing through the IRE substrate, and light coupling into the OPV detectors. The arrangement of the OLED at the center of the chip provides for two sensing regions: a "sample" channel and a "reference" channel, with detection of light by independent OPV detectors. This configuration allows for normalization of the sensor response against fluctuations in OLED light output, stability, and local fluctuations (temperature) that might influence sensor response. The dual-beam configuration permits significantly enhanced sensitivity to refractive index changes, relative to single-beam protocols, and is easily integrated into a field-portable instrumentation package. Changes in refractive index (DeltaRI) between 10(-2) and 10(-3) RI units could be detected for single beam operation, with sensitivity increased to DeltaRI approximately 10(-4) RI units when the dual-beam configuration is employed.

  4. A Planar, Chip-Based, Dual-Beam Refractometer Using an Integrated Organic Light Emitting Diode (OLED) Light Source and Organic Photovoltaic (OPV) Detectors

    PubMed Central

    Ratcliff, Erin L.; Veneman, P. Alex; Simmonds, Adam; Zacher, Brian; Huebner, Daniel

    2010-01-01

    We present a simple chip-based refractometer with a central organic light emitting diode (OLED) light source and two opposed organic photovoltaic (OPV) detectors on an internal reflection element (IRE) substrate, creating a true dual-beam sensor platform. For first-generation platforms, we demonstrate the use of a single heterojunction OLED based on electroluminescence emission from an Alq3/TPD heterojunction (tris-(8-hydroxyquinoline)aluminum/N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine) and light detection with planar heterojunction pentacene/C60 OPVs. The sensor utilizes the considerable fraction of emitted light from conventional thin film OLEDs that is coupled into guided modes in the IRE instead of into the forward (display) direction. A ray-optics description is used to describe light throughput and efficiency-limiting factors for light coupling from the OLED into the substrate modes, light traversing through the IRE substrate, and light coupling into the OPV detectors. The arrangement of the OLED at the center of the chip provides for two sensing regions, a “sample” and “reference” channel, with detection of light by independent OPV detectors. This configuration allows for normalization of the sensor response against fluctuations in OLED light output, stability, and local fluctuations (temperature) which might influence sensor response. The dual beam configuration permits significantly enhanced sensitivity to refractive index changes relative to single-beam protocols, and is easily integrated into a field-portable instrumentation package. Changes in refractive index (ΔR.I.) between 10−2 and 10−3 R.I. units could be detected for single channel operation, with sensitivity increased to ΔR.I. ≈ 10−4 units when the dual beam configuration is employed. PMID:20218580

  5. [Analysis of the impact of Anales Españoles de Pediatría through the Science Citation Index from 1997-2000].

    PubMed

    García Río, F; Mayoralas Alises, S; Esparza Paz, P; González Pérez-Yarza, E

    2002-08-01

    To quantify the impact factor of Anales Españoles de Pediatría from 1997 until 2000 and to identify the journal's citation patterns and the topics with the greatest impact. SCISEARCH was used to locate citations of articles published in Anales Españoles de Pediatría between 1995 and 1999. The following data were collected for each article: year of publication, authors, journal, country of publication, language, specialty or specialties, institution(s), residence of the first author and topic. The impact factor was calculated as the ratio between citations received over 1 year by articles published in Anales Españoles de Pediatría in the two previous years and the total number of articles published by Anales Españoles de Pediatría over the 2 years under study. The impact factor of Anales Españoles de Pediatría was 0.052 in 1997, 0.080 in 1998, 0.101 in 1999, 0.089 in 2000 and 0.064 in 2001. Citations were found in a wide range of source journals. The greatest proportion (35.6 %) were found in Spanish medical journals. Citations were made mainly by Spanish authors (62.8 %) and self-citation was moderate (14.3 %). Topics related to neurology (16.9 % of the citations received), infectious diseases (16.2 %) and neonatology (14.8 %) had the greatest impact. The impact factor of Anales Españoles de Pediatria is modest, although higher than that of some other biomedical publications included in Journal Citation Reports.

  6. Efficient Layers of Emitting Ternary Lanthanide Complexes for Fabricating Red, Green, and Yellow OLEDs.

    PubMed

    Ahmed, Zubair; Iftikhar, Khalid

    2015-12-07

    A series of novel nona- and octacoordinate highly volatile and luminescent complexes, [Eu(hfaa)3(indazole)3] and [Ln(hfaa)3(indazole)2] (Ln = Tb, Dy, and Lu), were synthesized using a monoanionic bidentate hexafluoroacetylacetone (hfaa(-)) and a neutral monodentate indazole ligand. The X-ray diffraction analyses of their single-crystals indicate that the complexes are mononuclear. The Eu complex is nonacoordinate and has a distorted monocapped square antiprismatic structure whereas the terbium and dysprosium complexes are octacoordinate and possess a trigonal bicapped prism geometry. The indazole units are involved in π-π stacking interaction and N-H···F hydrogen bonding with the fluorine atoms of hfaa(-). The photophysical studies of indazole and the complexes show that the triplet states are at the appropriate positions and make ligand-to-metal energy transfer process efficient. A strong protective shield is provided by the coordination of three hfaa(-) moieties (which have low frequency C-F vibrational oscillators), and two/three ancillary indazole ligands around these metal ions ascribe higher quantum yields and longer radiative life times (ΦEu = 69% ± 10, 989 ± 1 μs, ΦTb = 33% ± 10, 546 ± 1 μs, and ΦDy = 2.5% ± 10, 13.6 ± 1 μs) to these novel compounds. The emission from europium, terbium, and dysprosium are, respectively, red, green, and yellow. Finally, these compounds were used, as emitting layers, to fabricate electroluminescent devices of their respective colors. The best devices are found with the following structure: ITO/CuPc (15 nm)/[Eu complex]:CBP or [Tb complex]:CBP or [Dy complex]:CBP (80 nm)/BCP (25 nm)/AlQ (30 nm)/LiF (1 nm)/Al (100 nm), which indicates an improved EL performance for the Eu device over the Eu devices reported in the literature. The ligand, indazole, is a good sensitizer for trivalent europium, terbium, and dysprosium ions. It together with hfaa(-) plays an important role in fabricating OLEDs, especially

  7. [Anales Españoles de Pediatría 2001. Bibliometric indicators of scientific quality].

    PubMed

    González de Dios, J

    2002-08-01

    BACKGROUND. One important objective of Anales Españoles de Pediatría (An Esp Pediatr) is to be included in Journal Citation Reports-Science Citation Index and the main step to achieve this is to increase the scientific quality of this Spanish journal. Bibliometric indicators are important tools used to determine the quality of scientific publications. A bibliometric study of all the original articles published in An Esp Pediatr in 2001 (n 76) was performed; bibliometric indicators were classified into quantitative and qualitative (statistical analyses and level of scientific evidence). The results were compared with the original articles published in the journal from 1994 to June 2000 (n 733) and with the original articles published in Pediatrics in 2001 (n 276). The differences found in An Esp Pediatr between the two study periods were the following in 2001: greater collaboration between epidemiologists and/or biostatisticians in the authorship of articles (19.7 %), increased complexity of statistical analyses (statistical accessibility > 7 in 25 %) and greater use of evidence-based methodological concepts (19.7 %). However, no improvement was found in the scientific evidence (evidence was good in only 1.4 % and average in 25.7 %). Other aspects of interest were a lower number of original articles (due to an increase in other types of articles, such as Letters to the Editor or Special Articles) and a greater percentage of articles on evidence-based medicine or articles using its methodology. The differences in bibliometric indicators of quality found between An Esp Pediatr and Pediatrics continued to be considerable: statistical accessibility, evidence-based methodological concepts and scientific evidence (for example, good evidence was 22 times more frequent in Pediatrics). The scientific quality of An Esp Pediatr improved in 2001 compared with that of previous years, but the differences found between this journal and the gold standard of Pediatrics are still

  8. Novel hole transporting materials based on 4-(9H-carbazol-9-yl)triphenylamine derivatives for OLEDs.

    PubMed

    Nguyen, Quynh Pham Bao; Baek, Sueng Ji; Kim, Mi Jin; Shin, Na Young; Kim, Gyeong Woo; Choe, Dong Cheol; Kwon, Jang Hyuk; Chai, Kyu Yun

    2014-09-10

    During the past few years, organic light emitting diodes (OLEDs) have been increasingly studied due to their emerging applicability. However, some of the properties of existing OLEDs could be improved, such as their overall efficiency and durability; these aspects have been addressed in the current study. A series of novel hole-transporting materials (HTMs) 3a-c based on 4-(9H-carbazol-9-yl)triphenylamine conjugated with different carbazole or triphenylamine derivatives have been readily synthesized by Suzuki coupling reactions. The resulting compounds showed good thermal stabilities with high glass transition temperatures between 148 and 165 °C. The introduction of HTMs 3b and 3c into the standard devices ITO/HATCN/NPB/HTMs 3 (indium tin oxide/dipyrazino(2,3-f:2',3'-h)quinoxaline 2,3,6,7,10,11-hexacarbonitrile/N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine/HTMs)/CBP (4,4'-Bis(N-carbazolyl)-1,1'-biphenyl): 5% Ir(ppy)3/Bphen/LiF/Al (tris[2-phenylpyridinato-C2,N]iridium(III)/4,7-diphenyl-1,10-phenanthroline/LiF/Al) resulted in significantly enhanced current, power, and external quantum efficiencies (EQE) as compared to the reference device without any layers of HTMs 3.

  9. Synthesis Al complex and investigating effect of doped ZnO nanoparticles in the electrical and optical efficiency of OLEDS

    NASA Astrophysics Data System (ADS)

    Shahedi, Zahra; Jafari, Mohammad Reza

    2017-01-01

    In this study, an organometallic complex based on aluminum ions is synthesized. And it is utilized as fluorescent material in the organic light-emitting diodes (OLEDs). The synthesized complex was characterized using XRD, UV-Vis, FT-IR as well as PL spectroscopy analyses. The energy levels of Al complex were determined by cyclic voltammetry measurements. Then, the effects of ZnO nanoparticles (NPs) of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS, on the electrical and optical performance of the organic light-emitting diodes have been investigated. For this purpose, two samples containing ITO/PEDOT:PSS/PVK/Alq3/PBD/Al with two different concentration and two samples containing ITO/PEDOT:PSS:ZnO/PVK/Alq3/PBD/Al with two different concentration were prepared. Then, hole transport, electron transport and emissive layers were deposited by the spin coating method and the cathode layer (Al) was deposited by the thermal evaporation method. The OLED simulation was also done by constructing the model and choosing appropriate parameters. Then, the experimental data were collected and the results interpreted both qualitatively and quantitatively. The results of the simulations were compared with experimental data of the J-V spectra. Comparing experimental data and simulation results showed that the electrical and optical efficiency of the samples with ZnO NPs is appreciably higher than the samples without ZnO NPs.

  10. Formation of blade and slot die coated small molecule multilayers for OLED applications studied theoretically and by XPS depth profiling

    SciTech Connect

    Peters, Katharina; Raupp, Sebastian Scharfer, Philip; Schabel, Wilhelm; Hummel, Helga; Bruns, Michael

    2016-06-15

    Slot die coaters especially designed for low material consumption and doctor blades were used to process small molecule solutions for organic light-emitting diodes (OLEDs). Optimum process parameters were developed for the large-scale coating techniques to generate stable single and multiple layers only a few nanometers thick. Achieving a multilayer architecture for solution-processed OLEDs is the most challenging step. X-ray photoelectron spectroscopy sputter depth profiling was performed to determine defined interfaces between coated organic layers. Commercially available small molecules NPB (N,N’-Di(1-naphthyl)-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine) and BAlq (Bis(8-hdroxy-2methylquinoline)-(4-phenylphenoxy)aluminum), originally developed for vacuum deposition, were used as hole, respectively electron transport material. Defined double-layers were processed with both scalable coating methods using the orthogonal solvent approach. The use of non-orthogonal solvents resulted in complete intermixing of the material. The results are explained by calculations of solubilities and simulating drying and diffusion kinetics of the small molecule solutions.

  11. Turbocharged molecular discovery of OLED emitters: from high-throughput quantum simulation to highly efficient TADF devices

    NASA Astrophysics Data System (ADS)

    Gómez-Bombarelli, Rafael; Aguilera-Iparraguirre, Jorge; Hirzel, Timothy D.; Ha, Dong-Gwang; Einzinger, Markus; Wu, Tony; Baldo, Marc A.; Aspuru-Guzik, Alán.

    2016-09-01

    Discovering new OLED emitters requires many experiments to synthesize candidates and test performance in devices. Large scale computer simulation can greatly speed this search process but the problem remains challenging enough that brute force application of massive computing power is not enough to successfully identify novel structures. We report a successful High Throughput Virtual Screening study that leveraged a range of methods to optimize the search process. The generation of candidate structures was constrained to contain combinatorial explosion. Simulations were tuned to the specific problem and calibrated with experimental results. Experimentalists and theorists actively collaborated such that experimental feedback was regularly utilized to update and shape the computational search. Supervised machine learning methods prioritized candidate structures prior to quantum chemistry simulation to prevent wasting compute on likely poor performers. With this combination of techniques, each multiplying the strength of the search, this effort managed to navigate an area of molecular space and identify hundreds of promising OLED candidate structures. An experimentally validated selection of this set shows emitters with external quantum efficiencies as high as 22%.

  12. Optimal scan strategy for mega-pixel and kilo-gray-level OLED-on-silicon microdisplay.

    PubMed

    Ji, Yuan; Ran, Feng; Ji, Weigui; Xu, Meihua; Chen, Zhangjing; Jiang, Yuxi; Shen, Weixin

    2012-06-10

    The digital pixel driving scheme makes the organic light-emitting diode (OLED) microdisplays more immune to the pixel luminance variations and simplifies the circuit architecture and design flow compared to the analog pixel driving scheme. Additionally, it is easily applied in full digital systems. However, the data bottleneck becomes a notable problem as the number of pixels and gray levels grow dramatically. This paper will discuss the digital driving ability to achieve kilogray-levels for megapixel displays. The optimal scan strategy is proposed for creating ultra high gray levels and increasing light efficiency and contrast ratio. Two correction schemes are discussed to improve the gray level linearity. A 1280×1024×3 OLED-on-silicon microdisplay, with 4096 gray levels, is designed based on the optimal scan strategy. The circuit driver is integrated in the silicon backplane chip in the 0.35 μm 3.3 V-6 V dual voltage one polysilicon layer, four metal layers (1P4M) complementary metal-oxide semiconductor (CMOS) process with custom top metal. The design aspects of the optimal scan controller are also discussed. The test results show the gray level linearity of the correction schemes for the optimal scan strategy is acceptable by the human eye.

  13. Formation of blade and slot die coated small molecule multilayers for OLED applications studied theoretically and by XPS depth profiling

    NASA Astrophysics Data System (ADS)

    Peters, Katharina; Raupp, Sebastian; Hummel, Helga; Bruns, Michael; Scharfer, Philip; Schabel, Wilhelm

    2016-06-01

    Slot die coaters especially designed for low material consumption and doctor blades were used to process small molecule solutions for organic light-emitting diodes (OLEDs). Optimum process parameters were developed for the large-scale coating techniques to generate stable single and multiple layers only a few nanometers thick. Achieving a multilayer architecture for solution-processed OLEDs is the most challenging step. X-ray photoelectron spectroscopy sputter depth profiling was performed to determine defined interfaces between coated organic layers. Commercially available small molecules NPB (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and BAlq (Bis(8-hdroxy-2methylquinoline)-(4-phenylphenoxy)aluminum), originally developed for vacuum deposition, were used as hole, respectively electron transport material. Defined double-layers were processed with both scalable coating methods using the orthogonal solvent approach. The use of non-orthogonal solvents resulted in complete intermixing of the material. The results are explained by calculations of solubilities and simulating drying and diffusion kinetics of the small molecule solutions.

  14. Intense deep blue exciplex electroluminescence from NPB/TPBi:PPh3O-based OLEDs and their intrinsic degradation mechanisms (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph; Hippola, Chamika; Danilovic, Dusan; Bhattacharjee, Ujjal; Petrich, Jacob W.; Shinar, Ruth

    2016-09-01

    We describe intense and efficient deep blue (430 - 440 nm) exciplex emission from NPB/TPBi:PPh3O OLEDs where the luminous efficiency approaches 4 Cd/A and the maximal brightness exceeds 22,000 Cd/m2. Time resolved PL measurements confirm the exciplex emission from NPB:TPBi, as studied earlier by Monkman and coworkers [Adv. Mater. 25, 1455 (2013)]. However, the inclusion of PPh3O improves the OLED performance significantly. The effect of PPh3O on the EL and PL will be discussed. The NPB/TPBi:PPh3O-based OLEDs were also studied by optically and electrically detected magnetic resonance (ODMR and EDMR, respectively). In particular, the amplitude of the negative (EL- and current-quenching) spin 1/2 resonance, previously attributed to enhanced formation of strongly EL-quenching positive bipolarons, increases as the OLEDs degrade in a dry nitrogen atmosphere. This degradation mechanism is discussed in relation to degradation induced by hot polarons that are energized by exciton annihilation.

  15. Pure white OLED based on an organic small molecule: 2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine

    NASA Astrophysics Data System (ADS)

    Liu, Jian

    2015-10-01

    2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine (DBIP) was synthesized. The single-crystal structure of DBIP was resolved. DBIP-based OLED was fabricated. The electroluminescence for the device corresponds to a pure white emission. In addition, thermal stability, UV-vis, photoluminescence and electrochemical behaviors of DBIP were investigated as well.

  16. Ole e 1, the major allergen from olive (Olea europaea L.) pollen, increases its expression and is released to the culture medium during in vitro germination.

    PubMed

    de Dios Alché, Juan; M'rani-Alaoui, Mohamed; Castro, Antonio Jesús; Rodríguez-García, María Isabel

    2004-09-01

    Ole e 1 is a well-characterized allergenic protein from olive pollen. This paper examines its presence and that of its transcripts during in vitro pollen germination and pollen tube growth. A significant increase of the protein was detected after the emergence of the pollen tube, whereas part of the protein was released into the culture medium throughout pollen germination. A slight increase in the number of Ole e 1 transcripts was also detected prior to the described rise in the protein level. Within the pollen tube, the allergen was localized in the subapical region, mainly in the lumen of endoplasmic reticulum cisternae. Ole e 1 was also localized extracellularly in the vicinity of the pollen tube cell wall. These findings are discussed regarding the biological role attributed to the protein during pollen hydration and pollen tube growth and in terms of their importance for the understanding of the allergenic response in humans. On the basis of recent findings for the LAT52 protein in tomato, we propose that the homologous Ole e 1 protein might participate in a similar signal transduction pathway in olive, to control pregermination and pollen tube emergence and guidance.

  17. Cloning, purification, crystallization and preliminary X-ray diffraction of the OleC protein from Stenotrophomonas maltophilia involved in head-to-head hydrocarbon biosynthesis

    SciTech Connect

    Frias, JA; Goblirsch, BR; Wackett, LP; Wilmot, CM

    2010-08-28

    OleC, a biosynthetic enzyme involved in microbial hydrocarbon biosynthesis, has been crystallized. Synchrotron X-ray diffraction data have been collected to 3.4 A resolution. The crystals belonged to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 98.8, c = 141.0 A.

  18. The major olive pollen allergen (Ole e I) shows both gametophytic and sporophytic expression during anther development, and its synthesis and storage takes place in the RER.

    PubMed

    de Dios Alché, J; Castro, A J; Olmedilla, A; Fernández, M C; Rodríguez, R; Villalba, M; Rodríguez-García, M I

    1999-08-01

    The distribution of Ole e I (the major olive pollen allergen) and its transcripts was investigated in the anther from premeiotic stages until the dehiscent pollen stage. Crude protein extracts were analyzed by immunoblotting and probed with a monoclonal antibody to Ole e I. The protein, with three variants, was found to accumulate from the early microspore stage onwards. In addition to the previously reported localization of the protein, Ole e I has been immunolocalized for the first time within the pollen wall and in the tapetum. Reverse transcription-polymerase chain reaction analysis using specific oligonucleotides and RNA extracted from whole anthers revealed that the Ole e I gene is expressed from the late tetrad stage onwards. No expression was found in control tissues such as petals, roots or leaves. Light microscopy in situ hybridization on developing flower buds and dehiscent pollen confirmed the transcripts to be present in both the microspores and the sporophytic tissue (tapetum). Labeling was found primarily in the tapetum, reaching the highest concentration in the cytoplasm of the developing and mature pollen, once tapetum started to degenerate. In situ hybridization at the transmission electron microscope level showed the transcripts to accumulate on ribosomes of the rough endoplasmic reticulum. These studies, together with others carried out previously by us, indicated that both synthesis and storage of Ole e I take place in the endoplasmic reticulum, coincidentally with the conspicuous changes suffered by this membrane system during pollen development. This process is most likely controlled at the transcriptional level. The localization of the protein in the pollen ectexine bring new insights into the function of the allergen, which are discussed.

  19. Research of the penetration gas methods of measuring barrier property of OLED packaging materials by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wu, Qipeng; Li, Junjian; Wang, Chunyong; Fu, Zhaohui

    2016-10-01

    Measuring penetration rates of water vapor and oxygen though OLED packaging materials by mass spectrometry is a new method. Currently, the sampling of penetration gas is dynamic sampling method. The sensitivity of this method is magnitude of 10-4 g/m2day, which can not reach the ideal magnitude of 10-6 g/m2day. Static accumulation sampling method for improving sensitivity of measuring is present in this paper. Comparing with dynamic sampling method, the sensitivity of this sampling method has been improved 1-2 magnitudes. The devices of static accumulation sampling method have been designed. The experiments of measuring penetration rates of water vapor and oxygen through packaging materials have been done. The results and analysis of the experiments have been introduced.

  20. Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers.

    PubMed

    Katchman, Benjamin A; Smith, Joseph T; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O'Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S

    2016-07-04

    Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm(2). Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers.

  1. Systematic color tuning of a family of luminescent azole-based organoboron compounds suitable for OLED applications.

    PubMed

    Kiprof, Paul; Carlson, Jeffrey C; Anderson, Derrick R; Nemykin, Victor N

    2013-11-14

    A new tunable luminescent family of heterocyclic aromatic compounds containing boron has been prepared and characterized through NMR spectroscopy, mass spectrometry, absorption and fluorescence spectroscopy as well as structural study using single crystal X-ray crystallography. Spectroscopic properties of the new compounds were also studied using DFT and TDDFT computational models that showed very good agreement of the theoretical data with experimental results. Through introduction of auxochromic atoms such as sulfur and extension of the π system of the ligands it is possible to cover a large range of the visible spectrum. Activation and enhancement of the luminescence is achieved by condensation reactions that introduce the boron fragment forming stable, sublimable compounds suitable for OLED applications.

  2. Purification, amino acid sequence and immunological characterization of Ole e 6, a cysteine-enriched allergen from olive tree pollen.

    PubMed

    Batanero, E; Ledesma, A; Villalba, M; Rodríguez, R

    1997-06-30

    The Ole e 6 allergen from olive tree pollen has been isolated by combining gel permeation and reverse-phase chromatographies. It is a single and highly acidic (pI 4.2) polypeptide chain protein. Its NH2-terminal amino acid sequence has been determined by Edman degradation. Total RNA from the olive tree pollen was isolated, and a specific cDNA was amplified by the polymerase chain reaction using a degenerate oligonucleotide primer designed according to the NH2-terminal sequence of the protein. The nucleotide sequencing of the cDNA rendered an open reading frame encoding a 50 amino acid polypeptide chain, in which two sets of the sequential motif Cys-X3-Cys-X3-Cys are present. No sequence similarity has been found between this protein and other previously described polypeptides.

  3. Linear and star-shaped benzimidazolyl derivatives: syntheses, photophysical properties and use as highly efficient electron transport materials in OLEDs.

    PubMed

    White, Wade; Hudson, Zachary M; Feng, Xiaodong; Han, Sijin; Lu, Zheng-Hong; Wang, Suning

    2010-01-21

    Five benzimidazolyl functionalized linear and star-shaped molecules have been synthesized using Ullmann condensation methods. These molecules all possess deep LUMO energy levels and large HOMO-LUMO energy gaps ranging from 3.55 to 3.95 eV. All five compounds are fluorescent with emission in the UV region, and display high thermal and morphological stability. One of these star-shaped molecules, 2,4,5-tris(benzimidazolyl)-1,3,5-triazine, has been demonstrated to be a highly effective electron transport/hole blocking material in organic light emitting devices (OLEDs) with performance comparable to the commonly used electron transport material Alq(3) (q = 8-hydroxyquinolinate). In addition, metal ion titrations have established that these ligands show a distinct fluorescent response to the addition of Ag(I) or Zn(II) in solution.

  4. Immunoproteomic tools are used to identify masked allergens: Ole e 12, an allergenic isoflavone reductase from olive (Olea europaea) pollen.

    PubMed

    Castro, Lourdes; Crespo, Jesús F; Rodríguez, Julia; Rodríguez, Rosalía; Villalba, Mayte

    2015-12-01

    Proteins performing important biochemical activities in the olive tree (Olea europaea) pollen have been identified as allergens. One novel 37-kDa protein seems to be associated to the IgE-binding profile of a group of patients suffering allergy to peach and olive pollen. Three previously described olive pollen allergens exhibit very similar molecular mass. Our objective was to identify this allergen by using immunoproteomic approaches. After 2D-electrophoresis and mass spectrometry, peptide sequences from several IgE-binding spots, allowed identifying this new allergen, as well as cloning and DNA sequencing of the corresponding gene. The allergen, named Ole e 12, is a polymorphic isoflavone reductase-like protein of 308 amino acids showing 80% and 74% identity with birch and pear allergens, Bet v 6 and Pyr c 5, respectively. A prevalence of 33% in the selected population is in contrast to 4%-10% in groups of subjects suffering from pollinosis. Recombinant allergen was produced in Escherichia coli, and deeply characterised. Immunoblotting and ELISA detection as well as inhibition experiments were performed with polyclonal antisera and allergic patients' sera. The recombinant allergen retains the IgE reactivity of its natural counterpart. Close structural and immunological relationships between members of this protein family were supported by their IgG recognition in vegetable species. In summary, Ole e 12 is a minor olive pollen allergen, which gains relevance in patients allergic to peach with olive pollinosis. Proteomic approaches used to analyse this allergen provide useful tools to identify hidden allergens, relevant for several allergic populations and thus complete allergenic panels.

  5. Assessment of the Olea pollen and its major allergen Ole e 1 concentrations in the bioearosol of two biogeographical areas

    NASA Astrophysics Data System (ADS)

    Moreno-Grau, S.; Aira, M. J.; Elvira-Rendueles, B.; Fernández-González, M.; Fernández-González, D.; García-Sánchez, A.; Martínez-García, M. J.; Moreno, J. M.; Negral, L.; Vara, A.; Rodríguez-Rajo, F. J.

    2016-11-01

    The Olea pollen is currently an important allergy source. In some regions of Southern Spain, olive pollen is the main cause of allergic sensitization exceeding 40% of the sensitized individuals. Due to the scarce presence of olive trees in Northern Spain, limited to some cultivated fields in the South of the Galicia region where they also grow wild, only 8% of the sensitized individuals showed positive results for Olea pollen. The aim of the paper was to assess the behaviour pattern of the Olea pollen and its aeroallergens in the atmosphere, as this information could help us to improve the understanding and prevention of clinical symptoms. Airborne Olea pollen and Ole e 1 allergens were quantified in Cartagena (South-eastern Spain) and Ourense (North-western Spain). A volumetric pollen trap and a Burkard Cyclone sampler were used for pollen and allergen quantification. The Olea flowering took place in April or May in both biometeorological sampling areas. The higher concentrations were registered in the Southern area of Spain, for both pollen and Ole e 1, with values 8 times higher for pollen concentrations and 40 times higher for allergens. An alternate bearing pattern could be observed, characterized by years with high pollen values and low allergen concentrations and vice versa. Moreover, during some flowering seasons the allergen concentrations did not correspond to the atmospheric pollen values. Variations in weather conditions or Long Distance Transport (LDT) processes could explain the discordance. The back trajectory analysis shows that the most important contributions of pollen and allergens in the atmosphere are coincident with air masses passing through potential source areas. The exposure to olive pollen may not be synonym of antigen exposure.

  6. Crystal Structures of Xanthomonas campestris OleA Reveal Features That Promote Head-to-Head Condensation of Two Long-Chain Fatty Acids

    SciTech Connect

    Goblirsch, BR; Frias, JA; Wackett, LP; Wilmot, CM

    2012-05-22

    OleA is a thiolase superfamily enzyme that has been shown to catalyze the condensation of two long-chain fatty acylcoenzyme A (CoA) substrates. The enzyme is part of a larger gene cluster responsible for generating long-chain olefin products, a potential biofuel precursor. In thiolase superfamily enzymes, catalysis is achieved via a ping-pong mechanism. The first substrate forms a covalent intermediate with an active site cysteine that is followed by reaction with the second substrate. For OleA, this conjugation proceeds by a nondecarboxylative Claisen condensation. The OleA from Xanthomonas campestris has been crystallized and its structure determined, along with inhibitor-bound and xenon-derivatized structures, to improve our understanding of substrate positioning in the context of enzyme turnover. OleA is the first characterized thiolase superfamily member that has two long-chain alkyl substrates that need to be bound simultaneously and therefore uniquely requires an additional alkyl binding channel. The location of the fatty acid biosynthesis inhibitor, cerulenin, that possesses an alkyl chain length in the range of known OleA substrates, in conjunction with a single xenon binding site, leads to the putative assignment of this novel alkyl binding channel. Structural overlays between the OleA homologues, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase and the fatty acid biosynthesis enzyme FabH, allow assignment of the two remaining channels: one for the thioester-containing pantetheinate arm and the second for the alkyl group of one substrate. A short beta-hairpin region is ordered in only one of the crystal forms, and that may suggest open and closed states relevant for substrate binding. Cys143 is the conserved catalytic cysteine within the superfamily, and the site of alkylation by cerulenin. The alkylated structure suggests that a glutamic acid residue (Glu117 beta) likely promotes Claisen condensation by acting as the catalytic base. Unexpectedly, Glu117

  7. Crystal Structures of Xanthomonas campestris OleA Reveal Features That Promote Head-to-Head Condensation of Two Long-Chain Fatty Acids

    SciTech Connect

    Goblirsch, Brandon R.; Frias, Janice A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2012-10-25

    OleA is a thiolase superfamily enzyme that has been shown to catalyze the condensation of two long-chain fatty acyl-coenzyme A (CoA) substrates. The enzyme is part of a larger gene cluster responsible for generating long-chain olefin products, a potential biofuel precursor. In thiolase superfamily enzymes, catalysis is achieved via a ping-pong mechanism. The first substrate forms a covalent intermediate with an active site cysteine that is followed by reaction with the second substrate. For OleA, this conjugation proceeds by a nondecarboxylative Claisen condensation. The OleA from Xanthomonas campestris has been crystallized and its structure determined, along with inhibitor-bound and xenon-derivatized structures, to improve our understanding of substrate positioning in the context of enzyme turnover. OleA is the first characterized thiolase superfamily member that has two long-chain alkyl substrates that need to be bound simultaneously and therefore uniquely requires an additional alkyl binding channel. The location of the fatty acid biosynthesis inhibitor, cerulenin, that possesses an alkyl chain length in the range of known OleA substrates, in conjunction with a single xenon binding site, leads to the putative assignment of this novel alkyl binding channel. Structural overlays between the OleA homologues, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase and the fatty acid biosynthesis enzyme FabH, allow assignment of the two remaining channels: one for the thioester-containing pantetheinate arm and the second for the alkyl group of one substrate. A short {beta}-hairpin region is ordered in only one of the crystal forms, and that may suggest open and closed states relevant for substrate binding. Cys143 is the conserved catalytic cysteine within the superfamily, and the site of alkylation by cerulenin. The alkylated structure suggests that a glutamic acid residue (Glu117{beta}) likely promotes Claisen condensation by acting as the catalytic base. Unexpectedly

  8. Vibronic coupling to simulate the phosphorescence spectra of Ir(III)-based OLED systems: TD-DFT results meet experimental data.

    PubMed

    Belaidi, Houmam; Belaidi, Salah; Katan, Claudine; Latouche, Camille; Boucekkine, Abdou

    2016-11-01

    The electronic and optical properties of six iridium imidazolylidene complexes (1a, 1b, 2, 2b, 3, 3b) that are strong candidates for use in OLED systems were investigated theoretically. Computations using DFT and TD-DFT methods were performed to explain the observed optical properties of these complexes. Observed absorption bands were assigned and the lowest triplet excited states were computed. Whereas complexes 1a and 1b are nonemissive in solution, the simulated phosphorescence spectra of complexes 2, 2b, 3, and 3b were in good agreement with the observed spectra when the vibrational contributions to the electronic transitions were taken into account. The use of vibronic coupling allowed us to reproduce and explain the structured phosphorescence spectra of complexes 2 and 2b, as well as the absence of such structure from the spectra of complexes 3 and 3b. Graphical Abstract Successful simulation of the phosphorescence spectra of Ir(III)-based OLED xsystems.

  9. Enhancing light extraction efficiency in MDMO-PPV based OLEDs by incorporating SiO2-250 nm colloidal crystals

    NASA Astrophysics Data System (ADS)

    Salcedo-Reyes, J. C.; Vázquez, J.; Jiménez, L. C.; Méndez-Pinzón, H.

    2017-02-01

    In this work, an improvement in light extraction efficiency from MDMO-PPV based OLEDs by using colloidal crystals is demonstrated. The optimal SiO2 sphere diameter for the colloidal crystal was calculated by the Plane Wave Expansion Method (PWEM), taking into account the dispersion relation of the system formed by a face-centered cubic colloidal crystal (FCC) infiltrated within the luminescent polymer MDMO-PPV. The fabrication method of such a polymer layer with a photonic crystal beneath by spin coating was proved and patented. Therefore, devices with the structure ITO/PEDOT/MDMO-PPV+SiO2 colloidal crystal/Ag were elaborated. Compared with standard OLEDs containing a single MDMO-PPV luminescent layer, the external quantum efficiency of devices modified with a colloidal crystal matrix within the MDMO-PPV layer shows a significant increment, as evaluated from the optical power as a function of applied bias for both kinds of devices.

  10. Does giant surface potential modify the performance of Alq3-based OLED?: voltage shift and charge traps induced by light irradiation

    NASA Astrophysics Data System (ADS)

    Noguchi, Yutaka; Sato, Naoki; Tanaka, Yuya; Nakayama, Yasuo; Ishii, Hisao

    2008-08-01

    A giant surface potential (GSP) has been observed on a tris-(8-hydroxyquinolate) aluminum (Alq3) film deposited on a glass or a metal substrate under dark conditions. However, the effects of a GSP on the device properties of Alq3-based organic light-emitting diodes (OLEDs) has not been considered. In this paper, we report on the effects of ambient light during the fabrication of an Alq3-based OLED on the device properties by displacement current measurement. We found that the light irradiation significantly reduces the density of charge existing at the 4,4'-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl/Alq3 interface and results in the formation of charge traps in the Alq3 layer. Considering the similarities between the GSP and the interfacial charge, they can be attributed to the same origin; the orientaion polarization of Alq3 film.

  11. Comparing the acceptor promiscuity of a Rosa hybrida glucosyltransferase RhGT1 and an engineered microbial glucosyltransferase OleD(PSA) toward a small flavonoid library.

    PubMed

    Wang, Lu; Han, Weiqing; Xie, Chenying; Hou, Jingli; Fang, Qinghong; Gu, Jianchun; Wang, Peng George; Cheng, Jiansong

    2013-03-07

    Glycosylation is a widespread modification of plant secondary metabolites, and catalyzed by a superfamily of enzymes called UDP-glycosyltransferases (UGTs). UGTs are often involved in late biosynthetic steps and show broad substrate specificity or regioselectivity. In this study, the acceptor promiscuity of a Rosa hybrid UGT RhGT1 and an evolved microbial UGT OleD(PSA) toward a small flavonoid library was probed and compared. Interestingly, RhGT1 showed comparable acceptor promiscuity in comparison with OleD(PSA), though the acceptor binding pocket of the latter is much more open and large. This clearly indicates that stabilization of the acceptor position by suitable hydrophobic interactions is important for the specificity or regioselectivity determination as well as overall fit of the acceptor into a 'big enough' binding pocket. This also poses a challenge for structure-based UGT engineering to alter the glucosylation pattern of flavonoids. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Thermoluminescence and a new organic light-emitting diode (OLED) based on triplet-triplet fluorescence of the trimethylenemethane (TMM) biradical.

    PubMed

    Namai, Hayato; Ikeda, Hiroshi; Hoshi, Yosuke; Kato, Nobuyuki; Morishita, Yoshii; Mizuno, Kazuhiko

    2007-07-25

    The results of an investigation of the thermoluminescence (TL) and electroluminescence (EL) of arylated methylenecyclopropanes 1, systems whose photoinduced electron-transfer (PET) chemistry has been thoroughly studied, are described. In both the TL and EL experiments with 1, electronically excited triplet trimethylenemethane (TMM) biradicals (3)2** are generated by back electron transfer (charge recombination) of a TMM radical cation (hole) 2*+, formed by isomerization of the substrate radical cation (hole, 1*+). The application of this chemistry to the design of new organic light-emitting diodes (OLEDs) is described. The mechanistic features of this reaction system have the potential of overcoming significant problems (e.g., quantum efficiency, difficulty obtaining long wavelength emission, and device durability) normally associated with OLEDs that rely on the use of organic closed-shell hydrocarbons.

  13. Enhanced light out-coupling of OLEDs with low haze by inserting randomly dispersed nanopillar arrays formed by lateral phase separation of polymer blends.

    PubMed

    Lee, Cholho; Kim, Jang-Joo

    2013-11-25

    A simple and efficient method to fabricate light extraction layers is demonstrated by utilizing the phase separation of two polymer blends to enhance the light out-coupling efficiency of OLEDs with low haze. Polystyrene and poly(methyl methacrylate) dissolved in tetrahydrofuran are mixed and spin-coated over ITO-coated glass substrates. Nanopores and nanopillar arrays are formed through lateral phase separation of the polymer blend. The shape, size, and distribution of the patterns can be controlled through changes in the composition and thickness of the coated polymer blends. Phosphorescent OLEDs are fabricated using randomly dispersed nanopillar arrays as light extraction layers and they show a 24% enhancement in external quantum efficiency with a Lambertian emission pattern, no spectrum dependence on viewing angles, and only a small increment in the haze. With these advantages, this newly developed method can be adapted to be used for large-area, flexible substrates for lighting and display applications.

  14. High-Performance Blue OLEDs Based on Phenanthroimidazole Emitters via Substitutions at the C6- and C9-Positions for Improving Exciton Utilization.

    PubMed

    Liu, Bin; Yuan, Yi; He, Dan; Huang, De-Yue; Luo, Cheng-Yuan; Zhu, Ze-Lin; Lu, Feng; Tong, Qing-Xiao; Lee, Chun-Sing

    2016-08-16

    Donor-acceptor (D-A) molecular architecture has been shown to be an effective strategy for obtaining high-performance electroluminescent materials. In this work, two D-A molecules, Ph-BPA-BPI and Py-BPA-BPI, have been synthesized by attaching highly fluorescent phenanthrene or pyrene groups to the C6- and C9-positions of a locally excited-state emitting phenylamine-phenanthroimidazole moiety. Equipped with good physical and hybridized local and charge-transfer properties, both molecules show high performances as blue emitters in nondoped organic light-emitting devices (OLEDs). An OLED using Ph-BPA-BPI as the emitting layer exhibits deep-blue emission with CIE coordinates of (0.15, 0.08), and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.56 %, 3.60 cd A(-1) , and 3.66 lm W(-1) , respectively. On the other hand, a Py-BPA-BPI-based, sky-blue OLED delivers the best results among nondoped OLEDs with CIEy values of < 0.3 reported so far, for which a very low turn-on voltage of 2.15 V, CIE coordinates of (0.17, 0.29), and maximum CE, PE, and EQE values of 10.9 cd A(-1) , 10.5 lm W(-1) , and 5.64 %, were achieved, respectively. More importantly, both devices show little or even no efficiency roll-off and high singlet exciton-utilizing efficiencies of 36.2 % for Ph-BPA-BPI and 39.2 % for Py-BPA-BPI.

  15. Pure white OLED based on an organic small molecule: 2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine.

    PubMed

    Liu, Jian

    2015-10-05

    2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine (DBIP) was synthesized. The single-crystal structure of DBIP was resolved. DBIP-based OLED was fabricated. The electroluminescence for the device corresponds to a pure white emission. In addition, thermal stability, UV-vis, photoluminescence and electrochemical behaviors of DBIP were investigated as well. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Bifunctional star-burst amorphous molecular materials for OLEDs: achieving highly efficient solid-state luminescence and carrier transport induced by spontaneous molecular orientation.

    PubMed

    Kim, Jun Yun; Yasuda, Takuma; Yang, Yu Seok; Adachi, Chihaya

    2013-05-21

    Bifunctional star-burst amorphous molecular materials displaying both efficient solid-state luminescence and high hole-transport properties are developed in this study. A high external electroluminescence quantum efficiency up to 5.9% is attained in OLEDs employing the developed amorphous materials. It is revealed that the spontaneous horizontal orientation of these light-emitting molecules in their molecular-condensed states leads to a remarkable enhancement of the electroluminescence efficiencies and carrier-transport properties.

  17. Largely blue-shifted emission through minor structural modifications: molecular design, synthesis, aggregation-induced emission and deep-blue OLED application.

    PubMed

    Huang, Jing; Sun, Ning; Chen, Pengyu; Tang, Runli; Li, Qianqian; Ma, Dongge; Li, Zhen

    2014-02-28

    By simply introducing additional groups with different size and conjugation degree to the 2,2'-positions of BTPE, four BTPE derivatives are prepared which give blue or deep-blue EL emissions when used as emitters in non-doped OLEDs, as the result of the tuned dihedral angles of the biphenyl cores (up to ~89°), providing a new approach to design AIE luminogens with blue and deep-blue emissions.

  18. Low-fluence rate, long duration photodynamic therapy in glioma mouse model using organic light emitting diode (OLED).

    PubMed

    Guo, Han-Wen; Lin, Liang-Ting; Chen, Po-Hsiung; Ho, Meng-Huan; Huang, Wan-Ting; Lee, Yi-Jang; Chiou, Shih-Hwa; Hsieh, Yei-San; Dong, Chen-Yuan; Wang, Hsing-Wen

    2015-09-01

    The treatment of gliomas poses significant clinical challenges due to resistance to chemo and radiation therapy, and treatment side effects. Metronomic photodynamic therapy (mPDT), which involves long treatment time with low fluence rate and multiple or continuous photosensitizer administrations, has potential in treating gliomas without threatening the quality of life and has been demonstrated in rats and rabbits. mPDT in small animals such as mouse is not yet shown due to lack of lightweight illumination device for long periods of time. We presented low fluence rate (3mW/cm(2)) and long duration (3.7h) PDT treatment in a nude mouse model of human glioblastoma by using organic light emitting diode (OLED) with single dose of 5-aminolevulinic acid (ALA) administration as photosensitizer. Tumor volume was measured using bioluminescent imaging and the animal survival time was recorded. Additionally, we have performed limited PDT dosimetric measurements of PpIX fluorescence, tumor oxygenation and hemoglobin concentration in 3 PDT mice. For animals with similar pre- and immediate post-light tumor volume, the averaged total survival time of PDT mice is 40.5±9.2 days that are significantly longer than the control mice (26.0±2.0 days). The post-light survival time of PDT mice is 14.3±5.9 days that are marginally longer than the control group (8.0±0.0 days). In the dosimetric measurement, good maintenance of PpIX fluorescence in one PDT mouse has relatively improved survival time, compared with the other two PDT mice (i.e., 24 days versus 16 and 17 days). This pilot study demonstrated the feasibility of low-fluence rate and long treatment time of ALA-PDT using OLED without anesthetization of animals. The response of PDT treated animals with similar pre- and post-light tumor volume is encouraging to show a longer survival time than the controls. The dosimetric indices such as photosensitizer fluorescence and tissue oxygenation would help understand the possible treatment

  19. High efficiency and low roll-off green OLEDs with simple structure by utilizing thermally activated delayed fluorescence material as the universal host

    NASA Astrophysics Data System (ADS)

    Zhao, Bo; Miao, Yanqin; Wang, Zhongqiang; Wang, Kexiang; Wang, Hua; Hao, Yuying; Xu, Bingshe; Li, Wenlian

    2017-08-01

    We achieved high-efficiency and low-roll-off green fluorescent and phosphorescent organic light-emitting diodes (OLEDs) simultaneously by adopting the thermally activated delayed fluorescence material of bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone as the universal host. At a luminance of 1000 cd/m2, fluorescent OLEDs based on C545T get a current efficiency, power efficiency, and external quantum efficiency (EQE) of 31.8 cd/A, 25.0 lm/W, and 9.26%, respectively. This is almost the highest efficiency based on C545T at the luminance of 1000 cd/m2 to date. On the other hand, phosphorescent OLEDs with Ir(ppy)3 as the emitter realize a maximum current efficiency, power efficiency, and EQE of 64.3 cd/A, 62.4 lm/W, and 18.5%, respectively. More important, the EQE remains 17.8% at the representative luminance of 1000 cd/m2 and the roll-off ratio is just 3.78%. The transient photoluminescence decay measurement demonstrates that the up-conversion of host triplet excitons plays a key role in the high efficiency and low roll-off. More detailed discussions are also given.

  20. Highly efficient tandem OLED based on C60/rubrene: MoO3 as charge generation layer and LiF/Al as electron injection layer

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Wu, Xiaoming; Xiao, Zhihui; Gao, Jian; Zhang, Juan; Rui, Hongsong; Lin, Xin; Zhang, Nan; Hua, Yulin; Yin, Shougen

    2017-08-01

    Tandem organic light-emitting diodes (OLEDs) have received much attention in solid-state lighting due to their high current efficiency, long lifetime and excellent stability. The highly efficient blue fluorescent tandem OLEDs based on the charge generation layer (CGL) of C60/rubrene: MoO3 and the electron injection layer (EIL) of LiF/Al were fabricated. The ultra-thin Al layer in EIL was introduced to further increase electron injection from CGL to the emission unit. We found that the maximal current efficiency and power efficiency of optimal tandem device can reach to 43.1 cd/A and 15.1 lm/W, respectively, which are approximately 2.8 and 1.9 times compared with those of single-emissive-unit device. Moreover, compared with the traditional tandem device, the driving voltage of the optimal device is reduced by 6 V, and the turn-on voltage is reduced by 2.4 V. We analyzed the mechanism and characterization of these tandem devices. The effective charge separation and transport of C60/rubrene: MoO3, and excellent electron injection ability of ultra-thin Al layer are the main factors for the remarkable enhancement in both current efficiency and power efficiency of tandem OLEDs.

  1. Theoretical study and design of multifunctional phosphorescent platinum(II) complexes containing triarylboron moieties for efficient OLED emitters.

    PubMed

    Wu, Yong; Shan, Guo-Gang; Li, Hai-Bin; Wu, Shui-Xing; Ren, Xin-Yao; Geng, Yun; Su, Zhong-Min

    2015-01-28

    The geometries, electronic structures, photophysical properties and spin-orbit coupling (SOC) effects in the radiative process for the recently synthesized complexes (Bppy)Pt(acac) (1) and (BNppy)Pt(acac) (2) as well as the designed complexes 3-6 were investigated by DFT and TD-DFT calculations, to reveal the influences of the functional ligands on charge injection ability and phosphorescence efficiency of emitters. It is found that compared with electron acceptor complex 1, complexes 2-6 have lower ionization potentials and comparable high electronic affinities, which are suited for bipolar luminescent materials. The results also demonstrated that Bppy complexes 1, 5 and 6 have more (3)MLCT compositions in T1 emitting states compared with BNppy complexes 2-4, which results in strong SOC and fast kr. Thus, the phosphorescence efficiency of 1 is higher than that of 2. In addition, 5 and 6 have the balanced charge transport and better hole injection ability when the hole-transporting ligand is incorporated to 1. Therefore, 5 and 6 can server as promising candidates for efficient multifunctional phosphorescent OLED emitters owing to their ambipolar characters, balanced charge carrier injection/transport features and high phosphorescence quantum efficiency.

  2. Steering the Properties of MoOx Hole Transporting Layers in OPVs and OLEDs: Interface Morphology vs. Electronic Structure.

    PubMed

    Marchal, Wouter; Verboven, Inge; Kesters, Jurgen; Moeremans, Boaz; De Dobbelaere, Christopher; Bonneux, Gilles; Elen, Ken; Conings, Bert; Maes, Wouter; Boyen, Hans Gerd; Deferme, Wim; Van Bael, Marlies; Hardy, An

    2017-01-30

    The identification, fine-tuning, and process optimization of appropriate hole transporting layers (HTLs) for organic solar cells is indispensable for the production of efficient and sustainable functional devices. In this study, the optimization of a solution-processed molybdenum oxide (MoOx) layer fabricated from a combustion precursor is carried out via the introduction of zirconium and tin additives. The evaluation of the output characteristics of both organic photovoltaic (OPV) and organic light emitting diode (OLED) devices demonstrates the beneficial influence upon the addition of the Zr and Sn ions compared to the generic MoOx precursor. A dopant effect in which the heteroatoms and the molybdenum oxide form a chemical identity with fundamentally different structural properties could not be observed, as the additives do not affect the molybdenum oxide composition or electronic band structure. An improved surface roughness due to a reduced crystallinity was found to be a key parameter leading to the superior performance of the devices employing modified HTLs.

  3. Electroluminescence enhancement of glass/ITO/PEDOT:PSS/MEH-PPV/PEDOT:PSS/Al OLED by thermal annealing

    NASA Astrophysics Data System (ADS)

    Hewidy, Dina; Gadallah, A.-S.; Fattah, G. Abdel

    2017-02-01

    Manufacturing of glass/ITO/PEDOT:PSS/MEH-PPV/PEDOT:PSS/Al organic light emitting diode (OLED) by depositing PEDOT:PSS/MEH-PPV/PEDOT:PSS using spin coating has been reported. The roles of PEDOT:PSS in the structure have been reported. It allows transportation of holes from ITO to the highest occupied molecular orbit (HOMO) of MEH-PPV. In additions, it allows transportation of electrons from Al to lowest unoccupied molecular orbit (LUMO) of MEH:PPV. Further, it confines electrons in the LUMO of MEH:PPV due to the higher barrier of PEDOT:PSS of LUMO. The effect of thermal annealing on the current-voltage curve as well as on the electroluminescence intensity has been reported. The results show that the current increased from 25 mA to 52 mA at 7 V, when the sample was thermally annealed at 150 °C. Such enhancement in electrical injection leads to enhancement of the electroluminescence to a factor of 4.7 at the peak luminescence wavelength (∼592 nm). Reasons for electroluminescence improvement caused by thermal annealing have been proposed.

  4. Investigation of electrical and optical properties of MEH-PPV: ZnO nanocomposite films for OLED applications

    SciTech Connect

    Azhar, N. E. A. Shafura, A. K. Affendi, I. H. H. Shariffudin, S. S.; Saurdi, I.; Alrokayan, Salman A. H. Khan, Haseeb A.; Rusop, M.

    2016-07-06

    Recent investigations of the promising materials for optoelectronic have been demonstrated by introducing n-type inorganic material into conjugated polymer. The optical and electrical of nanocomposite films based on poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and zinc oxide (ZnO) nanostructured of various deposition layers (1 to 3 layers) have been investigated. The MEH-PPV: ZnO nanocomposite films were deposited using spin-coating technique. The surface morphology nanocomposite films were characterized using field emission scanning electron microscope. From surface profiler measurement, we found that the thickness of nanocomposite films increased as deposition time increased. The optical properties were measured using photoluminescence spectroscope. The photoluminescence (PL) spectra showed that two deposition layers is the highest intensity at visible region (green emission) due to high energy transfer from particles to the polymer. The current density for two layers sample is due to aggregation of conjugated polymer chain hence form excited interchain exciton for optical excitation. This study will provide better performance and suitable for optoelectronic device especially OLEDs application.

  5. [Archivos Españoles de Urología. Enrique Pérez Castro's direction (1944-1980)].

    PubMed

    Albacete, Mariano Pérez

    2008-01-01

    With the occasion of the centenary of the birth of Dr. Enrique Pérez Castro, founder, first director and editor of the journal Archivos Españoles de Urología, at this time when the issue No. 61 comes out, we performed a historic study of the evolution of the journal throughout the 36 years it was ruled by him, between April 1944 and December 1980. Complete review of the 158 issues, together with three extraordinary issues, included in the 31 volumes edited in the period Dr. Pérez Castro directed it. The journal, senior journal in Spanish Urology, developed its main objective of being the communication and knowledge exchange media, with the exposition of scientific works, among the members of the Spanish urological community who admitted it with interest and complete acceptation. The work and devotion of Dr. Pérez Castro as director conferred the journal a great quality and achieved to join it to the Spanish Association of Urology, which demonstrated its category and reinforced its diffusion, acceptation and continuity. It is by itself an exceptional document and splendid historic synopsis of our urology over the second half of the 20th century.

  6. Assignment of the disulfide bonds of Ole e 1, a major allergen of olive tree pollen involved in fertilization.

    PubMed

    González, E; Monsalve, R I; Puente, X S; Villalba, M; Rodríguez, R

    2000-01-01

    The most prevalent allergen from olive tree pollen, Ole e 1, consists of a single polymorphic polypeptide chain of 145 amino acids which includes six cysteine residues at positions 19, 22, 43, 78, 90 and 131. By using an homogeneous form of the allergen expressed in Pichia pastoris, the array of the disulfide bridges has been elucidated. Specific proteolysis with thermolysin and reverse-phase HPLC separation of the peptides allowed the determination of the disulfide bond between Cys43 and Cys78. Another thermolytic product, which contained three peptides linked by the remaining four cysteines, was digested with Glu-specific staphylococcal V8 protease and the products isolated by reverse-phase HPLC. Amino acid compositions and Edman degradation of the peptide products indicated the presence of the disulfide bonds at Cys19-Cys90 and Cys22-Cys131. These data can help in the analysis of the three-dimensional structure of the protein as well as in studies of its allergenic determinants.

  7. Investigation of electrical and optical properties of MEH-PPV: ZnO nanocomposite films for OLED applications

    NASA Astrophysics Data System (ADS)

    Azhar, N. E. A.; Shafura, A. K.; Affendi, I. H. H.; Shariffudin, S. S.; Saurdi, I.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-07-01

    Recent investigations of the promising materials for optoelectronic have been demonstrated by introducing n-type inorganic material into conjugated polymer. The optical and electrical of nanocomposite films based on poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and zinc oxide (ZnO) nanostructured of various deposition layers (1 to 3 layers) have been investigated. The MEH-PPV: ZnO nanocomposite films were deposited using spin-coating technique. The surface morphology nanocomposite films were characterized using field emission scanning electron microscope. From surface profiler measurement, we found that the thickness of nanocomposite films increased as deposition time increased. The optical properties were measured using photoluminescence spectroscope. The photoluminescence (PL) spectra showed that two deposition layers is the highest intensity at visible region (green emission) due to high energy transfer from particles to the polymer. The current density for two layers sample is due to aggregation of conjugated polymer chain hence form excited interchain exciton for optical excitation. This study will provide better performance and suitable for optoelectronic device especially OLEDs application.

  8. Blue light emitting Ir(III) compounds for OLEDs - new insights into ancillary ligand effects on the emitting triplet state.

    PubMed

    Rausch, Andreas F; Thompson, Mark E; Yersin, Hartmut

    2009-05-21

    The sky-blue emitting phosphorescent compound Ir(4,6-dFppy)(2)(acac) (FIracac) doped into different matrices is studied under ambient conditions and at cryogenic temperatures on the basis of broadband and high-resolution emission spectra. The emitting triplet state is found to be largely of metal-to-ligand charge transfer (MLCT) character. It is observed that different polycrystalline and amorphous hosts distinctly affect the properties of the triplet. Moreover, a comparison of FIracac with the related Ir(4,6-dFppy)(2)(pic) (FIrpic), differing only by the ancillary ligand, reveals obvious changes of properties of the emitting state. These observations are explained by different effects of acac and pic on the Ir(III) d-orbitals. In particular, the occupied frontier orbitals, strongly involving the t(2g)-manifold, and their splitting patterns are modified differently. This influences spin-orbit coupling (SOC) of the emitting triplet state to higher-lying (1,3)MLCT states. As a consequence, zero-field splittings, radiative decay rates, and phosphorescence quantum yields are changed. The important effects of SOC are discussed qualitatively and are related to the emission properties of the individual triplet substates, as determined from highly resolved spectra. The results allow us to gain a better understanding of the impact of SOC on the emission properties with the aim to develop more efficient triplet emitters for OLEDs.

  9. 7,7,8,8-Tetracyanoquinodimethane based molecular dopants for p-type doping of OLEDs: A theoretical investigation

    SciTech Connect

    Cosimbescu, Lelia; Padmaperuma, Asanga B.; Gaspar, Daniel J.

    2011-11-15

    The array of organic conductivity dopants used for organic light emitting devices (OLED) to reduce the operating voltage and improve power efficiency is extremely limited. Here we report a comparative theoretical study between newly proposed analogs and the standard state-of-the-art conductivity dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). We used density functional theory to determine the bond lengths, bond angles and electronic properties, such as the energy of the highest occupied molecular orbital (E{sub HOMO}) and lowest occupied molecular orbital (E{sub LUMO}) states, as well as the triplet energies of the novel structures (ET). The ground state structures of the proposed molecules were optimized at the B3LYP/6-31G* level. The results show that substitution of one or two fluorine groups in the F4-TCNQ core with a substituted phenyl ring or other electron withdrawing moieties, will not substantially affect the geometry of the molecule or its electronic ability to accept electrons. The most significant finding was that the phenyl substitutions onto the TCNQ core are nearly perpendicular to the TCNQ plane, and thus there is no electronic communication between the two rings. This is extremely important, as such extension of the {pi} conjugated system would negatively affect the E{sub LUMO} and thus the electron affinity of the molecule.

  10. Efficient solution-processed double-layer red OLEDs based on a new europium complex with a carbazole group.

    PubMed

    Liu, Jian; Miao, Jing-Sheng; Wu, Hong-Bin

    2015-06-01

    A new europium complex EuL3 (Phen) was used as guest dopant, and a blend of Polyvinylcarbazole and 2-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PVK and PBD) as host matrix. Efficient red organic light-emitting devices (OLEDs) with double-layer structures were manufactured via a solution-processed technique. The guest-doped levels were 1, 3 and 5 wt% relative to the blend mass, respectively. For the 1 wt% doping-level device, the luminous efficiency and luminance were up to 2.96 cd/A and 635.78 cd/m(2) with emissions from both EuL3 (Phen) and from the host; for the 3 wt% doping-level device, the maximum luminous efficiency and luminance were 1.01 cd/A and 370.91 cd/m(2) for the single emission from EuL3 (Phen) only.

  11. Photoluminescence of Alq3 - and Tb-activated aluminium-tris(8-hydroxyquinoline) complex for blue chip-excited OLEDs.

    PubMed

    Yawalkar, P W; Dhoble, S J; Thejo Kalyani, N; Atram, R G; Kokode, N S

    2013-01-01

    The tris(8-hydroxyquinoline)-aluminium complex is the most important and widely studied as electron transporting and green light emitting material. Alq(3) and Tb(x) Al((1-x)) q(3) have been synthesized (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) and blended films of Alq(3) and Tb(x) Al((1-x)) q(3) with PMMA and PS at different percentage weight (wt%) concentrations (e.g., 0.1, 1, 5, 10, 25 and 50 wt%) have been prepared. The synthesized materials and their blended thin films have been characterized by a photoluminescence (PL) technique; the synthesis and PL characterization are reported in this paper. The synthesized metal complex shows bright emission of green light with blue light excitation (440 nm) and the prepared Tb(x) Al((1-x)) q(3) phosphor may be applicable in blue chip-excited OLEDs for the newly developed wallpaper lighting technology. Copyright © 2012 John Wiley & Sons, Ltd.

  12. Application of flat panel OLED display technology for the point-of-care detection of circulating cancer biomarkers

    PubMed Central

    Katchman, Benjamin A.; Smith, Joseph T.; Obahiagbon, Uwadiae; Kesiraju, Sailaja; Lee, Yong-Kyun; O’Brien, Barry; Kaftanoglu, Korhan; Blain Christen, Jennifer; Anderson, Karen S.

    2016-01-01

    Point-of-care molecular diagnostics can provide efficient and cost-effective medical care, and they have the potential to fundamentally change our approach to global health. However, most existing approaches are not scalable to include multiple biomarkers. As a solution, we have combined commercial flat panel OLED display technology with protein microarray technology to enable high-density fluorescent, programmable, multiplexed biorecognition in a compact and disposable configuration with clinical-level sensitivity. Our approach leverages advances in commercial display technology to reduce pre-functionalized biosensor substrate costs to pennies per cm2. Here, we demonstrate quantitative detection of IgG antibodies to multiple viral antigens in patient serum samples with detection limits for human IgG in the 10 pg/mL range. We also demonstrate multiplexed detection of antibodies to the HPV16 proteins E2, E6, and E7, which are circulating biomarkers for cervical as well as head and neck cancers. PMID:27374875

  13. Effect of hole injection layer/hole transport layer polymer and device structure on the properties of white OLED.

    PubMed

    Cho, Ho Young; Park, Eun Jung; Kim, Jin-Hoo; Park, Lee Soon

    2008-10-01

    Copolymers containing carbazole and aromatic amine unit were synthesized by using Pd-catalyzed polycondensation reaction. The polymers were characterized in terms of their molecular weight and thermal stability and their UV and PL properties in solution and film state. The band gap energy of the polymers was also determined by the UV absorption and HOMO energy level data. The polymers had high HOMO energy level of 5.19-5.25 eV and work function close to that of ITO. The polymers were thus tested as hole injection/transport layer in the white organic light emitting diodes (OLED) by using 4,4'-bis(2,2-diphenyl-ethen-1-yl)diphenyl (DPVBi) as blue emitting material and 5,6,11,12-tetraphenylnaphthacene (Rubrene) as orange emitting dopant. The synthesized polymer, poly bis[6-bromo-N-(2-ethylhexyl)-carbazole-3-yl] was found to be useful as hole injection layer/hole transport layer (HIL/HTL) multifunctional material with high luminance efficiency and stable white color coordinate in the wide range of applied voltage.

  14. Steering the Properties of MoOx Hole Transporting Layers in OPVs and OLEDs: Interface Morphology vs. Electronic Structure

    PubMed Central

    Marchal, Wouter; Verboven, Inge; Kesters, Jurgen; Moeremans, Boaz; De Dobbelaere, Christopher; Bonneux, Gilles; Elen, Ken; Conings, Bert; Maes, Wouter; Boyen, Hans Gerd; Deferme, Wim; Van Bael, Marlies; Hardy, An

    2017-01-01

    The identification, fine-tuning, and process optimization of appropriate hole transporting layers (HTLs) for organic solar cells is indispensable for the production of efficient and sustainable functional devices. In this study, the optimization of a solution-processed molybdenum oxide (MoOx) layer fabricated from a combustion precursor is carried out via the introduction of zirconium and tin additives. The evaluation of the output characteristics of both organic photovoltaic (OPV) and organic light emitting diode (OLED) devices demonstrates the beneficial influence upon the addition of the Zr and Sn ions compared to the generic MoOx precursor. A dopant effect in which the heteroatoms and the molybdenum oxide form a chemical identity with fundamentally different structural properties could not be observed, as the additives do not affect the molybdenum oxide composition or electronic band structure. An improved surface roughness due to a reduced crystallinity was found to be a key parameter leading to the superior performance of the devices employing modified HTLs. PMID:28772483

  15. Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes - a new strategy for OLED materials.

    PubMed

    Ewen, Pascal R; Sanning, Jan; Koch, Tobias; Doltsinis, Nikos L; Strassert, Cristian A; Wegner, Daniel

    2014-01-01

    The improvement of molecular electronic devices such as organic light-emitting diodes requires fundamental knowledge about the structural and electronic properties of the employed molecules as well as their interactions with neighboring molecules or interfaces. We show that highly resolved scanning tunneling microscopy (STM) and spectroscopy (STS) are powerful tools to correlate the electronic properties of phosphorescent complexes (i.e., triplet emitters) with their molecular structure as well as the local environment around a single molecule. We used spectroscopic mapping to visualize several occupied and unoccupied molecular frontier orbitals of Pt(II) complexes adsorbed on Au(111). The analysis showed that the molecules exhibit a peculiar localized strong hybridization that leads to partial depopulation of a dz² orbital, while the ligand orbitals are almost unchanged. We further found that substitution of functional groups at well-defined positions can alter specific molecular orbitals without influencing the others. The results open a path toward the tailored design of electronic and optical properties of triplet emitters by smart ligand substitution, which may improve the performance of future OLED devices.

  16. Triplet harvesting with 100% efficiency by way of thermally activated delayed fluorescence in charge transfer OLED emitters.

    PubMed

    Dias, Fernando B; Bourdakos, Konstantinos N; Jankus, Vygintas; Moss, Kathryn C; Kamtekar, Kiran T; Bhalla, Vandana; Santos, José; Bryce, Martin R; Monkman, Andrew P

    2013-07-19

    Organic light-emitting diodes (OLEDs) have their performance limited by the number of emissive singlet states created upon charge recombination (25%). Recently, a novel strategy has been proposed, based on thermally activated up-conversion of triplet to singlet states, yielding delayed fluorescence (TADF), which greatly enhances electroluminescence. The energy barrier for this reverse intersystem crossing mechanism is proportional to the exchange energy (ΔEST ) between the singlet and triplet states; therefore, materials with intramolecular charge transfer (ICT) states, where it is known that the exchange energy is small, are perfect candidates. However, here it is shown that triplet states can be harvested with 100% efficiency via TADF, even in materials with ΔEST of more than 20 kT (where k is the Boltzmann constant and T is the temperature) at room temperature. The key role played by lone pair electrons in achieving this high efficiency in a series of ICT molecules is elucidated. The results show the complex photophysics of efficient TADF materials and give clear guidelines for designing new emitters. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Simultaneous Enhancement of Efficiency and Stability of Phosphorescent OLEDs Based on Efficient Förster Energy Transfer from Interface Exciplex.

    PubMed

    Zhang, Dongdong; Cai, Minghan; Zhang, Yunge; Bin, Zhengyang; Zhang, Deqiang; Duan, Lian

    2016-02-17

    Exciplex forming cohosts have been widely adopted in phosphorescent organic light-emitting diodes (PHOLEDs), achieving high efficiency with low roll-off and low driving voltage. However, the influence of the exciplex-forming hosts on the lifetimes of the devices, which is one of the essential characteristics, remains unclear. Here, we compare the influence of the bulk exciplex and interface exciplex on the performances of the devices, demonstrating highly efficient orange PHOLEDs with long lifetime at low dopant concentration by efficient Förster energy transfer from the interface exciplex. A bipolar host, (3'-(4,6-diphenyl-1,3,5-triazin-2-yl)-(1,1'-biphenyl)-3-yl)-9-carbazole (CzTrz), was adopted to combine with a donor molecule, tris(4-(9H-carbazol-9-yl)phenyl)amine (TCTA), to form exciplex. Devices with energy transfer from the interface exciplex achieve lifetime almost 2 orders of magnitude higher than the ones based on bulk exciplex as the host by avoiding the formation of the donor excited states. Moreover, a highest EQE of 27% was obtained at the dopant concentration as low as 3 wt % for a device with interface exciplex, which is favorable for reducing the cost of fabrication. We believe that our work may shed light on future development of ideal OLEDs with high efficiency, long-lifetime, low roll-off and low cost simultaneously.

  18. The allergenic structure of the thaumatin-like protein Ole e 13 is degraded by processing of raw olive fruits.

    PubMed

    Torres, M; Alvarez-García, E; Bartra, J; Alcántara, M; Palomares, O; Villalba, M; Rodríguez, R

    2014-01-01

    The thaumatin-like protein (TLP) Ole e 13 in raw olive fruit is responsible for occupational allergy in olive oil mill workers. However, these workers do not experience allergic symptoms after ingestion of edible olive. To analyze the presence of IgE-reactive TLP in raw and edible olive fruit and to assess the allergenic potency of both sources. The content of TLP in raw and edible olive fruit protein extracts was analyzed using immunoblotting with sera from allergic patients and with olive TLP-specific IgG. The structural and immunological stability of TLP were assayed using immunoblotting after treatment of both raw olive and purified TLP with 0.25 M NaOH solution for 24 hours. Olive pollen extract was investigated by immunoblotting for TLP content. The TLP contained in raw olive fruit was not present in edible olives as a result of maceration before human consumption. No TLP was detected in olive pollen using specific IgG or sera from patients allergic to olive fruit. Sera from patients allergic to olive pollen did not react with purified TLP. IgE-reactive TLP is not present in edible olive, thus explaining the low number of patients allergic to this highly consumed fruit. Patients allergic to olive pollen are not sensitized toTLP and, therefore, not expected to be at risk of food allergy to olive fruit or TLP plant sources.

  19. [Assessment of the quality of scientific evidence in Anales Españoles de Pediatría].

    PubMed

    González De Dios, J

    2001-04-01

    Evidence-based medicine is a new scientific paradigm that aims to use medical literature more effectively in guiding medical practice. The aim of this study was to assess the quality of scientific evidence in Spanish pediatric articles. Original articles published in Anales Españoles de Pediatría during a 6.5year period (n733) were compared with those published in Pediatrics during a 1.5year period (n300). The quality of scientific evidence in Anales was high in only 3% of original articles (randomized clinical trials). It was average in 30.4% (non-randomized clinical trials, cohort studies, case-control studies) and poor in 66.6% (descriptive studies, case reports, etc.). Only 10.2% of articles used appropriate methodological concepts according to evidence-based medicine. These concepts were mainly "soft" (odds ratio, relative risk, confidence interval) and no "hard" concepts (number needed to treat, likelihood ratio, odds pretest) were detected. The pediatric specialty showing the highest quality of scientific evidence, greatest use of appropriate methodological concepts and greatest statistical accessibility was pneumology. The first step in improving the quality of scientific evidence would be to establish collaboration between epidemiologists and/or biostatisticians. The evidence-based bibliometric indicators found in Pediatrics serve as a gold standard for Anales.

  20. Theoretical studies on electronic structures and photophysical properties of anthracene derivatives as hole-transporting materials for OLEDs.

    PubMed

    Chitpakdee, Chirawat; Namuangruk, Supawadee; Khongpracha, Pipat; Jungsuttiwong, Siriporn; Tarsang, Ruangchai; Sudyoadsuk, Taweesak; Promarak, Vinich

    2014-05-05

    The electronic structures and photophysical properties of anthracene derivatives as hole-transporting materials (HTM) in OLEDs have been studied by DFT and TD-DFT methods. Thiophene and triphenylamine (TPA) moieties are used as substituents in anthracene based HTMs providing FATn and FAPn compounds (n=1-2), respectively. The calculated electronic levels by B3LYP show proper energy matching of FAPn and hole-injecting layer (HIL), indicating that the hole-transports of the FAPn compounds are better than the FATn compounds. The photophysical properties calculated by TD-B3LYP elucidate that TPA in FAPn compounds acts as electron donating group and induces charge transfer character in the absorptions. Furthermore, the calculated ionization potential (IP), electron affinity (EA) and reorganization energies also revealed that the extended FAP2 compound has the highest charge-transporting ability among the studied compounds. The calculated results are consistent to our experimental observations showing that FAP2 exhibits bright fluorescence with highest quantum yield in electroluminescent devices. Understanding of these properties is useful for further design of new HTMs of desired properties, such as high efficiency and stability.

  1. Concepts for the material development of phosphorescent organic materials processable from solution and their application in OLEDs

    NASA Astrophysics Data System (ADS)

    Janietz, S.; Krueger, H.; Thesen, M.; Salert, B.; Wedel, A.

    2014-10-01

    One example of organic electronics is the application of polymer based light emitting devices (PLEDs). PLEDs are very attractive for large area and fine-pixel displays, lighting and signage. The polymers are more amenable to solution processing by printing techniques which are favourable for low cost production in large areas. With phosphorescent emitters like Ir-complexes higher quantum efficiencies were obtained than with fluorescent systems, especially if multilayer stack systems with separated charge transport and emitting layers were applied in the case of small molecules. Polymers exhibit the ability to integrate all the active components like the hole-, electron-transport and phosphorescent molecules in only one layer. Here, the active components of a phosphorescent system - triplet emitter, hole- and electron transport molecules - can be linked as a side group to a polystyrene main chain. By varying the molecular structures of the side groups as well as the composition of the side chains with respect to the triplet emitter, hole- and electron transport structure, and by blending with suitable glass-forming, so-called small molecules, brightness, efficiency and lifetime of the produced OLEDs can be optimized. By choosing the triplet emitter, such as iridium complexes, different emission colors can be specially set. Different substituted triazine molecules were introduced as side chain into a polystyrene backbone and applied as electron transport material in PLED blend systems. The influence of alkyl chain lengths of the performance will be discussed. For an optimized blend system with a green emitting phosphorescent Ir-complex efficiencies of 60 cd/A and an lifetime improvement of 66.000 h @ 1000 cd/m2 were achieved.

  2. Pyridylpyrazole N^N ligands combined with sulfonyl-functionalised cyclometalating ligands for blue-emitting iridium(iii) complexes and solution-processable PhOLEDs.

    PubMed

    Benjamin, Helen; Fox, Mark A; Batsanov, Andrei S; Al-Attar, Hameed A; Li, Chensen; Ren, Zhongjie; Monkman, Andrew P; Bryce, Martin R

    2017-08-22

    A series of blue iridium(iii) complexes (12-15) comprising sulfonyl-functionalised phenylpyridyl cyclometalating ligands and pyridylpyrazole N^N ligands are reported, with an X-ray crystal structure obtained for 12. The complexes are highly emissive with photoluminescence quantum yields of 0.52-0.70 in dichloromethane solutions: two of the complexes (12 and 14) show emissions at λ 457 nm which is considerably blue-shifted compared to the archetypal blue emitter FIrpic (λmax 468 nm). The short excited state lifetimes (1.8-3.3 μs) and spectral profiles are consistent with phosphorescence from a mixture of ligand-centred and MLCT excited states. Density functional (DFT) and time dependent DFT (TD-DFT) calculations are in agreement with the electrochemical properties and the blue phosphorescence of the complexes. The additional mesityl substituent on the pyridylpyrazole ligand of 12 and 13 enhances the solubility of the complexes facilitating thin film formation by solution processing. Phosphorescent organic light-emitting diodes (PhOLEDs) have been fabricated using 12 or 13 in a solution-processed single-emitting layer using either poly(vinylcarbazole) (PVK) or 1,3-bis(N-carbazolyl)benzene (mCP) as host. The most blue-shifted electroluminescence (λ 460 nm, CIEx,y 0.15, 0.21) is obtained for an OLED containing complex 12 and mCP, with a brightness of 5400 cd m(-2) at 10 V which is high for PhOLEDs with similar blue CIE coordinates using a solution-processed emitter layer.

  3. Dissecting the accountability of parameterized and parameter-free single-hybrid and double-hybrid functionals for photophysical properties of TADF-based OLEDs

    NASA Astrophysics Data System (ADS)

    Alipour, Mojtaba; Karimi, Niloofar

    2017-06-01

    Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters are an attractive category of materials that have witnessed a booming development in recent years. In the present contribution, we scrutinize the accountability of parameterized and parameter-free single-hybrid (SH) and double-hybrid (DH) functionals through the two formalisms, full time-dependent density functional theory (TD-DFT) and Tamm-Dancoff approximation (TDA), for the estimation of photophysical properties like absorption energy, emission energy, zero-zero transition energy, and singlet-triplet energy splitting of TADF molecules. According to our detailed analyses on the performance of SHs based on TD-DFT and TDA, the TDA-based parameter-free SH functionals, PBE0 and TPSS0, with one-third of exact-like exchange turned out to be the best performers in comparison to other functionals from various rungs to reproduce the experimental data of the benchmarked set. Such affordable SH approximations can thus be employed to predict and design the TADF molecules with low singlet-triplet energy gaps for OLED applications. From another perspective, considering this point that both the nonlocal exchange and correlation are essential for a more reliable description of large charge-transfer excited states, applicability of the functionals incorporating these terms, namely, parameterized and parameter-free DHs, has also been evaluated. Perusing the role of exact-like exchange, perturbative-like correlation, solvent effects, and other related factors, we find that the parameterized functionals B2π-PLYP and B2GP-PLYP and the parameter-free models PBE-CIDH and PBE-QIDH have respectable performance with respect to others. Lastly, besides the recommendation of reliable computational protocols for the purpose, hopefully this study can pave the way toward further developments of other SHs and DHs for theoretical explorations in the field of OLEDs technology.

  4. Mechanisms of AZO workfunction tuning for anode use in OLEDs: Surface dipole manipulation with plasma treatments versus nanoscale WOx and VOx interfacial layers

    NASA Astrophysics Data System (ADS)

    Jha, Jitendra Kumar; Sun, Wei; Du, Jincheng; Shepherd, Nigel D.

    2017-05-01

    Zinc oxide (ZnO) and aluminum doped zinc oxide (AZO) are potential low cost alternative anodes to indium tin oxide (ITO) for organic light emitting diodes (OLEDs). However, their smaller workfunctions compared to ITO lead to higher hole injection barriers, and methods of tuning their workfunctions are of significant technological interest. Ultraviolet and x-ray photoelectron spectroscopies together with density functional theory based first principles calculations indicate that with CFx plasma treatments, increased workfunction can be achieved by -CF3 or -F adsorption on ZnO surfaces, due to creation of a surface dipole moment with electron transfer to F. Modification of AZO surfaces with nanoscopic (˜3 nm) VOx and WOx layers yielded workfunction increases due to the larger workfunction of the add-layers. Deviations from stoichiometry (oxygen vacancies) result in reduced metal cations (W5+, W4+, V4+, and V3+), leading to partial filling of the metal d band, and formation of associated gap states. Current-voltage characterization of hole-only devices reveals that the increased workfunction of the surface modified anodes facilitated improved band alignment and hole injection compared to as-deposited AZO. The luminous efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) of OLEDs with AZO/WOx anodes were 62%, 100%, and 85% better than ITO. OLEDs with AZO/VOx anodes exhibited 62%, 75%, and 85% better LE, PE, and EQE, than ITO, respectively. The enhanced performance is ascribed to improved hole injection, charge balance, and radiative recombination efficiency. Thus, the results describe two physical mechanisms by which the workfunction of inexpensive alternatives to ITO can be tuned to yield comparable or enhanced performance.

  5. Structurally integrated organic light-emitting device (OLED)-based sensors for industrial and environmental security: sensors for hydrazine and anthrax

    NASA Astrophysics Data System (ADS)

    Zhou, Zhaoqun; Shinar, Ruth; Choudhury, Bhaskar; Tabatabai, Louisa B.; Liao, Chuxiong; Shinar, Joseph

    2005-11-01

    The application of the new compact platform of structurally integrated, photoluminescent (bio)chemical sensors, where the photoluminescence (PL) excitation source is an OLED, to the detection of hydrazine and anthrax, is described. The hydrazine sensor is based on the reaction between nonluminescent anthracene-2,3-dicarboxaldehyde and hydrazine or hydrazine sulfate, which generates a luminescent product. The anthrax sensor is based on a Foerster resonance energy transfer (FRET) assay, where the anthrax-secreted lethal factor enzyme cleaves certain labeled peptides at a specific site. The cleaving separates the FRET donor-acceptor pair, resulting in an increase in the PL of the donor, which was previously absorbed by the acceptor.

  6. Injection, transport, absorption and phosphorescence properties of a series of blue-emitting Ir(III) emitters in OLEDs: a DFT and time-dependent DFT study.

    PubMed

    Li, Xiao-Na; Wu, Zhi-Jian; Si, Zhen-Jun; Zhang, Hong-Jie; Zhou, Liang; Liu, Xiao-Juan

    2009-08-17

    Quantum-chemistry methods were explored to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of blue-emitting Ir(III) complexes {[(F(2)-ppy)(2)Ir(pta -X/pyN4)], where F(2)-ppy = (2,4-difluoro)phenylpyridine; pta = pyridine-1,2,4-triazole; X = phenyl(1); p-tolyl (2); 2,6-difluororophenyl (3); -CF(3) (4), and pyN4 = pyridine-1,2,4-tetrazolate (5)}, which are used as emitters in organic light-emitting diodes (OLEDs). The mobility of hole and electron were studied computationally based on the Marcus theory. Calculations of Ionization potentials (IPs) and electron affinities (EAs) were used to evaluate the injection abilities of holes and electrons into these complexes. The reasons for the lower EL efficiency and phosphorescence quantum yields in 3-5 than in 1and 2 have been investigated. These new structure-property relationships can guide an improved design and optimization of OLED devices based on blue-emitting phosphorescent Ir(III) complexes.

  7. Optically Detected Magnetic Resonance (ODMR) Studies Critical to the Determination of the Yield of Singlet Excitons in Fluorescence-Based OLEDs

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph

    2005-03-01

    Recent ODMR studies, including (1) photoluminescence (PL)-detected magnetic resonance (PLDMR) of small π-conjugated molecules, (2) electroluminescence (EL)- and electrically-detected magnetic resonance (ELDMR and EDMR, respectively) studies of small molecular OLEDs, (3) double modulation-PLDMR studies of π-conjugated polymers, and (4) joint PLDMR and thermally stimulated luminescence (TSL) studies of π-conjugated polymers are reviewed. The results of each of these studies are inconsistent with the model in which the positive spin 1/2 (polaron) resonance is due to enhanced delayed PL from nongeminate polaron recombination (``the delayed PL model''). Since the delayed PL model is the basis for the previous ODMR studies which predicted the yield of singlet excitons (SEs) in OLEDs, the recent ODMR studies reopen this issue. It is shown that all of the ODMR results obtained to date are consistent with ``the quenching model,'' in which the population of polarons and triplet excitons (TEs) is reduced by magnetic resonance conditions, and leads to reduced quenching of SEs by polarons and TEs. A detailed quantitative model confirms that the mechanism which causes the reduction in the polaron and TE population is the enhanced annihilation of TEs by polarons, whose populations are much larger than that of SEs under normal excitation conditions. *Operated by Iowa State University for the US Department of Energy under Contract No. W-7405-Eng-82.

  8. Triplet state properties of the OLED emitter Ir(btp)2(acac): characterization by site-selective spectroscopy and application of high magnetic fields.

    PubMed

    Finkenzeller, Walter J; Hofbeck, Thomas; Thompson, Mark E; Yersin, Hartmut

    2007-06-11

    The well-known red emitting complex Ir(btp)2(acac) (bis(2-(2'-benzothienyl)-pyridinato-N,C3')iridium(acetylacetonate)), frequently used as emitter material in OLEDs, has been investigated in a polycrystalline CH2Cl2 matrix. The studies were carried out under variation of temperature down to 1.2 K and at magnetic fields up to B=10 T. Highly resolved emission and excitation spectra of several specific sites are obtained by site-selective spectroscopy. For the preferentially investigated site (I-->0 at 16268 cm-1), the three substates I, II, and III of the T1 triplet state are separated by DeltaEII-I=2.9 cm-1 and DeltaEIII-I=25.0 cm-1, respectively. DeltaEIII-I represents the total zero-field splitting (ZFS). The individual decay times of these substates are tauI=150 micros, tauII=58 micros, and tauIII=2 micros, respectively. The long decay time of the lowest substate I indicates its almost pure triplet character. The time for relaxation from state II to state I (spin-lattice relaxation, SLR) is as long as 22 micros at T=1.5 K, while the thermalization between the two lower lying substates and substate III is fast. Application of a magnetic field induces Zeeman mixing of the substates of T1, resulting in an increased splitting between the two lower lying substates from 2.9 cm-1 at zero field to, for example, 6.8 cm-1 at B=10 T. Further, the decay time of the B-field perturbed lowest substate IB decreases by a factor of about 7 up to 10 T. The magnetic field properties clearly show that the three investigated states belong to the same triplet parent term of one single site. Other sites show a similar behavior, though the values of ZFS vary between 15 and 27 cm-1. Since the amount of ZFS reflects the extent of MLCT (metal-to-ligand charge transfer) parentage, it can be concluded that the emitting state T1 is a 3LC (ligand centered) state with significant admixtures of 1,3MLCT (metal-to-ligand charge transfer) character. Interestingly, the results show that the MLCT

  9. Luminescent properties of a di-hydrazone derived from the antituberculosis agent isoniazid: Potentiality as an emitting layer constituent for OLED fabrication

    NASA Astrophysics Data System (ADS)

    Moraes, Rafaela S.; Aderne, Rian E.; Cremona, Marco; Rey, Nicolás A.

    2016-02-01

    Hydrazones constitute a class of compounds presenting azomethine R‧R″Nsbnd Ndbnd CHsbnd R hydrogens, which show diverse properties and a wide range of applications. A hydrazone derived from the antituberculosis drug isoniazid, namely, N,N‧-diisonicotinoyl-2-hydroxy-5-methylisophthalaldehyde hydrazone (DMD) was synthesized and chemically characterized. Its luminescent properties were also investigated, as well as the possibility of using this compound as a constituent of the emitting layer for the fabrication of OLEDs. Co-deposited devices were fabricated using the organic molecule BSBF as matrix and DMD as dopant. All the devices presented a broad electroluminescence band, in which it was possible to recognize the DMD emission along with emissions of some of the other organic layers. The best results were obtained with 35% DMD doping, achieving a luminance of about 35 cd/m2.

  10. Comparison study of transparent RF-sputtered ITO/AZO and ITO/ZnO bilayers for near UV-OLED applications

    NASA Astrophysics Data System (ADS)

    Rezaie, Mahdiyar Nouri; Manavizadeh, Negin; Abadi, Ehsan Mohammadi Nasr; Nadimi, Ebrahim; Boroumand, Farhad Akbari

    2017-01-01

    Hybrid inorganic/organic light-emitting diodes have attracted much attention in the field of luminescent electronics due to the desired incorporation of high optoelectronic features of inorganic materials with the processability and variety of organic polymers. To generate and emit a near ultraviolet (N-UV) ray, wide band gap semiconductors can be applied in the organic light-emitting diodes (OLEDs). In this paper, zinc oxide (ZnO) and aluminum-doped ZnO (AZO) thin films are deposited by radio frequency (RF) sputtering above the ITO electrode and poly [2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) conjugated polymer is utilized as a complementary p-type semiconductor in OLED structure. The impact of ZnO and AZO thickness on the structural, electrical, optical and morphological properties of ITO/AZO and ITO/ZnO bilayers are scrutinized and compared. Results show that with the enlargement of both ZnO and AZO film thickness, the physical properties are gradually improved resulting in the better quality of transparent conducting thin film. The average electrical resistivity of 8.4 × 10-4 and 1.1 × 10-3 Ω-cm, average sheet resistance of 32.9 and 42.3 Ω/sq, average transmittance of 88.3 and 87.3% and average FOM of 1.0 × 104 and 7.4 × 103 (Ω-cm)-1 are obtained for ITO/AZO and ITO/ZnO bilayers, respectively. Moreover, comparing the results indicates that the strain and the stress within the ITO/AZO bilayer are decreased nearly 19% with respect to ITO/ZnO bilayer which yield higher quality of crystal. Consequently, the physical properties of ITO/AZO bilayer is found to be superior regarding ITO/ZnO bilayer. For fabricated UV-OLEDs, the turn-on voltages, the characteristic energy (Et) and the total concentration of traps (Nt) for the devices with the structures of ITO/ZnO/MEH-PPV/Al and ITO/AZO/MEH-PPV/Al are obtained 12 and 14 V, 0.108 and 0.191 eV, 9.33 × 1016 and 5.22 × 1016 cm-3, respectively. Furthermore, according to the electroluminescence

  11. Preparation of CaO as OLED getter material through control of crystal growth of CaCO{sub 3} by block copolymers in aqueous solution

    SciTech Connect

    Park, Jae-Hyung; Oh, Seong-Geun

    2009-01-08

    As the starting materials of organic light-emitting diode (OLED) getter, calcium carbonate (CaCO{sub 3}) particles with various shapes and crystal structures have been successfully prepared with additives (L64 or PEGPG), which contain blocks of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO). These CaCO{sub 3} particles were calcinated into highly crystalline calcium oxide (CaO) nanoparticles with high capacity of water adsorption up to 14.23 wt.%. The CaCO{sub 3} and CaO particles prepared at various conditions were characterized using the field emission scanning electron microscopy (FE-SEM), Fourier transform infrared microscopy (FT-IR), X-ray powder diffraction (XRD), and dynamic vapor sorption (DVS) method.

  12. Synthesis and application of pyridine-based ambipolar hosts: control of charge balance in organic light emitting devices (OLEDs) by chemical structure modification

    SciTech Connect

    Koech, Phillip K.; Polikarpov, Evgueni; Rainbolt, James E.; Cosimbescu, Lelia; Swensen, James S.; Von Ruden, Amber L.; Padmaperuma, Asanga B.

    2010-11-05

    Pyridine-based host materials were synthesized via Grignard metathesis of bromopyridines to provide the required organometallic reagent. The isomeric hosts (4-(9H-carbazol-9-yl)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A4), (5-(9H-carbazol-9-yl)pyridin-2-yl)diphenylphosphine oxide (HM-A5), and (5-(diphenylamino)pyridin-2-yl)diphenylphosphine oxide (HM-A6), (4-(diphenylamino)phenyl)(phenyl)(pyridin-3-yl)phosphine oxide (HM-A8) have similar frontier orbital energies. Organic light emitting devices (OLEDs) fabricated using the series of the host materials demonstrate that small structural modification of the host results in significant change in charge transporting ability.

  13. Studies on high power ultrasonic microembossing and organic light emitting diodes (OLEDs) for the creation of lab-on-CD devices for sensor related applications

    NASA Astrophysics Data System (ADS)

    Vengasandra, Srikanth G.

    This study demonstrates the application of High Power Ultrasonic Microembossing Technology (HPUMT) in producing microfeatures on polymer substrates. The work reviews a novel method of obtaining flash free and precise microfeatures by manipulating the material density through microcellular foaming. The microfeatures created on the polymer substrates were further characterized by analyzing the feature depth with respect to the critical ultrasonic embossing operating parameters such as embossing heating times (s), embossing amplitude (microm) at a constant embossing trigger force (N). An experiment design was constructed and performed to characterize the parameters on foamed and unfoamed (or regular) versions of polystyrene (PS) and polypropylene (PP) sample materials. Results indicated feature depth was proportional to heating times, amplitude and force. It was also seen the maximum depth was achieved in the shortest cycle times with higher amplitudes and forces of operation. HPUMT was further studied to create functional network of microchannels functioned as reservoirs, reaction chamber and burst or gate valves to form a centrifugal biosensing platform that is also referred to as a lab-on-CD or a bio-CD device. The surface energy of the polymer substrates was increased to enable fluid flow by using a surfactant based organic coating to facilitate hydrophilicity. Using an organic light emitting diode (OLEDs) as an electroluminescence source provided luminescence decay results in good agreement with stern-volmer relationship. The functionality of the OLED-coupled lab-on-CD device was further tested in measuring unknown concentrations of a particular analyte in corn slurry sample which contained numerous contaminants. Combinatorial multianalyte sensing was also made possible on a single bio-CD using a four photodetector (PD) quad preamp disk sensor.

  14. Differences in Cumulative Exposure and Adherence to Tenofovir in the VOICE, iPrEx OLE, and PrEP Demo Studies as Determined via Hair Concentrations.

    PubMed

    Koss, Catherine A; Bacchetti, Peter; Hillier, Sharon L; Livant, Edward; Horng, Howard; Mgodi, Nyaradzo; Mirembe, Brenda G; Gomez Feliciano, Kailazarid; Horn, Stephanie; Liu, Albert Y; Glidden, David V; Grant, Robert M; Benet, Leslie Z; Louie, Alexander; van der Straten, Ariane; Chirenje, Z Mike; Marrazzo, Jeanne M; Gandhi, Monica

    2017-03-02

    Pre-exposure prophylaxis (PrEP) with oral tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) prevented HIV acquisition among men and women in several trials and is broadly recommended. In the VOICE and FEM-PrEP trials, however, TDF/FTC-based PrEP did not prevent HIV acquisition among women in eastern and southern Africa. Tenofovir was detected in plasma, reflecting exposure and adherence in recent days, in fewer than one-third of participants. Drug concentrations in hair, which represent cumulative exposure and adherence over weeks to months, have never previously been examined among women on PrEP. We compared tenofovir hair concentrations among women assigned to oral TDF/FTC in the VOICE trial to those among men and transgender women enrolled in 2 open-label PrEP studies, the iPrEx open-label extension (OLE) study and the U.S. PrEP Demonstration Project (PrEP Demo). Tenofovir hair concentrations were detectable in 55% of person-visits in VOICE, 75% of person-visits in iPrEx OLE (p = .006), and 98% of person-visits in PrEP Demo (p < .001). Median tenofovir hair concentrations corresponded to an estimated 0.2, 2.9, and 6.0 TDF/FTC doses taken per week in the three studies, respectively. In VOICE, combining tenofovir concentration data from plasma and hair suggested inconsistent, low-level product use. Incorporation of both short- and long-term adherence measures may allow for an improved understanding of patterns of drug-taking among women during global PrEP roll-out.

  15. Rational design of aggregation-induced emission luminogen with weak electron donor-acceptor interaction to achieve highly efficient undoped bilayer OLEDs.

    PubMed

    Chen, Long; Jiang, Yibin; Nie, Han; Hu, Rongrong; Kwok, Hoi Sing; Huang, Fei; Qin, Anjun; Zhao, Zujin; Tang, Ben Zhong

    2014-10-08

    In this work, two tailored luminogens (TPE-NB and TPE-PNPB) consisting of tetraphenylethene (TPE), diphenylamino, and dimesitylboryl as a π-conjugated linkage, electron donor, and electron acceptor, respectively, are synthesized and characterized. Their thermal stabilities, photophysical properties, solvachromism, fluorescence decays, electronic structures, electrochemical behaviors, and electroluminescence (EL) properties are investigated systematically, and the impacts of electron donor-acceptor (D-A) interaction on optoelectronic properties are discussed. Due to the presence of a TPE unit, both luminogens show aggregation-induced emission, but strong D-A interaction causes a decrease in emission efficiency and red-shifts in photoluminescence and EL emissions. The luminogen, TPE-PNPB, with a weak D-A interaction fluoresces strongly in solid film with a high fluorescence quantum yield of 94%. The trilayer OLED [ITO/NPB (60 nm)/TPE-PNPB (20 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] utilizing TPE-PNPB as a light emitter shows a peak luminance of 49 993 cd m(-2) and high EL efficiencies up to 15.7 cd A(-1), 12.9 lm W(-1), and 5.12%. The bilayer OLED [ITO/TPE-PNPB (80 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] adopting TPE-PNPB as a light emitter and hole transporter simultaneously affords even better EL efficiencies of 16.2 cd A(-1), 14.4 lm W(-1), and 5.35% in ambient air, revealing that TPE-PNPB is an eximious p-type light emitter.

  16. Molecular cloning and expression of active Ole e 3, a major allergen from olive-tree pollen and member of a novel family of Ca2+-binding proteins (polcalcins) involved in allergy.

    PubMed

    Ledesma, A; Villalba, M; Batanero, E; Rodríguez, R

    1998-12-01

    A cDNA encoding Ole e 3, a major allergen from olive-tree pollen, has been cloned and sequenced. A strategy based on two-step PCR amplification towards the 5' end and 3' end, with an internal specific primer, has been used. The isolated cDNA contains an open reading frame coding for a polypeptide of 84 amino acids, which is in agreement with the composition and molecular mass of the natural allergen, exhibiting two 12-residue segments homologous to Ca2+-binding sites of EF-hand type. The cDNA was inserted into the pET-11b expression vector and over-expressed in Escherichia coli. The purified recombinant protein shows identical secondary structure to that of the natural allergen and is able to bind both IgE from sera of patients allergic to olive pollen and polyclonal antibodies raised against olive-pollen Ole e 3. The capacity of binding Ca2+ has been demonstrated for both natural and recombinant allergens. RNA transcripts of Ole e 3 were only detected in pollen tissue. Northern-blot and Western-blot analyses of poly(A)+ RNA and protein extracts, respectively, obtained from a variety of olive-tree-related and nonrelated mature pollens demonstrated the presence of Ole e 3 homologous proteins. This indicates a sequence conservation and widespread distribution for this family of Ca2+-binding proteins that can be responsible for allergenic cross-reactivity. We suggest the tentative generic name of polcalcins for the members of this family of Ca2+-binding proteins from pollen.

  17. Effect of the substituents on the photophysical, electrochemical and electroluminescence properties of OLED dopant Iridium bis(2-phenylbenzothiozolato- N,C2')(acetylacetonate)

    NASA Astrophysics Data System (ADS)

    Ivanov, P.; Tomova, R.; Petrova, P.

    2014-12-01

    The effect of two substituents: clorine and 1,3-diphenylpropane-1,3-dionate, placed on different position in the molecule of Iridium (III) bis(2-phenylbenzothiozolato-N,C2')- (acetylacetonate) (bt)2Ir(acac), on its electrochemical behaviour, photophysical and electroluminescence properties were investigated. Three complexes (bt)2Ir(acac), Iridium (III) bis[2-(4-chlorophenyl)benzothiazolato-N,C2']-acetylacetonate (Clbt)2Ir(acac), in which the Cl atom was introduced on the 4-position in the benzothiazole ring, and the new Iridium (Ill) bis[2 -phenylbenzothiazolato -N,C2'] -(1,3 -diphenylpropane-1,3 -dionate) (bt)2Ir(dbm), where ancillary acetylacetonate ligand was replaced by 1,3-diphenylpropane-1,3-dionate, were synthesized and characterised by 1H-NMR and elemental analysis. The HOMO/LUMO energy levels of the complexes were determined by cyclic voltammetry (CV) and their properties were established by UV-Visible and fluorescence spectroscopy. The application of (Clbt)2Ir(acac), (bt)2Ir(bsm) and (bt)2Ir(acac) as dopants in hole transporting layer (HTL) of Organic light- emitting diodes(OLEDs). It was found that with respect to the reference (bt)2Ir(acac): both LUMO and HOMO of the substituted complexes were shifted to more positive values accordingly with 0.23 and 0.19 eV for (Clbt)2Ir(acac) and 0.14 and 0.12 eV for (bt)2Ir(dbm). OLEDs doped with 1 w% of the complexes irradiated the warm white light with Commission internationale de l'eclairage (CIE) coordinates: 0.24;0.38 for (Clbt)2Ir(acac), 0.30;0.44 for (bt)2Ir(acac) and 0.28;0.46 for (bt)2Ir(dbm). Devices doped with 10 w% of all complexes irradiated in the yellow orange region of the spectrum.

  18. Matrix effects on the triplet state of the OLED emitter Ir(4,6-dFppy)2(pic) (FIrpic): investigations by high-resolution optical spectroscopy.

    PubMed

    Rausch, Andreas F; Thompson, Mark E; Yersin, Hartmut

    2009-03-02

    The sky-blue emitting compound Ir(4,6-dFppy)(2)(pic) (iridium(III)bis[2-(4',6'-difluorophenyl)pyridinato-N,C(2')]-picolinate), commonly referred to as FIrpic and representing a well-known emitter material for organic light emitting diodes (OLEDs), has been investigated in detail by optical spectroscopy. Studies at temperatures from T = 1.5 K to T = 300 K were carried out in CH(2)Cl(2) and tetrahydrofuran (THF). In CH(2)Cl(2), two discrete sites were observed at cryogenic temperatures and studied by site-selective, high-resolution spectroscopy. The investigations reveal that the molecules located at the two sites exhibit distinctly different photophysical properties. For example, the three substates I, II, and III of the emitting triplet state T(1) of the low-energy site A show a distinctly larger zero-field splitting (ZFS) and exhibit shorter individual decay times than observed for the high-energy site B. The vibrational satellite structures in the emission spectra of the substates I(A) and I(B) exhibit clear differences in the ranges of metal-ligand (M-L) vibrations. For the compound studied in a polycrystalline THF host, giving only strongly inhomogeneously broadened spectra, the ZFS parameters and substate decay times vary in a similar range as observed for the two discrete sites in the CH(2)Cl(2) matrix. Thus, the amount of ZFS, the emission decay times, and also the intensities of the M-L vibrational satellites are affected by the matrix cage, that is, the host environment of the emitting complex. These properties are discussed with respect to variations of spin-orbit coupling routes. In particular, changes of d-orbital admixtures, that is, differences of the metal-to-ligand charge transfer (MLCT) character in the emitting triplet, play an important role. The matrix effects are expected to be also of importance for FIrpic and other Ir(III) compounds when applied as emitters in amorphous OLED matrixes.

  19. X-Band Electroluminescence (EL)- and Electrically-Detected Magnetic Resonance (ELDMR and EDMR) Studies of 8-tris(hydroxy quinoline) Al (Alq3)-Based Organic Light-Emitting Devices (OLEDs)

    NASA Astrophysics Data System (ADS)

    Li, Gang; Uhlhorn, Brian L.; Shinar, Joseph

    2000-03-01

    The 9.44 GHz X-band ELDMR and EDMR of [indium tin oxide (ITO)]/[triphenyl diamine (TPD)]/Alq_3/X/Al OLEDs, where the buffer layer X = Al_2O3 or CsF, is described. At room temperature, the OLEDs exhibit EL- and current (I)-quenching (i.e., negative) resonances with a full width at half maximum of 29 G at g = 2.0. With X = Al_2O3 the resonance amplitudes are ΔI_EL/I_EL = 1.4x10-3 and ΔI/I = 4x10-4; with X = CsF, they are 4x10-4 and 3x10-5, respectively, i.e., much weaker. In addition, the resonances weaken as the devices degrades in air. These results indicate that spin-dependent processes at the Alq_3/cathode interface affect carrier injection and the EL. This scenario contrasts that invoked by earlier studies on PPV-based OLEDs, in which the resonances were attributed to bulk processes.^1,2 *Ames Laboratory is operated by Iowa State University for the US Department of Energy under Contract W-7405-Eng-82. ^1L. S. Swanson et al., Phys. Rev. B 46, 15072 (1992). ^2N. C. Greenham et al., Phys. Rev. B 53, 13528 (1996).

  20. The impact of trough geometry on film shape. A theoretical study of droplets containing polymer, for P-OLED display applications.

    PubMed

    Eales, Adam D; Dartnell, Nick; Goddard, Simon; Routh, Alexander F

    2015-11-15

    For P-OLED display fabrication, it is important to control the final film shape, arising from drying of volatile droplets containing polymer. Due to peripheral pinning and subsequent outward capillary flow, a coffee-ring typically develops. This is inconvenient since a spatially uniform height, above the substrate, is required to ensure uniform current across the device. Typically the droplets are deposited inside a trough-like structure on the substrate. We present a thin-film lubrication model that tracks the drying dynamics through to the final film shape. The governing equations are derived and solved numerically. We investigate the effect of the trough's depth and the slope of the walls. Increasing the depth or the wall's gradient increases coffee-ring formation. This is due to an increase in horizontal velocity, caused by the substrate's shape as well as delayed gelation of the polymer. The latter allows the outward capillary flow to act for a longer time, before the height becomes fixed. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Sol-gel-deposited Sb-doped SnO2 as transparent anode for OLED: process, patterning, and hole injection characteristics

    NASA Astrophysics Data System (ADS)

    Vaufrey, David; Ben Khelifa, M.; Besland, Marie-Paule; Sandu, C.; Blanchin, Marie-Genevieve; Teodorescu, Valentin S.; Roger, Jean-Alain; Tardy, Jacques

    2002-02-01

    This paper reports on the potentialities of sol-gel deposited Sb doped SnO2(T)) as a new transparent conducting oxide (TCO) for anode in organic light emitting diodes (OLED). Multilayered films with transparency over 85% and resistivity lower than 5 103(Omega) -cm were obtained. Structural observations by Transmission Electron Microscopy (TEM) show that the films are nanocrystallized. Smaller and more uniform grains are obtained upon rapid thermal annealing. Atomic Force Microscopy (AFM) imaging shows the surface roughness does not exceed 20 A. TO films are very stable and cannot be chemically etched. Anode patterning by reactive ion etching (RIE) in a Methane- Hydrogen plasma has been experienced and is described. Typical etching around 250 A/min were obtained. TO/PEDOT/PVK/Al hole only diodes were realized to assess sol gel TO films as hole injection electrodes. Devices with threshold voltages of 6 volts were obtained. A comparison with ITO deposited by low temperature cathodic sputtering is given.

  2. Surface activity as a crucial factor of the biological actions of Ole e 1, the main aeroallergen of olive tree (Olea europaea) pollen.

    PubMed

    Lopez-Rodriguez, Juan Carlos; Barderas, Rodrigo; Echaide, Mercedes; Perez-Gil, Jesus; Villalba, Mayte; Batanero, Eva; Cruz, Antonio

    2016-10-10

    Aeroallergens are airborne substances -mainly proteins- capable of triggering Th2-immune responses in respiratory allergies. They enter into the body through the upper airways, reaching the mucosa afterwards. Mucosae lining at the luminal side consists of an epithelial barrier completely covered by mucus and pulmonary surfactant. Both, pulmonary surfactant and plasma membrane of the epithelial cells represent two physiological phospholipid-based barriers where allergens first impact before triggering their biological effects. The interaction of allergens with lipids at relevant physiological surfaces could promote structural changes on the molecule, resulting on a potential modification of its allergenic properties. In this work, we have firstly described the surface and phospholipid interaction capabilities of the clinically relevant aeroallergen Ole e 1, the main allergen of olive tree pollen. By using epifluorescence microscopy of Langmuir transferred films, we observed that lipid-packed ordered domains may function as a preferential location for allergen to accumulate at the air-liquid interface, an effect that is abolished in the presence of cholestenone. The possible implications of phospholipid-interfacial effects in the modification of allergen structural and functional properties will be discussed.

  3. Localization of transcripts corresponding to the major allergen from olive pollen (Ole e I) by electron microscopic non-radioactive in situ RT-PCR.

    PubMed

    Alché, J D; Castro, A J; Rodríguez-García, M I

    2002-01-01

    In situ reverse transcription-PCR of mRNAs corresponding to the olive major allergen (Ole e I) has been tested at the ultrastructural level in mature olive pollen. The transcripts were present in the cytoplasm of both the vegetative and the generative cells, frequently associated to ribosomes in the endoplasmic reticulum. No labeling was detected in the pollen wall, nor in vacuoles, lipid bodies, plastids or mitochondria. Localization of the major olive allergen at ultrastructural level showed the protein present mainly in the lumen of the endoplasmic reticulum vesicles or pockets scattered in the cytoplasm, and in the outer region of the pollen exine. The results confirm the rough endoplasmic reticulum as the cell system involved in both the synthesis and storage of this protein. This is the first report of in situ RT-PCR on plant material at the ultrastructural level. The method described for mRNA amplification and detection is confirmed as a valuable tool for studying gene expression in plant material.

  4. Correlation between airborne Olea europaea pollen concentrations and levels of the major allergen Ole e 1 in Córdoba, Spain, 2012-2014

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Galán, C.

    2016-12-01

    Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity.

  5. Study of structural and optical properties of ZnAlQ{sub 5} (zinc aluminum quinolate) organic phosphor for OLED applications

    SciTech Connect

    Nagpure, I. M. Painuly, Deepshikha; Rabanal, Maria Eugenia

    2016-05-06

    The various composition of ZnAlQ{sub 5} such as Zn{sub 1.5}A{sub 10.5}Q{sub 5}, Zn{sub 1}Al{sub 1}Q{sub 5}, Zn{sub 0.5}Al{sub 1.5}Q{sub 5} organic phosphors were prepared via simple cost effective co-precipitation method. The FTIR, SEM, photoluminescence analysis of the prepared phosphors were reported. ZnQ{sub 2} and AlQ{sub 3} were also prepared by similar method and their properties were compared with different composition of ZnAlQ{sub 5}. The structural elucidation in the form of stretching frequencies of chemical bonds of the prepared phosphor was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The stretching frequency analysis confirms the formation of prepared phosphor materials. The SEM analysis shows the surface morphological behavior of prepared phosphor materials. Greenish photoluminescence were observed at 505 to 510 nm for the different composition of ZnAlQ{sub 5},in which Zn{sub 1.5}Al{sub 0.5}Q{sub 5} shows maximum luminescence intensity at 505 nm. PL emission of ZnQ{sub 2} was observed at 515 nm, while for AlQ{sub 3} at 520 nm. The blue shift of 10 nm was observed in Zn{sub 1.5}A{sub 10.5}Q{sub 5} due to modification of energy level due to presence of Zn{sup 2+} and Al{sup 3+}. The enhancement in PL intensity was observed in Zn{sub 1.5}A{sub 10.5}Q{sub 5} compared to the other composition due to transfer of energy between Zn{sup 2+} and quinolate complex. Optical properties of the prepared materials were evaluated for possible applications in organic light emitting devices (OLED).

  6. The effect of substituted 1,2,4-triazole moiety on the emission, phosphorescent properties of the blue emitting heteroleptic iridium(III) complexes and the OLED performance: a theoretical study.

    PubMed

    Srivastava, Ruby; Joshi, Laxmikanth Rao

    2014-08-28

    A series of neutral heteroleptic mononuclear iridium(III) complexes was investigated using the density functional theory/time-dependent density functional theory approach to determine the effect of the substituted 1,2,4-triazole moiety on the electronic structures, emission, and phosphorescent properties and the organic light emitting diode (OLED) performance. The results reveal that substitution of the free position in the triazole ring by -PhOCH3 (2) provides a higher emission energy and a lower oscillator strength, leading to longer radiative lifetime values mainly due to the ligand-to-ligand charge transfer transition character. The evaluation, based on one-center spin-orbit coupling, results in higher kr values for the substituent -F5Ph (5) and a lower ΔE(S-T) value. Furthermore, we also investigated the performance of the OLED device, including the charge injection/transport/balance ability, increases in the Förster energy transfer rate and triplet exciton confinement for host and guest materials of blue emitting Ir(III) complexes. Finally, we hope that our investigations will help in the design of highly efficient phosphorescent materials.

  7. Active layer solution-processed NIR-OLEDs based on ternary erbium(III) complexes with 1,1,1-trifluoro-2,4-pentanedione and different N,N-donors.

    PubMed

    Martín-Ramos, P; Coya, C; Lavín, V; Martín, I R; Silva, M Ramos; Silva, P S Pereira; García-Vélez, M; Alvarez, A L; Martín-Gil, J

    2014-12-28

    Using a fluorinated 1,1,1-trifluoro-2,4-pentanedione (Htfac) ligand and either 2,2'-bipyridine (bipy), bathophenanthroline (bath) or 5-nitro-1,10-phenanthroline (5NO2phen) as an ancillary ligand, three new ternary erbium(iii) octacoordinated complexes have been synthesized. The single crystal structures of the new complexes (namely [Er(tfac)3(bipy)], [Er(tfac)3(bath)] and [Er(tfac)3(5NO2phen)]) have been determined and their properties have been investigated by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and thermodynamic analysis. After ligand-mediated excitation of these complexes in the UV, they all show the characteristic near-infrared (NIR) luminescence of the corresponding Er(3+) ion at 1532 nm. The same emission in the C-band transmission window can also be obtained from the solution-processed organic light-emitting diodes (OLEDs) with structure: glass/ITO/PEDOT:PSS/[Er(tfac)3(N,N-donor)]/Ca/Al. In spite of the fact that the photoluminescence intensity of [Er(tfac)3(5NO2phen)] is stronger than those of [Er(tfac)3(bipy)] and [Er(tfac)3(bath)], the best electroluminescence results correspond to the OLED based on the [Er(tfac)3(bath)] complex, as a consequence of the superior electron transport capabilities of bathophenanthroline.

  8. Long-term efficacy and safety of α1 proteinase inhibitor treatment for emphysema caused by severe α1 antitrypsin deficiency: an open-label extension trial (RAPID-OLE).

    PubMed

    McElvaney, Noel G; Burdon, Jonathan; Holmes, Mark; Glanville, Allan; Wark, Peter A B; Thompson, Philip J; Hernandez, Paul; Chlumsky, Jan; Teschler, Helmut; Ficker, Joachim H; Seersholm, Niels; Altraja, Alan; Mäkitaro, Riitta; Chorostowska-Wynimko, Joanna; Sanak, Marek; Stoicescu, Paul I; Piitulainen, Eeva; Vit, Oliver; Wencker, Marion; Tortorici, Michael A; Fries, Michael; Edelman, Jonathan M; Chapman, Kenneth R

    2017-01-01

    Purified α1 proteinase inhibitor (A1PI) slowed emphysema progression in patients with severe α1 antitrypsin deficiency in a randomised controlled trial (RAPID-RCT), which was followed by an open-label extension trial (RAPID-OLE). The aim was to investigate the prolonged treatment effect of A1PI on the progression of emphysema as assessed by the loss of lung density in relation to RAPID-RCT. Patients who had received either A1PI treatment (Zemaira or Respreeza; early-start group) or placebo (delayed-start group) in the RAPID-RCT trial were included in this 2-year open-label extension trial (RAPID-OLE). Patients from 22 hospitals in 11 countries outside of the USA received 60 mg/kg per week A1PI. The primary endpoint was annual rate of adjusted 15th percentile lung density loss measured using CT in the intention-to-treat population with a mixed-effects regression model. This trial is registered with ClinicalTrials.gov, number NCT00670007. Between March 1, 2006, and Oct 13, 2010, 140 patients from RAPID-RCT entered RAPID-OLE: 76 from the early-start group and 64 from the delayed-start group. Between day 1 and month 24 (RAPID-RCT), the rate of lung density loss in RAPID-OLE patients was lower in the early-start group (-1·51 g/L per year [SE 0·25] at total lung capacity [TLC]; -1·55 g/L per year [0·24] at TLC plus functional residual capacity [FRC]; and -1·60 g/L per year [0·26] at FRC) than in the delayed-start group (-2·26 g/L per year [0·27] at TLC; -2·16 g/L per year [0·26] at TLC plus FRC, and -2·05 g/L per year [0·28] at FRC). Between months 24 and 48, the rate of lung density loss was reduced in delayed-start patients (from -2·26 g/L per year to -1·26 g/L per year), but no significant difference was seen in the rate in early-start patients during this time period (-1·51 g/L per year to -1·63 g/L per year), thus in early-start patients the efficacy was sustained to month 48. RAPID-OLE supports the continued efficacy of A1PI in slowing disease

  9. OLED devices with internal outcoupling

    DOEpatents

    Chichak, Kelly Scott; Liu, Jie Jerry; Shiang, Joseph John; Natarajan, Arunkumar; Heller, Christian Maria Anton

    2017-07-18

    Optoelectronic devices with enhanced internal outcoupling include a substrate, an anode, a cathode, an electroluminescent layer, and electron transporting layer comprising a fluoro compound of formula I (Ar.sup.2).sub.n--Ar.sup.1--(Ar.sup.2).sub.n I wherein Ar.sup.1 is C.sub.5-C.sub.40 aryl, C.sub.5-C.sub.40 substituted aryl, C.sub.5-C.sub.40 heteroaryl, or C.sub.5-C.sub.40 substituted heteroaryl; Ar.sup.2 is, independently at each occurrence, fluoro- or fluoroalkyl-substituted C.sub.5-40 heteroaryl; and n is 1, 2, or 3.

  10. OLED devices with internal outcoupling

    DOEpatents

    Liu, Jr., Jie Jerry; Sista, Srinivas Prasad; Shi, Xiaolei; Zhao, Ri-An; Chichak, Kelly Scott; Youmans, Jeffrey Michael; Janora, Kevin Henry; Turner, Larry Gene

    2016-12-06

    Optoelectronic devices with enhanced internal outcoupling include a substrate, an anode, a cathode, an electroluminescent layer, and an electron transporting layer comprising inorganic nanoparticles dispersed in an organic matrix.

  11. OLED devices with internal outcoupling

    DOEpatents

    Liu, Jie Jerry; Sista, Srinivas Prasad; Shi, Xiaolei; Zhao, Ri-An; Chichak, Kelly Scott; Youmans, Jeffrey Michael; Janora, Kevin Henry; Turner, Larry Gene

    2015-03-03

    Optoelectronic devices that have enhanced internal outcoupling are disclosed. The devices include a substrate, an anode, a cathode, an electroluminescent layer, and a hole injecting layer. The hole injecting layer includes inorganic nanoparticles that have a bimodal particle size distribution and which are dispersed in an organic matrix.

  12. Grupos españoles de cálculos ab initio de moléculas de interés astrofísico

    NASA Astrophysics Data System (ADS)

    Yáñez, M.

    grupos españoles han llevado, y siguen llevando a cabo, sobre sistemas débilmente enlazados, como complejos de Van der Waals o complejos por enlace de hidrógeno, que sin duda juegan un papel importante tanto en medios atmosféricos como interestelares.

  13. A theoretical study on tuning the electronic structures and photophysical properties of newly designed platinum(II) complexes by adding substituents on functionalized ligands as highly efficient OLED emitters.

    PubMed

    Zhang, Luqiong; Tian, Li; Li, Ming; He, Rongxing; Shen, Wei

    2014-05-07

    By imitating FIrpic, seven new platinum(II) complexes with pic (pic = picolinate) ligand have been designed to be guest materials by means of adding different substituents to functionalized ligands (ppy and fpy, ppy = phenylpyridyl-N,C and fpy = 2-(9',9'-diethyl-9H-fluorenyl)pyridyl-N,C). In order to reveal their molecular structures, photophysical properties and structure-property relationships with typical host materials, an in-depth theoretical investigation was performed via quantum chemical calculations. The electronic structures and photophysical properties of these complexes were investigated by density functional theory (DFT) and time-dependent density functional theory (TDDFT) using the B3LYP functional with LANL2DZ and 6-31G* basis sets. It turns out that electronic structures and photophysical properties can be tuned by substituent modifications on functionalized ligands. This work highlights that the match between guest materials and host materials in typical OLED structures can be weighed by the energy levels of the HOMO and LUMO and the adiabatic triplet energy of each complex. Also, a combined analysis of electronic structures, host-guest match, reorganization energies (λ) and triplet exciton generation fraction (χ(T)) is helpful in exploring triplet emitters with high phosphorescence efficiency in OLEDs, which is an interesting and creative aspect of this work. Thereinto, λ reveals the capability of carrier transport and the balance between holes and electrons, whilst structural parameters and d-orbital splittings show that those complexes that have strong electron-withdrawing and electron-donating groups are nonemissive. Consequently, complexes 3-7 can be better triplet emitters than FIrpic. Moreover, the emission colors could be predicted by the 0-0 transition energy (E(0-0)) instead of the triplet vertical transition energy (E(vert)). Accordingly, complexes 3, 4 and 6 would be efficient phosphorescent materials with different predicted

  14. Detection of genome donor species of neglected tetraploid crop Vigna reflexo-pilosa (créole bean), and genetic structure of diploid species based on newly developed EST-SSR markers from azuki bean (Vigna angularis).

    PubMed

    Chankaew, Sompong; Isemura, Takehisa; Isobe, Sachiko; Kaga, Akito; Tomooka, Norihiko; Somta, Prakit; Hirakawa, Hideki; Shirasawa, Kenta; Vaughan, Duncan A; Srinives, Peerasak

    2014-01-01

    Vigna reflexo-pilosa, which includes a neglected crop, is the only one tetraploid species in genus Vigna. The ancestral species that make up this allotetraploid species have not conclusively been identified, although previous studies suggested that a donor genome of V. reflexo-pilosa is V. trinervia. In this study, 1,429 azuki bean EST-SSR markers were developed of which 38 EST-SSR primer pairs that amplified one product in diploid species and two discrete products in tetraploid species were selected to analyze 268 accessions from eight taxa of seven Asian Vigna species including V. reflexo-pilosa var. glabra, V. reflexo-pilosa var. reflexo-pilosa, V. exilis, V. hirtella, V. minima, V. radiata var. sublobata, V. tenuicaulis and V. trinervia to identify genome donor of V. reflexo-pilosa. Since both diploid and tetraploid species were analyzed and each SSR primer pair detected two loci in the tetraploid species, we separated genomes of the tetraploid species into two different diploid types, viz. A and B. In total, 445 alleles were detected by 38 EST-SSR markers. The highest gene diversity was observed in V. hirtella. By assigning the discrete PCR products of V. reflexo-pilosa into two distinguished genomes, we were able to identify the two genome donor parents of créole bean. Phylogenetic and principal coordinate analyses suggested that V. hirtella is a species complex and may be composed of at least three distinct taxa. Both analyses also clearly demonstrated that V. trinervia and one taxon of V. hirtella are the genome donors of V. reflexo-pilosa. Gene diversity indicates that the evolution rate of EST-SSRs on genome B of créole bean might be faster than that on genome A. Species relationship among the Vigna species in relation to genetic data, morphology and geographical distribution are presented.

  15. A new class of sky-blue-emitting Ir(III) phosphors assembled using fluorine-free pyridyl pyrimidine cyclometalates: application toward high-performance sky-blue- and white-emitting OLEDs.

    PubMed

    Chang, Chih-Hao; Wu, Zih-Jyun; Chiu, Chuan-Hao; Liang, Yi-Hu; Tsai, Yu-Shan; Liao, Jia-Ling; Chi, Yun; Hsieh, Hsi-Ying; Kuo, Ting-Yi; Lee, Gene-Hsiang; Pan, Hsiao-An; Chou, Pi-Tai; Lin, Jin-Sheng; Tseng, Meu-Rurng

    2013-08-14

    Two pyrimidine chelates with the pyridin-2-yl group residing at either the 5- or 4-positions are synthesized. These chelates are then utilized in synthesizing of a new class of heteroleptic Ir(III) metal complexes, namely [Ir(b5ppm)2(fppz)] (1), [Ir(b5bpm)2(fppz)] (2), [Ir(b4bpm)2(fppz)] (3), and [Ir(b5bpm)(fppz)2] (4), for which the abbreviations b5ppm, b5bpm, b4bpm, and fppz represent chelates derived from 2-t-butyl-5-(pyridin-2-yl)pyrimidine, 2-t-butyl-5-(4-t-butylpyridin-2-yl)pyrimidine, 2-t-butyl-4-(4-t-butylpyridin-2-yl)pyrimidine, and 3-trifluoromethyl-5-(pyridin-2-yl) pyrazole, respectively. The single crystal X-ray structural analyses were executed on 1 to reveal their coordination arrangement around the Ir(III) metal element. The 5-substituted pyrimidine complexes 1, 2, and 4 exhibited the first emission peak wavelength (λmax) located in the range 452-457 nm with high quantum yields, whereas the emission of 3 with 4-substituted pyrimidine was red-shifted substantially to longer wavelength with λmax = 535 nm. These photophysical properties were discussed under the basis of computational approaches, particularly the relationship between emission color and the relative position of nitrogen atoms of pyrimidine fragment. For application, organic light-emitting diodes (OLEDs) were also fabricated using 2 and 4 as dopants, attaining the peak external quantum, luminance, and power efficiencies of 17.9% (38.0 cd/A and 35.8 lm/W) and 15.8% (30.6 cd/A and 24.8 lm/W), respectively. Combining sky blue-emitting 2 and red-emitting [Os(bpftz)2(PPh2Me)2] (5), the phosphorescent white OLEDs were demonstrated with stable pure-white emission at CIE coordinate of (0.33, 0.34), and peak luminance efficiency of 35.3 cd/A, power efficiency of 30.4 lm/W, and external quantum efficiency up to 17.3%.

  16. Electroluminescence-detected magnetic resonance study of OLEDs containing a mixed N,N'-diphenyl-N,N'-bis(1-naphthylphenyl)-1,1'-biphenyl-4,4'-diamine (NPB)/tris(quinolinolate) Al (Alq3) layer

    NASA Astrophysics Data System (ADS)

    Hellerich, Emily; Chen, Ying; Cai, Min; Shinar, Joseph

    2009-08-01

    The electroluminescence (EL)-detected magnetic resonance (ELDMR) of abrupt junction and mixed layer N,N'-diphenyl-N,N'-bis(1-naphthylphenyl)-1,1'-biphenyl-4,4'-diamine (NPB) / tris(quinolinolate) Al (Alq3) OLEDs was measured at room temperature and at 20K, at current densities 0.83 <= J <= 83 mA/cm2. The abrupt junction and mixed layer devices were indium tin oxide (ITO) / 5 nm copper phthalocyanine (CuPc) / 50 nm NPB / 40 nm Alq3 / 1 nm CsF / Al, and ITO / 5 nm CuPc / 40 nm NPB / 20 nm 1:1 NPB:Alq3 / 30 nm Alq3 / 1 nm CsF / Al, respectively. As expected, the devices exhibited a positive (EL-enhancing) spin 1/2 resonance at T = 20 K and a negative (ELquenching) spin 1/2 resonance at room temperature. It was found that the positive and negative resonance was stronger in the abrupt junction and in the mixed layer devices, respectively. The results are discussed in relation to the mechanisms responsible for these resonances, namely reduced quenching of singlet excitons by polarons and triplet excitons, and enhanced quenching by trions, respectively.

  17. Computational insights into the photophysical and electroluminescence properties of homoleptic fac-Ir(C^N)3 complexes employing different phenyl-derivative-featuring phenylimidazole-based ligands for promising phosphors in OLEDs.

    PubMed

    Li, Jieqiong; Wang, Li; Sun, Kenan; Zhang, Jinglai

    2016-02-21

    The electronic structures and photophysical properties of three homoleptic iridium(iii) complexes IrL3 with C^N ligands, including 2a (L = 1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole), 5a (L = 1-(2,6-dimethylphenyl)-2-phenyl-1H-imidazole), and 6a (L = 1-(3,5-diisopropylbiphenyl-4-yl)-2-phenyl-1H-imidazole), are investigated by means of the density functional method. Furthermore, seven new complexes are theoretically designed, including 1a (L = 1,2-diphenyl-1H-imidazole), 3a (L = 1-(2,6-dimethoxyphenyl)-2-phenyl-1H-imidazol), 4a (L = 2-(2-phenyl-1H-imidazol-1-yl)isophthalaldehyde), 1b (L = 2-(biphenyl-3-yl)-1H-imidazole), 2b (L = 2-(2',6'-diisopropylbiphenyl-3-yl)-1H-imidazole), 3b (L = 2-(2',6'-dimethoxybiphenyl-3-yl)-1H-imidazole), and 4b (L = 3'-(1H-imidazol-2-yl)biphenyl-2,6-dicarbaldehyde), to explore the influence of different substituents and different substituted positions on the electronic structures, phosphorescence properties, and organic light-emitting diode (OLED) performance. The HOMO-LUMO energy gap is greatly decreased by introduction of the -CHO group into the phenyl ring (4a and 4b see -sketched structures for all the investigated Ir(iii) complexes). As a result, their absorption and emission spectra present red-shifting leading them to be potential red-emitting phosphors. Other complexes are all blue-emitting materials, indicating that the effect of the substituted position on the emitting color is negligible. However, the addition of the substituent on the para-position of the phenyl ring in the phenylimidazole ligand would increase the quantum yield and electroluminescence (EL) performance compared with that on the imidazole ring.

  18. Post-polymerization C-H Borylation of Donor-Acceptor Materials Gives Highly Efficient Solid State Near-Infrared Emitters for Near-IR-OLEDs and Effective Biological Imaging.

    PubMed

    Crossley, Daniel L; Urbano, Laura; Neumann, Robert; Bourke, Struan; Jones, Jennifer; Dailey, Lea Ann; Green, Mark; Humphries, Martin J; King, Simon M; Turner, Michael L; Ingleson, Michael J

    2017-08-30

    Post-polymerization modification of the donor-acceptor polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole), PF8-BT, by electrophilic C-H borylation is a simple method to introduce controllable quantities of near-infrared (near-IR) emitting chromophore units into the backbone of a conjugated polymer. The highly stable borylated unit possesses a significantly lower LUMO energy than the pristine polymer resulting in a reduction in the band gap of the polymer by up to 0.63 eV and a red shift in emission of more than 150 nm. Extensively borylated polymers absorb strongly in the deep red/near-IR and are highly emissive in the near-IR region of the spectrum in solution and solid state. Photoluminescence quantum yield (PLQY) values are extremely high in the solid state for materials with emission maxima ≥ 700 nm with PLQY values of 44% at 700 nm and 11% at 757 nm for PF8-BT with different borylation levels. This high brightness enables efficient solution processed near-IR emitting OLEDs to be fabricated and highly emissive borylated polymer loaded conjugated polymer nanoparticles (CPNPs) to be prepared. The latter are bright, photostable, low toxicity bioimaging agents that in phantom mouse studies show higher signal to background ratios for emission at 820 nm than the ubiquitous near-IR emissive bioimaging agent indocyanine green. This methodology represents a general approach for the post-polymerization functionalization of donor-acceptor polymers to reduce the band gap as confirmed by the C-H borylation of poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2c,2cc-diyl) (PF8TBT) resulting in a red shift in emission of >150 nm, thereby shifting the emission maximum to 810 nm.

  19. 'Now we have to use the skills we have developed in cell physiological studies to attack the most crucial problems in pancreatic pathology': an interview with Ole H. Petersen, Medical Research Council Professor of Physiology, University of Liverpool, UK. [Interview by Martín E Fernández-Zapico].

    PubMed

    Petersen, Ole H

    2009-01-01

    Dr. Ole Petersen is one of the world's leading physiologists working on signal-transduction mechanisms in pancreatic acinar cells. He discovered local apical Ca(2+) signals as important regulators of acinar secretion. His work has been widely recognized, most importantly by his election as Fellow of The Royal Society in 2000 and more recently last year, when Queen Elizabeth II appointed him Commander of the Order of the British Empire (CBE) for 'Services to Science'. In this interview for Pancreatology, Dr. Petersen shares his life experiences as an innovative investigator of exocrine pancreatic function.

  20. Increasing Union Safety at Ole Miss.

    ERIC Educational Resources Information Center

    Hodge, Eldrid; Elmore, David

    1999-01-01

    Discusses the inclusion of a police substation in the student union of the University of Mississippi and its positive impact on administrators and students. The importance of having visible security and how it was designed into the facility are discussed; and the desired goals, shared by Union staff and the university police, that drove the design…

  1. Integrated fuses for OLED lighting device

    DOEpatents

    Pschenitzka, Florian

    2007-07-10

    An embodiment of the present invention pertains to an electroluminescent lighting device for area illumination. The lighting device is fault tolerant due, in part, to the patterning of one or both of the electrodes into strips, and each of one or more of these strips has a fuse formed on it. The fuses are integrated on the substrate. By using the integrated fuses, the number of external contacts that are used is minimized. The fuse material is deposited using one of the deposition techniques that is used to deposit the thin layers of the electroluminescent lighting device.

  2. Conjugated Triphenylene Polymers for Blue OLED Devices.

    PubMed

    Saleh, Moussa; Park, Young-Seo; Baumgarten, Martin; Kim, Jang-Joo; Müllen, Klaus

    2009-07-16

    Three polytriphenylene derivatives with phenyl and alkyl groups as side chains have been tested as blue light emitters. The best performance in terms of turn-on voltage and luminance efficiencies was obtained for poly(2-heptyl-3-(4-octylphenyl)-1,4-diphenyl-6,11-triphenylenyl-1,4-benzene) (1), which was additionally blended with an electron-transporting and a hole-injection material in the device, and had an onset of 4.6 V and reached 0.73 cd · A(-1) . Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Low-power SXGA active matrix OLED

    NASA Astrophysics Data System (ADS)

    Wacyk, Ihor; Prache, Olivier; Ghosh, Amal

    2009-05-01

    This paper presents the design and first evaluation of a full-color 1280×3×1024 pixel, active matrix organic light emitting diode (AMOLED) microdisplay that operates at a low power of 200mW under typical operating conditions of 35fL, and offers a precision 30-bit RGB digital interface in a compact size (0.78-inch diagonal active area). The new system architecture developed by eMagin for the SXGA microdisplay, based on a separate FPGA driver and AMOLED display chip, offers several benefits, including better power efficiency, cost-effectiveness, more features for improved performance, and increased system flexibility.

  4. Ultrabright fluorescent OLEDS using triplet sinks

    DOEpatents

    Zhang, Yifan; Forrest, Stephen R; Thompson, Mark

    2013-06-04

    A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer further comprises an organic host compound, an organic emitting compound capable of fluorescent emission at room temperature, and an organic dopant compound. The triplet energy of the dopant compound is lower than the triplet energy of the host compound. The dopant compound does not strongly absorb the fluorescent emission of the emitting compound.

  5. Extended OLED operational lifetime through phosphorescent dopant profile management

    DOEpatents

    Forrest, Stephen R.; Zhang, Yifan

    2017-05-30

    This disclosure relates, at least in part, an organic light emitting device, which in some embodiments comprises an anode; a cathode; a first emissive layer disposed between the anode and the cathode, the first emissive layer comprising an electron transporting compound and a phosphorescent emissive dopant compound; and wherein the phosphorescent emissive dopant compound has a concentration gradient, in the emissive layer, which varies from the cathode side of the first emissive layer to the anode side of the emissive layer.

  6. Polyelectrolyte/Graphene Oxide Barrier Film for Flexible OLED.

    PubMed

    Yang, Seung-Yeol; Park, Jongwhan; Kim, Yong-Seog

    2015-10-01

    Ultra-thin flexible nano-composite barrier layer consists of graphene oxide and polyelectrolyte was prepared using the layer-by-layer processing method. Microstructures of the barrier layer was optimized via modifying coating conditions and inducing chemical reactions. Although the barrier layer consists of hydrophilic polyelectrolyte was not effective in blocking the water vapor permeation, the chemical reduction of graphene oxide as well as conversion of polyelectrolyte to hydrophobic nature were very effective in reducing the permeation.

  7. White OLED with a single-component europium complex.

    PubMed

    Law, Ga-Lai; Wong, Ka-Leung; Tam, Hoi-Lam; Cheah, Kok-Wai; Wong, Wing-Tak

    2009-11-16

    A new direction for white organic light-emitting devices is shown, fabricated from a novel europium complex; this single component contains a double emission center of bluish-green and red, combined to a give a pure white emission (CIE x = 0.34 and y = 0.35).

  8. In the Bullring with a Foreign Language--Ole!

    ERIC Educational Resources Information Center

    Colbert, Ron

    2009-01-01

    With the rapid onset of globalization and increasing demand from business, government, and schools for fluency in another language, the author decided to learn Spanish. Driven by a desire to acquire functional language abilities in Spanish, he has embarked on this "better late than never" opportunity to learn the language, and in this…

  9. Fabrication of Transparent CNT Films for OLED Application

    DTIC Science & Technology

    2010-02-04

    coating resulted in SWCNT films with uniform sheet resistance and visible-light transmittance. With the control of the spin - coating conditions we...We optimized the process to prepare SWCNT solutions with the good degree of dispersion of individually isolated SWCNTs. The thin-film casting by spin

  10. In the Bullring with a Foreign Language--Ole!

    ERIC Educational Resources Information Center

    Colbert, Ron

    2009-01-01

    With the rapid onset of globalization and increasing demand from business, government, and schools for fluency in another language, the author decided to learn Spanish. Driven by a desire to acquire functional language abilities in Spanish, he has embarked on this "better late than never" opportunity to learn the language, and in this…

  11. Ole Roemer and the Light-Time Effect

    NASA Astrophysics Data System (ADS)

    Sterken, C.

    2005-07-01

    We discuss the observational background of Roemer's remarkable hypothesis that the velocity of light is finite. The outcome of the joint efforts of a highly-skilled instrumentalist and a team of surveyors driven to produce accurate maps and technically supported by the revolutionary advancements in horology, illustrates the synergy between the accuracy of the O and the C terms in the O-C concept which led to one of the most fundamental discoveries of the Renaissance.

  12. Electroluminescence of Zinc Complexes in Various OLED Structures

    NASA Astrophysics Data System (ADS)

    Odod, A. V.; Nikonova, E. N.; Nikonov, S. Yu.; Kopylova, T. N.; Kaplunov, M. G.; Krasnikova, S. S.; Nikitenko, S. L.; Yakushchenko, I. K.

    2017-05-01

    Results of spectral-luminescent and electroluminescent studies of organic semiconductor zinc complexes in light-emitting diode devices are presented. A displacement of the electroluminescence band maximum toward longer wavelengths with structure complication is shown. Devices based on zinc metal organic complexes have low threshold voltage (from 2.5 V) and brightness above 100 cd/m2.

  13. High efficiency fluorescent white OLEDs based on DOPPP

    NASA Astrophysics Data System (ADS)

    Zhang, Gang; Chen, Chen; Lang, Jihui; Zhao, Lina; Jiang, Wenlong

    2017-08-01

    The white organic light-emitting devices (WOLED) with the structures of ITO/m-MTDATA (10 nm)/NPB (30 nm)/Rubrene (0.2 nm)/DOPPP (x nm)/TAz (10 nm)/Alq3 (30 nm)/LiF (0.5 nm)/Al and ITO/NPB (30 nm)/DPAVBi:Rubrene (2 wt.%, 20 nm)/ DOPPP (x nm)/TAZ (10 nm)/Alq3 (30 nm)/LiF (0.5 nm)/Al (100 nm) have been fabricated by the vacuum thermal evaporation method. The results show that the chroma of the non-doped device is the best and the color coordinates are in the range of white light. The maximum luminance is 12,750 cd/m2 and the maximum current efficiency is 8.55 cd/A. The doped device A has the maximum luminance (16,570 cd/m2), when the thickness of blue layer DOPPP is 25 nm, and the doped device B achieves the highest efficiency (10.47 cd/A), when the thickness of DOPPP is 15 nm. All the performances of the doped devices are better than the non-doped one. The results demonstrate that the doped structures can realize the energy transfer and then improve the performance of the device effectively.

  14. Cyclometalated NCN platinum(II) acetylide complexes - Synthesis, photophysics and OLEDs fabrication

    NASA Astrophysics Data System (ADS)

    Szafraniec-Gorol, Grazyna; Slodek, Aneta; Schab-Balcerzak, Ewa; Grucela, Marzena; Siwy, Mariola; Filapek, Michal; Matussek, Marek; Zych, Dawid; Mackowski, Sebastian; Buczynska, Dorota; Grzelak, Justyna; Erfurt, Karol; Chrobok, Anna; Krompiec, Stanislaw

    2016-12-01

    The novel cyclometalated NCN platinum(II) acetylide complexes were synthesized. As precursors of acetylide ligands were used 9,9-dibutyl-2-ethynylfluorene, 9-butyl-3-ethynylcarbazole, and 5-ethynyl-2,2‧-bithiophene, whereas 1,3-di(2-pirydyl)benzene derivatives were cyclometalating NCN ligands. Variable character of ligands allowed to prepare a series of novel platinum(II) complexes, which showed light emission in a wide wavelength range from 410 to 625 nm. The optical and electrochemical properties of new complexes were examined and compared with theoretical DFT calculations. Complexes containing fluorenyl and carbazyl motif were used as emitters in an organic light-emitting diodes. The applicability of these Pt(II) complexes for electroluminescence was examined.

  15. Using Guest-Host Interactions To Optimize the Efficiency of TADF OLEDs.

    PubMed

    Dos Santos, Paloma L; Ward, Jonathan S; Bryce, Martin R; Monkman, Andrew P

    2016-09-01

    We show that the emitter and host combination must be optimized to minimize the reverse intersystem crossing (rISC) barrier and maximize thermally activated delayed fluorescence (TADF). The blue TADF emitter, 2,7-bis(9,9-dimethyl-acridin-10-yl)-9,9-dimethylthioxanthene-S,S-dioxide (DDMA-TXO2), has strong TADF character due to efficient charge transfer (CT) state formation. By combining DDMA-TXO2 with a host of correct polarity (DPEPO) that relaxes the CT manifolds' energy to become resonant with the lowest-energy local triplet state of DDMA-TXO2, the emitter and host combination produce a minimum rISC barrier (ΔEST), which maximizes TADF efficiency. We show that the sensitivity of these splittings is highly dependent on emitter environment and must be carefully tuned to optimize device performance. Devices utilizing DDMA-TXO2 in the DPEPO host show blue electroluminescence (EL), with commission internationale de l'éclairage (CIE) chromaticity coordinates of CIE (0.16, 0.24), with a maximum external quantum efficiency of 22.4%. This high device performance is a direct consequence of optimizing the TADF efficiency by this "host tuning".

  16. Salt Power: Is Neptune's Ole Salt a Tiger in the Tank?

    ERIC Educational Resources Information Center

    Wick, Gerry Shishin

    1979-01-01

    Discussed is the utilization of salinity-gradient energy as a potential source of power. Detailed are the scientific principles, potential sources, latest research, and environmental effects associated with this alternative energy source. The future prospects are addressed. (BT)

  17. Electro-active polymers containing pendent 2,7-diarylfluorene fragments as materials for OLEDs

    SciTech Connect

    Krucaite, G. Tavgeniene, D.; Peciulyte, L.; Buika, G.; Grigalevicius, S.; Liu, L.; Zhang, B.; Xie, Z.

    2016-05-18

    Poly[2-phenyl-7-(4-vinylphenyl)-9,9-diethylfluorene)], poly[2-(1-naphtyl)-7-(4-vinylphenyl)-9,9-diethylfluorene)] and poly[2-(4-biphenyl)-7-(4-vinylphenyl)-9,9-diethylfluorene)] were synthesized and characterized by NMR spectroscopy, elemental analysis and gel permeation chromatography. The derivatives represent materials of high thermal stability with initial thermal destruction temperatures from 390°C to 400 °C. The glass transition temperatures of the amorphous materials were 182 °C, 151 °C and 159 °C respectively. Hole-transporting properties of the polymeric materials were tested in the structures of organic light emitting diodes with Alq{sub 3} as the green emitter and electron transporting material. The device containing hole-transporting layers of polymer with 2-(4-biphenyl)-7-(4-vinylphenyl)-9,9-diethylfluorene moieties exhibited the best overall performance with turn on voltage of 3.6 V, a maximum photometric efficiency of 3.1 cd/A and maximum brightness of about 5300 cd/m{sup 2}.

  18. Ambipolar Phosphine Derivatives to Attain True Blue OLEDs with 6.5% EQE.

    PubMed

    Kondrasenko, Ilya; Tsai, Zheng-Hua; Chung, Kun-You; Chen, Yi-Ting; Ershova, Yana Yu; Doménech-Carbó, Antonio; Hung, Wen-Yi; Chou, Pi-Tai; Karttunen, Antti J; Koshevoy, Igor O

    2016-05-04

    A family of new branched phosphine derivatives {Ph2N-(C6H4)n-}3P → E (E = O 1-3, n = 1-3; E = S 4-6, n = 1-3; E = Se 7-9, n = 1-3; E = AuC6F5 4-6, n = 1-3), which are the donor-acceptor type molecules, exhibit efficient deep blue room temperature fluorescence (λem = 403-483 nm in CH2Cl2 solution, λem = 400-469 nm in the solid state). Fine tuning the emission characteristics can be achieved varying the length of aromatic oligophenylene bridge -(C6H4)n-. The pyramidal geometry of central R3P → E fragment on the one hand disrupts π-conjugation between the branches to preserve blue luminescence and high triplet energy, while on the other hand provides amorphous materials to prevent excimer formation and fluorescence self-quenching. Hence, compounds 2, 3, 5, and 12 were used as emitters to fabricate nondoped and doped electroluminescent devices. The luminophore 2 (E = O, n = 2) demonstrates excellently balanced bipolar charge transport and good nondoped device performance with a maximum external quantum efficiency (EQEmax) of 3.3% at 250 cd/m(2) and Commission International de L'Eclairage (CIE) coordinates of (0.15, 0.08). The doped device of 3 (E = O, n = 3) shows higher efficiency (EQEmax of 6.5, 6.0 at 100 cd/m(2)) and high color purity with CIE (0.15, 0.06) that matches the HDTV standard blue. The time-resolved electroluminescence measurement indicates that high efficiency of the device can be attributed to the triplet-triplet annihilation to enhance generation of singlet excitons.

  19. Studies on the photodegradation of red, green and blue phosphorescent OLED emitters.

    PubMed

    Schmidbauer, Susanna; Hohenleutner, Andreas; König, Burkhard

    2013-01-01

    The photodegradation behavior of four well-established iridium emitters was investigated. Irradiation of the samples in different solvents and under atmospheric as well as inert conditions helped to identify several pathways that can contribute to the deterioration of these compounds. Degradation via singlet oxygen or the excited states of the emitters as well as the detrimental influence of halogenated solvents are discussed for the different investigated iridium complexes. Some of the resulting degradation products could be identified by using LC-MS or other analytical techniques. The results show how even small structural changes can have a huge influence on rate and mechanism of the photodegradation. The observations from this study may help to better understand degradation processes occurring during the handling of the materials, but also during device processing and operation.

  20. Molecular Engineering of Host Materials for Blue Phosphorescent OLEDs: Past, Present and Future

    SciTech Connect

    Cosimbescu, Lelia; Koech, Phillip K.; Polikarpov, Evgueni; Swensen, James S.; Von Ruden, Amber L.; Rainbolt, James E.; Padmaperuma, Asanga B.

    2010-04-15

    We report molecular design considerations for blue phosphorescent host materials, as well as propose design rules necessary to build ambipolar hosts and thus reach charge balance in a device. Our beginning developments are presented followed by the evolution of the original design to our state-of-the-art, with the help of computational modeling.

  1. Hole transport in triphenylamine based OLED devices: from theoretical modeling to properties prediction.

    PubMed

    Cias, Pawel; Slugovc, Christian; Gescheidt, Georg

    2011-12-22

    For the series of para-substituted triphenylamines, optimized geometries, HOMO and LUMO energy levels, ionization potentials Ip, reorganization energies for hole transport λ(+), and frontier orbital contours have been calculated by means of ab initio computations. Relationships between them and the Hammett parameter are presented. According to calculations, electron releasing substituents increase the HOMO and LUMO energies of TPA, while electron withdrawing ones decrease it. This behavior is reflected in subsequent decreasing and increasing of ionization potentials of substituted TPAs. Calculations show that there exists also a strong substituent effect on the reorganization energy λ(+), which is a dominating factor of hole mobility. It is concluded that proper tuning of the HOMO and LUMO levels (and, as a result, ionization potential, Ip) and reorganization energy λ(+) (consequently, hole mobility) of the triphenylamine can be done by alteration of the TPA electronic structure by an appropriate substitution. It is demonstrated that the proper adjustment of the HOMO levels of HTM facilitates the reduction of an energy barrier at the interface of ITO/HTL and HTL/EL and ensure the high hole injection and hole transport rate. On the other hand, appropriate adjustment of the LUMO level prevents an electron leak from the EL into the HTM layer. Results of these calculations can be useful in the process of designing new HTM materials of desired properties (high efficiency, stability, and durability).

  2. Ab initio studies of the optoelectronic properties of biphenyl derivatives in OLEDs

    NASA Astrophysics Data System (ADS)

    Hashemi, Hossein; Bregman, Avi; Jung, Jaehun; Kwon, Minsang; Kim, Jinsang; Kieffer, John; Kieffer Group Team; Kim Group Team

    The influence of molecular conformation on electron relaxation and photophysical properties of a series of biphenyl derivatives have been investigated using density functional theory (DFT) and time-dependent DFT(TDDFT). The calculated absorption and emission properties of the series as well as phosphorescence quantum yield are in good agreement with the available experimental data. The spin orbit coupling values and the S --> T intersystem-crossing matrix elements and crossing rate constants are also explored as a function of the twist angle between the rings. The T --> S0 radiative and non-radiative transition rates are calculated and discussed for each member of the series. In addition, the T --> S0 radiative transition rate constant is calculated for twisted biphenyls and compared to those for planar molecules. Acknowledge support from: National Science Foundation, Grant No. DMR-1435965.

  3. Salt Power: Is Neptune's Ole Salt a Tiger in the Tank?

    ERIC Educational Resources Information Center

    Wick, Gerry Shishin

    1979-01-01

    Discussed is the utilization of salinity-gradient energy as a potential source of power. Detailed are the scientific principles, potential sources, latest research, and environmental effects associated with this alternative energy source. The future prospects are addressed. (BT)

  4. "A'ole" Drugs! Cultural Practices and Drug Resistance of Rural Hawai'ian Youths

    ERIC Educational Resources Information Center

    Po'A-Kekuawela, Ka'Ohinani; Okamoto, Scott K.; Nebre, La Risa H.; Helm, Susana; Chin, Coralee I. H.

    2009-01-01

    This qualitative study examined how Native Hawai'ian youths from rural communities utilized cultural practices to promote drug resistance and/or abstinence. Forty-seven students from five different middle schools participated in gender-specific focus groups that focused on the cultural and environmental contexts of drug use for Native Hawai'ian…

  5. Diboron complexes with bis-spiro structures as high-performance blue emitters for OLEDs.

    PubMed

    Zhang, Zhenyu; Zhang, Zuolun; Ye, Kaiqi; Zhang, Jingying; Zhang, Hongyu; Wang, Yue

    2015-08-28

    To construct high-performance organoboron-based blue emitters for electroluminescent (EL) devices, two diboron complexes have been synthesized through the chelation of 2-(1-phenyl-1H-benzo[d]imidazole-2-yl)phenol or 2-(2-pyridyl)phenol ligands with both boron atoms of the 9,10-diboraanthracene group. These complexes exhibit bright blue emissions in solution and in solid films with fluorescence quantum yields over 0.42, which benefit from their bis-spiro structures. In addition, they possess high thermal decomposition (>410 °C) and glass transition (>163 °C) temperatures. Moreover, they are excellent ambipolar transporting materials with high and balanced mobilities (>10(-4) cm(2) V(-1) s(-1)) for holes and electrons. Due to these excellent properties, the EL devices adopting these complexes as non-doped emitting layers emit blue light and exhibit low turn-on voltages (<3.2 V), high luminance (up to 9041 cd m(-2)), as well as high current (up to 7.01 cd A(-1)) and power efficiencies (up to 7.58 lm W(-1)). To the best of our knowledge, these devices are so far the brightest and most efficient blue devices based on four-coordinate organoboron emitters.

  6. Device structure for OLED light device having multi element light extraction and luminescence conversion layer

    DOEpatents

    Antoniadis,; Homer, Krummacher [Mountain View, CA; Claus, Benjamin [Regensburg, DE

    2008-01-22

    An apparatus such as a light source has a multi-element light extraction and luminescence conversion layer disposed over a transparent layer of the light source and on the exterior of said light source. The multi-element light extraction and luminescence conversion layer includes a plurality of light extraction elements and a plurality of luminescence conversion elements. The light extraction elements diffuses the light from the light source while luminescence conversion elements absorbs a first spectrum of light from said light source and emits a second spectrum of light.

  7. OLED lighting devices having multi element light extraction and luminescence conversion layer

    DOEpatents

    Krummacher, Benjamin Claus; Antoniadis, Homer

    2010-11-16

    An apparatus such as a light source has a multi element light extraction and luminescence conversion layer disposed over a transparent layer of the light source and on the exterior of said light source. The multi-element light extraction and luminescence conversion layer includes a plurality of light extraction elements and a plurality of luminescence conversion elements. The light extraction elements diffuses the light from the light source while luminescence conversion elements absorbs a first spectrum of light from said light source and emits a second spectrum of light.

  8. 'The big ole gay express': sexual minority stigma, mobility and health in the small city.

    PubMed

    Keene, Danya E; Eldahan, Adam I; White Hughto, Jaclyn M; Pachankis, John E

    2017-03-01

    Recent research has examined how gay and bisexual men experience and navigate the variations in sexual minority stigma that exist across geographic contexts, with implications for their health. We extend this literature on stigma, mobility, and health by considering the unique and understudied setting of the small city. Drawing on semi-structured interviews (n = 29) conducted in two small US cities (New Haven and Hartford), we find that these small cities serve as both destinations and points of departure for gay and bisexual men in the context of stigma. New Haven and Hartford attracted gay and bisexual men from surrounding suburbs where sexual minority stigma was more prevalent and where there were fewer spaces and opportunities for gay life. Conversely, participants noted that these small cities did not contain the same identity affirming communities as urban gay enclaves, thus motivating movement from small cities to larger ones. Our data suggest these forms of mobility may mitigate stigma, but may also produce sexual health risks, thus drawing attention to small cities as uniquely important sites for HIV prevention. Furthermore, our analysis contributes to an understanding of how place, stigma and mobility can intersect to generate spatially distinct experiences of stigmatised identities and related health consequences.

  9. RETRACTED: Passivation properties of OLEDs with aluminum cathodes prepared by ion-beam-assisted deposition process

    NASA Astrophysics Data System (ADS)

    Jeong, Soon Moon; Koo, Won Hoi; Choi, Sang Hun; Jo, Sung Jin; Baik, Hong Koo; Lee, Seong Min

    2005-03-01

    This article has been retracted at the request of the Editor-in-Chief and Author. Please see http://www.elsevier.com/locate/withdrawalpolicy. Reason: This Applied Surface Science submission contained essentially identical data, graphs, analysis, and conclusions of other articles that the authors had submitted and published concurrently in several other journals without notifying Applied Surface Science or the other journals involved. This is a clear violation of the Applied Surface Science policy: “Submission of a manuscript implies it is not being simultaneously considered for publication elsewhere and that the authors have obtained the necessary authority for publication.” The authors have therefore been asked to submit a formal letter of retraction, which has been received by the editorial office of Applied Surface Science. In this letter the corresponding author, Prof. Hong Koo Baik, apologized for the duplicate publication and acknowledges his responsibility for this incident.

  10. Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

    PubMed Central

    2013-01-01

    Summary The photodegradation behavior of four well-established iridium emitters was investigated. Irradiation of the samples in different solvents and under atmospheric as well as inert conditions helped to identify several pathways that can contribute to the deterioration of these compounds. Degradation via singlet oxygen or the excited states of the emitters as well as the detrimental influence of halogenated solvents are discussed for the different investigated iridium complexes. Some of the resulting degradation products could be identified by using LC–MS or other analytical techniques. The results show how even small structural changes can have a huge influence on rate and mechanism of the photodegradation. The observations from this study may help to better understand degradation processes occurring during the handling of the materials, but also during device processing and operation. PMID:24204420

  11. Novel Bipolar Indole-Based Solution- Processed Host Material for Efficient Green and Red Phosphorescent OLEDs.

    PubMed

    Chen, Yi; Wei, Xiang; Cao, Jin; Huang, Jinhai; Gao, Lei; Zhang, Jianhua; Su, Jianhua; Tian, He

    2017-03-06

    A new bipolar host material 2-(2'-(5-(dibenzo[b,d]furan-4-yl)-1H-indol-1-yl) -[1,1'-biphenyl]-4-yl)-1-phenyl-1H-benzo[d]imidazole (INDY) has been designed and synthesized for solution-processed PHOLEDs. Hole-transporting indole conjugated dibenzofuran scaffold and electron-transporting benzimidazole unit were orthogonally connection of incorporated by a 2,4'-biphenyl bridge, which endows a balanced bipolar charge transfer distribution and appropriate triplet energy level(>2.6 eV). The twisted conformation of INDY also ensures good thermal/morphological stability with high Tg (148 ºC). The solution-processed green PHOLEDs achieved great device efficiencies with 27.33 cd/A and 12.26 lm/W at 7 V. Meanwhile, the red solution-processed PHOLEDs gained excellent performance with the maximum efficiencies of 17.20 cd/A, 9.82 lm/W and 12.61 %. In addition, all the red devices presented excellent color stability with the same CIE coordinate as (0.65, 0.35) under varying dopant contents and operating voltages.

  12. Fixing simple olecranon fractures with the Olecranon Osteotomy Nail (OleON).

    PubMed

    Nijs, S; Graeler, H; Bellemans, J

    2011-12-01

    Stable fixation of simple olecranon fractures or olecranon osteotomies in order to allow early functional treatment. Simple (non-comminuted) olecranon fractures and (Chevron) osteotomies of the olecranon. Comminuted fractures and fractures more than 40 mm distal than the tip of the olecranon are contraindications. Using a slightly curved posterior approach, the fracture is anatomically reduced. The fracture is temporary stabilized using K-wires. A guiding K-wire is positioned centrally in the medullary canal in the lateral projection. The medullary canal is reamed over the K-wire. The distal part of the nail is inserted and locked. The proximal part is inserted and screwed onto the distal part to compress the fracture. For osteotomies, the distal part is inserted and locked (using the same technique as described before) prior to performing the osteotomy. At the end of the surgery, the osteotomy is reduced, the proximal part is inserted, and the osteotomy is compressed. As the stability of this compressive osteosynthesis is very high, early post-operative mobilization is allowed. No immobilization is used. Depending on the soft tissue situation, active range of motion and passive stretching is initiated immediately postoperatively. Using this technique in 21 patients (mean age 42 years) with acute fractures or osteotomies, sound fracture healing was achieved in 19 of 21 patients. The active range of motion was 130.2° flexion, 10.6° extension deficit, and a normal pro-supination arch. In one patient, delayed union caused implant failure. In this patient, a surgical error jeopardized stability. In a second patient, a peri-implant fracture after adequate trauma made a change in therapy necessary.

  13. Polyethers with pendent phenylvinyl substituted carbazole rings as polymers for hole transporting layers of OLEDs

    NASA Astrophysics Data System (ADS)

    Griniene, R.; Liu, L.; Tavgeniene, D.; Sipaviciute, D.; Volyniuk, D.; Grazulevicius, J. V.; Xie, Z.; Zhang, B.; Leduskrasts, K.; Grigalevicius, S.

    2016-01-01

    Polyethers containing pendent 3-(2-phenylvinyl)carbazole moieties have been synthesized by the multi-step synthetic routes. Full characterization of their structures is presented. The polymers represent materials of high thermal stability with initial thermal degradation temperatures exceeding 370 °C. The glass transition temperatures of the amorphous materials were in the range of 56-658 °C. The electron photoemission spectra of thin layers of the polymers showed ionization potentials of about 5.6 eV. Hole-transporting properties of the polymeric materials were tested in the structures of organic light emitting diodes with Alq3 as the green emitter and electron transporting layer. The device containing hole-transporting layers of poly{9-[6-(3-methyloxetan-3-ylmethoxy)hexyl]-3-(2-phenylvinyl)carbazole} exhibited the best overall performance with a maximum photometric efficiency of about 4.0 cd/A and maximum brightness exceeding 6430 cd/m2.

  14. Meteoroid mayhem in Ole Virginny: source of the North American tektite strewn field

    USGS Publications Warehouse

    Poag, C.W.; Powars, D.S.; Poppe, L.J.; Mixon, R.B.

    1994-01-01

    New seismic reflection data from Chesapeake Bay reveal a buried, 85-km-wide, 1.5-2.0-km-deep, peak-ring impact crater, carved through upper Eocene to Lower Cretaceous sedimentary strata and into underlying pre-Mesozoic crystalline basement rocks. A polymictic, late Eocene impact breccia, composed mainly of locally derived sedimentary debris (determined from four continuous cores), surrounds and partly fills the crater. Structural and sedimentary characteristics of the Chesapeake Bay crater closely resemble those of the Miocene Ries peak-ring crater in southern Germany. It is speculated that the Chesapeake Bay crater is the source of the North American tektite strewn field. -Authors

  15. Meteoroid mayhem in Ole Virginny: Source of the North American tektite strewn field

    USGS Publications Warehouse

    Poag, C. Wylie; Powars, David S.; Poppe, Lawrence J.; Mixon, Robert B.

    1994-01-01

    New seismic reflection data from Chesapeake Bay reveal a buried, 85-km-wide, 1.5-2.0-km-deep, peak-ring impact crater, carved through upper Eocene to Lower Cretaceous sedimentary strata and into underlying pre-Mesozoic crystalline basement rocks. A polymictic, late Eocene impact breccia, composed mainly of locally derived sedimentary debris (determined from four continuous cores), surrounds and partly fills the crater. Structural and sedimentary characteristics of the Chesapeake Bay crater closely resemble those of the Miocene Ries peakring crater in southern Germany. We speculate that the Chesapeake Bay crater is the source of the North American tektite strewn field.

  16. Psychodiagnostic Properties of the Piotr Oles´ "Internal Dialogical Activity Scale"

    ERIC Educational Resources Information Center

    Astretsov, D. A.; Leontiev, D. A.

    2016-01-01

    The article discusses the concept of internal dialogue and how it is understood in various schools of psychological research, including both Russia and abroad. The authors briefly investigate how the concept was understood by Mikhail Bakhtin, Lev Vygotsky, G.M. Kuchinskii, and Hubert Hermans. The "Internal Dialogical Activity Scale"…

  17. Rømer [Römer, Roemer], Ole [Olaf] Christensen (1644-1710)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Born in Aarhus, Denmark, studied at the University of Copenhagen under Thomas and Erasmus Bartholin, who gave him TYCHO BRAHE's manuscripts to edit and his own daughter to wed. Rømer accompanied Bartholin and JEAN PICARD to Hven to measure the position of Tycho's observatory, the better to reduce Tycho's observations. He went on to the Paris Observatory where he made and used instruments for the ...

  18. Furan Is Superior to Thiophene: A Furan‐Cored AIEgen with Remarkable Chromism and OLED Performance

    PubMed Central

    Zhao, Zheng; Nie, Han; Ge, Congwu; Cai, Yuanjing; Xiong, Yu; Qi, Ji; Wu, Wenting; Kwok, Ryan T. K.; Gao, Xike; Qin, Anjun; Lam, Jacky W. Y.

    2017-01-01

    Furan‐cored AIEgen namely tetraphenylethylene‐furan (TPE‐F) is developed by diyne cyclization and its fluorescent and chemical properties are investigated and compared with its thiophene analogue. Results show that furan is superior to thiophene in terms of fluorescence, chromism, and charge transport. The mechanism of chromism of TPE‐F is investigated and its efficient solid‐state photoluminescence and good charge‐transporting property enable it to serve as light‐emitting material for the construction of electroluminescence devices with excellent performance. This work not only demonstrates an efficient strategy for constructing furan‐cored AIEgens but also indicates that they are promising as advanced optoelectronic materials. PMID:28852618

  19. Enabling a blue-hazard free general lighting based on candle light-style OLED.

    PubMed

    Jou, Jwo-Huei; Kumar, Sudhir; An, Chih-Chia; Singh, Meenu; Yu, Huei-Huan; Hsieh, Chun-Yu; Lin, You-Xing; Sung, Chao-Feng; Wang, Ching-Wu

    2015-06-01

    Increasing studies report blue light to possess a potential hazard to the retina of human eyes, secretion of melatonin and artworks. To devise a human- and artwork-friendly light source and to also trigger a "Lighting Renaissance", we demonstrate here how to enable a quality, blue-hazard free general lighting source on the basis of low color-temperature organic light emitting diodes. With the use of multiple candlelight complementary emitters, the sensationally warm candle light-style emission is proven to be also drivable by electricity. To be energy-saving, highly efficient candle-light emission is demanded. The device shows, at 100 cd m-2 for example, an efficacy of 85.4 lm W-1, an external quantum efficiency of 27.4%, with a 79 spectrum resemblance index and 2,279 K color temperature. The high efficiency may be attributed to the candlelight emitting dyes with a high quantum yield, and the host molecules facilitating an effective host-to-guest energy transfer, as well as effective carrier injection balance.

  20. High light-extracting efficiency for OLED directly fabricated on double-side nanotextured silica substrate.

    PubMed

    Luo, Yu; Wang, Li; Ding, Yucheng; Li, Long; Shi, Jinfeng

    2013-07-15

    One economical method for extracting the light loss from both the waveguide mode and substrate is demonstrated. Pillar arrays with different scales are created on the two sides of a silica substrate by inductively coupled plasma etching following a colloidal masking. The quasi-periodic Bragg scattering structure on a silica/ITO interface led to a two-fold current efficiency without introducing a spectral shift or directionality. Meanwhile, the subwavelength-scaled antireflection structure on a silica/air interface produced further increases in efficiency by 40%. The organic light-emitting device directly fabricated on the double-sided nanotextured silica substrate reached an overall enhancement factor of ~2.8 with the current efficiency.

  1. Power-constrained contrast enhancement algorithm using multiscale retinex for OLED display.

    PubMed

    Nam, Yeon-Oh; Choi, Dong-Yoon; Song, Byung Cheol

    2014-08-01

    This paper presents a power-constrained contrast enhancement algorithm for organic light-emitting diode display based on multiscale retinex (MSR). In general, MSR, which is the key component of the proposed algorithm, consists of power controllable log operation and subbandwise gain control. First, we decompose an input image to MSRs of different sub-bands, and compute a proper gain for each MSR. Second, we apply a coarse-to-fine power control mechanism, which recomputes the MSRs and gains. This step iterates until the target power saving is accurately accomplished. With video sequences, the contrast levels of adjacent images are determined consistently using temporal coherence in order to avoid flickering artifacts. Finally, we present several optimization skills for real-time processing. Experimental results show that the proposed algorithm provides better visual quality than previous methods, and a consistent power-saving ratio without flickering artifacts, even for video sequences.

  2. Frequency-Selective Photobleaching as a Route to Chromatic Control in Supramolecular OLED Devices.

    PubMed

    Tsai, Yu-Tang; Liu, Hsiang-Fang; Peng, Bo-Ji; Tseng, Kuo-Pi; Kuo, Ming-Cheng; Wong, Ken-Tsung; Wantz, Guillaume; Hirsch, Lionel; Raffy, Guillaume; Del Guerzo, Andre; Bassani, Dario M

    2017-10-03

    We report a series of molecules that spontaneously self-organize into small electroluminescent domains of sub-micrometer dimensions when dissolved in tetrahydrofuran. The self-assembled spherical aggregates have an average diameter of 300 nm and exhibit efficient energy transfer from the blue to the green or red component. The aggregates can be chromatically addressed or patterned by selective bleaching of the energy-acceptor component using a laser source. This allows the fabrication of electroluminescence devices by directly photopatterning the active layer without the need of additional steps. Submicron features (700 nm) can be achieved using a collimated light source.

  3. Furan Is Superior to Thiophene: A Furan-Cored AIEgen with Remarkable Chromism and OLED Performance.

    PubMed

    Zhao, Zheng; Nie, Han; Ge, Congwu; Cai, Yuanjing; Xiong, Yu; Qi, Ji; Wu, Wenting; Kwok, Ryan T K; Gao, Xike; Qin, Anjun; Lam, Jacky W Y; Tang, Ben Zhong

    2017-08-01

    Furan-cored AIEgen namely tetraphenylethylene-furan (TPE-F) is developed by diyne cyclization and its fluorescent and chemical properties are investigated and compared with its thiophene analogue. Results show that furan is superior to thiophene in terms of fluorescence, chromism, and charge transport. The mechanism of chromism of TPE-F is investigated and its efficient solid-state photoluminescence and good charge-transporting property enable it to serve as light-emitting material for the construction of electroluminescence devices with excellent performance. This work not only demonstrates an efficient strategy for constructing furan-cored AIEgens but also indicates that they are promising as advanced optoelectronic materials.

  4. Novel Br-DPQ blue light-emitting phosphors for OLED.

    PubMed

    Dahule, H K; Thejokalyani, N; Dhoble, S J

    2015-06-01

    A new series of blue light-emitting 2,4-diphenylquinoline (DPQ) substituted blue light-emitting organic phosphors namely, 2-(4-methoxy-phenyl)-4-phenyl-quinoline (OMe-DPQ), 2-(4-methyl-phenyl)-4-phenylquinoline (M-DPQ), and 2-(4-bromo-phenyl)-4-phenylquinoline (Br-DPQ) were synthesized by substituting methoxy, methyl and bromine at the 2-para position of DPQ, respectively by Friedländer condensation of 2-aminobenzophenone and corresponding acetophenone. The synthesized phosphors were characterized by different techniques, e.g., Fourier transform infra-red (FTIR), differential scanning calorimeter (DSC), UV-visible absorption and photoluminescence spectra. FTIR spectra confirms the presence of chemical groups such as C=O, NH, or OH in all the three synthesized chromophores. DSC studies show that these complexes have good thermal stability. Although they are low-molecular-weight organic compounds, they have the potential to improve the stability and operating lifetime of a device made out of these complexes. The synthesized polymeric compounds demonstrate a bright emission in the blue region in the wavelength range of 405-450 nm in solid state. Thus the attachment of methyl, methoxy and bromine substituents to the diphenyl quinoline ring in these phosphors results in colour tuning of the phosphorescence. An electroluminescence (EL) cell of Br-DPQ phosphor was made and its EL behaviour was studied. A brightness-voltage characteristics curve of Br-DPQ cell revealed that EL begins at 400 V and then the brightness increases exponentially with applied AC voltage, while current-voltage (I-V) characteristics revealed that the turn on voltage of the fabricated EL cell was 11 V. Hence this phosphor can be used as a promising blue light material for electroluminescent devices. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Synthesis and properties of a solution-processable truxene derivative for OLED devices.

    PubMed

    Choi, Kyu Min; Kim, Kye-Young; Kim, Tae-Dong; Das, Rupasree Ragini; Choi, Byoung Ki; Park, Jong Jin; Kim, Jong-Min; Lee, Kwang-Sup

    2010-10-01

    A soluble truxene derivative (TR1) attached with triphenylamine at the peripheral position was designed and synthesized. The structure and purity of TR1 were carefully characterized by 1H NMR, UV/vis and photoluminescent spectroscopy, mass spectroscopy, and thermal analyses. It exhibited good solubility in common organic solvents and good film forming properties. The maximum absorption and emission peaks in THF solution were shown at 358 nm and 415 nm, respectively. Bright blue emission was observed in both solution and solid states under UV excitation. The fluorescent quantum efficiency was 0.46. The best luminous efficiency was found to be 3.65 cd/A with CIE coordinates of (0.163, 0.260) in electroluminescence devices.

  6. Cool white light-emitting three stack OLED structures for AMOLED display applications.

    PubMed

    Springer, Ramon; Kang, Byoung Yeop; Lampande, Raju; Ahn, Dae Hyun; Lenk, Simone; Reineke, Sebastian; Kwon, Jang Hyuk

    2016-11-28

    This paper demonstrates 2-stack and 3-stack white organic light-emitting diodes (WOLEDs) with fluorescent blue and phosphorescent yellow emissive units. The 2-stack and 3-stack WOLED comprises blue-yellow and blue-blue-yellow (blue-yellow-blue) combinations. The position of the yellow emitter and possible cavity lengths in different stack architectures are theoretically and experimentally investigated to reach Commission Internationale de L'Eclairage (CIE) coordinates of near (0.333/0.333). Here, a maximum external quantum efficiency (EQE) of 23.6% and current efficiency of 62.2 cd/A at 1000 cd/m2 as well as suitable CIE color coordinates of (0.335/0.313) for the blue-blue-yellow 3-stack hybrid WOLED structure is reported. In addition, the blue-yellow-blue 3-stack architecture exhibits an improved angular dependence compared to the blue-blue-yellow structure at a decreased EQE of 19.1%.

  7. A deep-blue OLED-based biochip for protein microarray fluorescence detection.

    PubMed

    Marcello, Alessandro; Sblattero, Daniele; Cioarec, Cristina; Maiuri, Paolo; Melpignano, Patrizia

    2013-08-15

    Integrated biochips exploit a multi-disciplinary approach to produce portable point-of-care medical diagnostic systems that uncouple diagnosis from centralized laboratories. These portable devices are cost effective and have several advantages including broader accessibility to health care worldwide. Fluorescence detection of a disease-specific probe excited by an optical source is one of the most diffused methods for quantitative analysis on biochips. Here we designed and characterized a miniaturized biochip based on a novel deep-blue organic light-emitting diode. The molecular design of the diode was optimized to excite a fluorophore-conjugated antibody and tested on a protein microarray configuration with good sensitivity and specificity. These findings will be instrumental for the development of next generation point-of-care biochips. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Performance analysis of multi-primary color display based on OLEDs/PLEDs

    NASA Astrophysics Data System (ADS)

    Xiong, Yan; Deng, Fei; Xu, Shan; Gao, Shufang

    2017-09-01

    A multi-primary color display, such as the six-primary color format, is a solution in expanding the color gamut of a full-color flat panel display. The performance of a multi-primary color display based on organic/polymer light-emitting diodes was analyzed in this study using the fitting curves of the characteristics of devices (i.e., current density, voltage, luminance). A white emitter was introduced into a six-primary color format to form a seven-primary color format that contributes to energy saving, and the ratio of power efficiency of a seven-primary color display to that of a six-primary color display would increase from 1.027 to 1.061 by using emitting diodes with different electroluminescent efficiencies. Different color matching schemes of the seven-primary color format display were compared in a uniform color space, and the scheme of the color reproduction did not significantly affect the display performance. Although seven- and six-primary color format displays benefit a full-color display with higher quality, they are less efficient than three-primary (i.e., red (R), green (G), and blue (B), RGB) and four-primary (i.e., RGB+white, RGBW) color format displays. For the seven-primary color formats considered in this study, the advantages of white-primary-added display with efficiently developed light-emitting devices were more evident than the format without a white primary.

  9. Physical and optical properties of DCJTB dye for OLED display applications: Experimental and theoretical investigation

    NASA Astrophysics Data System (ADS)

    Kurban, Mustafa; Gündüz, Bayram

    2017-06-01

    In this study, 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) was achieved using the experimental and theoretical studies. The electronic, optical and spectroscopic properties of DCJTB molecule were first investigated by performing experimental both solution and thin film techniques and then theoretical calculations. Theoretical results showed that one intense electronic transition is 505.26 nm a quite reasonable and agreement with the measured experimental data 505.00 and 503 nm with solution technique and film technique, respectively. Experimental and simple models were also taken into consideration to calculate the optical refractive index (n) of DCJTB molecule. The structural and electronic properties were next calculated using density functional theory (DFT) with B3LYP/6-311G (d, p) basis set. UV, FT-IR spectra characteristics and the electronic properties, such as frontier orbitals, and band gap energy (Eg) of DCJTB were also recorded time-dependent (TD) DFT approach. The theoretical Eg value were found to be 2.269 eV which is consistent with experimental results obtained from solution technique for THF solvent (2.155 eV) and literature (2.16 eV). The results herein obtained reveal that solution is simple, cost-efficient and safe for optoelectronic applications when compared with film technique.

  10. ‘A‘ole Drugs! Cultural Practices and Drug Resistance of Rural Hawaiian Youth

    PubMed Central

    PO‘A-KEKUAWELA, KA‘OHINANI; OKAMOTO, SCOTT K.; NEBRE, LA RISA H.; HELM, SUSANA; CHIN, CORALEE I. H.

    2009-01-01

    This qualitative study examined how Native Hawaiian youth from rural communities utilized cultural practices to promote drug resistance and/or abstinence. Forty-seven students from 5 different middle schools participated in gender specific focus groups that focused on the cultural and environmental contexts of drug use for Native Hawaiian youth. The findings described culturally specific activities that participants used in drug related problem situations. The findings also suggested that those youth with higher levels of enculturation were able to resist drugs more effectively than those youth who were disconnected from their culture. The implications of these findings for social work practice are discussed. PMID:20352019

  11. Computation of leading edge film cooling from a CONSOLE geometry (CONverging Slot hOLE)

    NASA Astrophysics Data System (ADS)

    Guelailia, A.; Khorsi, A.; Hamidou, M. K.

    2016-01-01

    The aim of this study is to investigate the effect of mass flow rate on film cooling effectiveness and heat transfer over a gas turbine rotor blade with three staggered rows of shower-head holes which are inclined at 30° to the spanwise direction, and are normal to the streamwise direction on the blade. To improve film cooling effectiveness, the standard cylindrical holes, located on the leading edge region, are replaced with the converging slot holes (console). The ANSYS CFX has been used for this computational simulation. The turbulence is approximated by a k-ɛ model. Detailed film effectiveness distributions are presented for different mass flow rate. The numerical results are compared with experimental data.

  12. Electroactive polymers containing 3-arylcarbazolyl units as hole transporting materials for OLEDs

    NASA Astrophysics Data System (ADS)

    Krucaite, G.; Liu, L.; Tavgeniene, D.; Peciulyte, L.; Grazulevicius, J. V.; Xie, Z.; Zhang, B.; Grigalevicius, S.

    2015-04-01

    Monomers and their polymers containing 3-arylcarbazolyl electrophores have been synthesized by the multi-step synthetic route. The materials were characterized by thermo-gravimetric analysis, differential scanning calorimetry and electron photoemission technique. The polymers represent materials of high thermal stability having initial thermal degradation temperatures in the range of 331-411 °C. The glass transition temperatures of the amorphous polymeric materials were in the rage of 148-175 °C. The electron photoemission spectra of thin layers of monomers showed ionization potentials in the range of 5.6-5.65 eV. Hole-transporting properties of the polymers were tested in the structures of organic light emitting diodes with Alq3 as the green emitter. The device containing hole-transporting layers of polyether with 3-naphthylcarbazolyl groups exhibited the best overall performance with a maximum current efficiency of 3.3 cd/A and maximum brightness of about 1000 cd/m2.

  13. Polymers containing isolated phenylvinyl substituted carbazole rings as electroactive materials for OLEDs

    NASA Astrophysics Data System (ADS)

    Griniene, Raimonda; Tavgeniene, Daiva; Grigalevičius, Saulius

    2016-05-01

    Polymers containing pendent 3-(2-phenylvinyl)carbazole moieties have been synthesized by the multi-step synthetic route. The polymers represent materials of high thermal stability with initial thermal degradation temperatures exceeding 370 °C. The glass transition temperatures of the amorphous materials were in the rage of 56-65 °C. The electron photoemission spectra of thin layers of the polymers showed ionization potentials of about 5.6 eV. Hole-transporting properties of the polymeric materials were tested in the structures of organic light emitting diodes with Alq 3 as the green emitter. The device containing hole-transporting layers of poly{9-[6-(3-methyloxetan-3-ylmethoxy)hexyl]-3-(2-phenylvinyl)carbazole} exhibited the best overall performance with a maximum photometric efficiency of about 4.0 cd/A and maximum brightness exceeding 6430 cd/m2.

  14. Polymers containing isolated phenylvinyl substituted carbazole rings as electroactive materials for OLEDs

    SciTech Connect

    Griniene, Raimonda; Tavgeniene, Daiva Grigalevičius, Saulius

    2016-05-18

    Polymers containing pendent 3-(2-phenylvinyl)carbazole moieties have been synthesized by the multi-step synthetic route. The polymers represent materials of high thermal stability with initial thermal degradation temperatures exceeding 370 °C. The glass transition temperatures of the amorphous materials were in the rage of 56–65 °C. The electron photoemission spectra of thin layers of the polymers showed ionization potentials of about 5.6 eV. Hole-transporting properties of the polymeric materials were tested in the structures of organic light emitting diodes with Alq 3 as the green emitter. The device containing hole-transporting layers of poly{9-[6-(3-methyloxetan-3-ylmethoxy)hexyl]-3-(2-phenylvinyl)carbazole} exhibited the best overall performance with a maximum photometric efficiency of about 4.0 cd/A and maximum brightness exceeding 6430 cd/m{sup 2}.

  15. Time Dependent Behavior of Light Emitting Polymers for Potential Individual Identify Friend or Foe (IIFF) Applications

    DTIC Science & Technology

    2007-12-01

    OLED DESIGN ........................................................ 9 B. ADD-VISION, INC. P- OLED ...6 Figure 6. Conventional p- OLED (From: [7...9 Figure 7. Add-Vision, Inc. Screen Printed P- OLED (From: [7]) .................................. 10 Figure 8

  16. A mechanically enhanced hybrid nano-stratified barrier with a defect suppression mechanism for highly reliable flexible OLEDs.

    PubMed

    Jeong, Eun Gyo; Kwon, Seonil; Han, Jun Hee; Im, Hyeon-Gyun; Bae, Byeong-Soo; Choi, Kyung Cheol

    2017-05-18

    Understanding the mechanical behaviors of encapsulation barriers under bending stress is important when fabricating flexible organic light-emitting diodes (FOLEDs). The enhanced mechanical characteristics of a nano-stratified barrier were analyzed based on a defect suppression mechanism, and then experimentally demonstrated. Following the Griffith model, naturally-occurring cracks, which were caused by Zn etching at the interface of the nano-stratified structure, can curb the propagation of defects. Cross-section images after bending tests provided remarkable evidence to support the existence of a defect suppression mechanism. Many visible cracks were found in a single Al2O3 layer, but not in the nano-stratified structure, due to the mechanism. The nano-stratified structure also enhanced the barrier's physical properties by changing the crystalline phase of ZnO. In addition, experimental results demonstrated the effect of the mechanism in various ways. The nano-stratified barrier maintained a low water vapor transmission rate after 1000 iterations of a 1 cm bending radius test. Using this mechanically enhanced hybrid nano-stratified barrier, FOLEDs were successfully encapsulated without losing mechanical or electrical performance. Finally, comparative lifetime measurements were conducted to determine reliability. After 2000 hours of constant current driving and 1000 iterations with a 1 cm bending radius, the FOLEDs retained 52.37% of their initial luminance, which is comparable to glass-lid encapsulation, with 55.96% retention. Herein, we report a mechanically enhanced encapsulation technology for FOLEDs using a nano-stratified structure with a defect suppression mechanism.

  17. ‘The big ole gay express’: sexual minority stigma, mobility and health in the small city

    PubMed Central

    Keene, Danya E.; Eldahan, Adam I.; White Hughto, Jaclyn M.; Pachankis, John E.

    2016-01-01

    Recent research has examined how gay and bisexual men experience and navigate the variations in sexual minority stigma that exist across geographic contexts, with implications for their health. We extend this literature on stigma, mobility, and health by considering the unique and understudied setting of the small city. Drawing on semi-structured interviews (n = 29) conducted in two small US cities (New Haven and Hartford), we find that these small cities serve as both destinations and points of departure for gay and bisexual men in the context of stigma. New Haven and Hartford attracted gay and bisexual men from surrounding suburbs where sexual minority stigma was more prevalent and where there were fewer spaces and opportunities for gay life. Conversely, participants noted that these small cities did not contain the same identity affirming communities as urban gay enclaves, thus motivating movement from small cities to larger ones. Our data suggest these forms of mobility may mitigate stigma, but may also produce sexual health risks, thus drawing attention to small cities as uniquely important sites for HIV prevention. Furthermore, our analysis contributes to an understanding of how place, stigma and mobility can intersect to generate spatially distinct experiences of stigmatised identities and related health consequences. PMID:27604293

  18. An Ambipolar BODIPY Derivative for a White Exciplex OLED and Cholesteric Liquid Crystal Laser toward Multifunctional Devices.

    PubMed

    Chapran, Marian; Angioni, Enrico; Findlay, Neil J; Breig, Benjamin; Cherpak, Vladyslav; Stakhira, Pavlo; Tuttle, Tell; Volyniuk, Dmytro; Grazulevicius, Juozas V; Nastishin, Yuriy A; Lavrentovich, Oleg D; Skabara, Peter J

    2017-02-08

    A new interface engineering method is demonstrated for the preparation of an efficient white organic light-emitting diode (WOLED) by embedding an ultrathin layer of the novel ambipolar red emissive compound 4,4-difluoro-2,6-di(4-hexylthiopen-2-yl)-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (bThBODIPY) in the exciplex formation region. The compound shows a hole and electron mobility of 3.3 × 10(-4) and 2 × 10(-4) cm(2) V(-1) s(-1), respectively, at electric fields higher than 5.3 × 10(5) V cm(-1). The resulting WOLED exhibited a maximum luminance of 6579 cd m(-2) with CIE 1931 color coordinates (0.39; 0.35). The bThBODIPY dye is also demonstrated to be an effective laser dye for a cholesteric liquid crystal (ChLC) laser. New construction of the ChLC laser, by which a flat capillary with an optically isotropic dye solution is sandwiched between two dye-free ChLC cells, provides photonic lasing at a wavelength well matched with that of a dye-doped planar ChLC cell.

  19. Ole Taeao Afua, the new morning: a qualitative investigation into Samoan perspectives on mental health and culturally appropriate services.

    PubMed

    Tamasese, Kiwi; Peteru, Carmel; Waldegrave, Charles; Bush, Allister

    2005-04-01

    The first objective was to develop a culturally appropriate research method to investigate Samoan perspectives on mental health issues. The second objective was to apply this to identify cultural values and understandings important in the care and treatment of Samoan people with mental health problems. Gender-specific focus groups consisting of Samoan elders and service providers were facilitated by Samoan researchers in the Samoan language. Systematic analysis of the transcripts, adapted to the cultural context, were conducted in Samoan and later translated into English. A culturally derived method, referred to as Fa'afaletui, reflecting Samoan communal values and familiar institutional structures within the community, allowed each focus group to come to a consensual view on issues discussed. The Samoan self was identified as an essential concept for understanding Samoan views of mental health. This self was described as a relational self and mental wellness as a state of relational harmony, where personal elements of spiritual, mental and physical are in balance. Mental ill health was sometimes linked to breaches of forbidden and sacred relationships, which could be addressed effectively only within protocols laid down in the culture. Additional stressors contributing to mental ill-health were identified as low income, unemployment, rising housing costs and the marginalization of Samoan cultural norms in New Zealand. Participants identified the need for a culturally based mental health service for Samoan people to address key cultural factors. The Fa'afaletui method is a new research method which is sensitive and responsive to Samoan cultural norms and is methodologically rigorous. Such an approach may be relevant for other Pacific Island cultures and other cultures, which have a strong emphasis on collectivity. The Samoan concept of self provides a theoretical foundation for understanding the mental health needs of Samoan people and a basis for developing appropriate services.

  20. Nickelocene-Precursor-Facilitated Fast Growth of Graphene/h-BN Vertical Heterostructures and Its Applications in OLEDs.

    PubMed

    Li, Qiucheng; Zhao, Zifeng; Yan, Baoming; Song, Xiuju; Zhang, Zhepeng; Li, Jia; Wu, Xiaosong; Bian, Zuqiang; Zou, Xiaolong; Zhang, Yanfeng; Liu, Zhongfan

    2017-08-01

    The direct growth of high-quality, large-area, uniform, vertically stacked Gr/h-BN heterostructures is of vital importance for applications in electronics and optoelectronics. However, the main challenge lies in the catalytically inert nature of the hexagonal boron nitride (h-BN) substrates, which usually afford a rather low decomposition rate of carbon precursors, and thus relatively low growth rate of graphene. Herein, a nickelocene-precursor-facilitated route is developed for the fast growth of Gr/h-BN vertical heterostructures on Cu foils, which shows much improved synthesis efficiency (8-10 times faster) and crystalline quality of graphene (large single-crystalline domain up to ≈20 µm). The key advantage of our synthetic route is the utilization of nickel atoms that are decomposed from nickelocene molecules as the gaseous catalyst, which can decrease the energy barrier for graphene growth and facilitate the decomposition of carbon sources, according to our density functional theory calculations. The high-quality Gr/h-BN stacks are proved to be perfect anode/protecting layers for high-performance organic light-emitting diode devices. In this regard, this work offers a brand-new route for the fast growth of Gr/h-BN heterostructures with practical scalability and high crystalline quality, thus should propel its wide applications in transparent electrodes, high-performance electronic devices, and energy harvesting/transition directions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Single-Shot ${\\text{T}}_{{2}}$ Mapping Through OverLapping-Echo Detachment (OLED) Planar Imaging.

    PubMed

    Cai, Congbo; Zeng, Yiqing; Zhuang, Yuchuan; Cai, Shuhui; Chen, Lin; Ding, Xinghao; Bao, Lijun; Zhong, Jianhui; Chen, Zhong

    2017-10-01

    Develop a reliable single-shot T2 mapping method with extra robustness to motion and the potential for real-time dynamic and quantitative MR imaging. A single-shot T2 mapping sequence was proposed based on spin-echo planar imaging acquisition scheme. Two overlapped echo signals with different T2 weighting were obtained simultaneously by using two small flip-angle excitation pulses and corresponding echo-shifting gradients. A detachment algorithm based on structure similarity constraint was proposed to separate the two echo signals. T2 mapping was obtained from the two separated echo signals. The robustness and efficiency of the method were demonstrated through simulation, phantom experiments, and human brain measurements. Reliable T2 mapping can be obtained within milliseconds even under continuous head motion. Reliable T2 mapping was achieved with a single shot for the first time. The proposed method will facilitate real-time dynamic and quantitative MR imaging.

  2. White OLED with high stability and low driving voltage based on a novel buffer layer MoOx

    NASA Astrophysics Data System (ADS)

    Jiang, Xue-Yin; Zhang, Zhi-Lin; Cao, Jin; Khan, M. A.; Khizar-ul-Haq; Zhu, Wen-Qing

    2007-09-01

    White organic light emitting diodes (WOLEDs) with copper phthalocyanine (CuPc), 4,4',4''-tris(N-3-methylphenyl-N-phenyl-amino) triphenylamine (m-MTDATA), tungsten oxide (WO3) and molybdenum oxide (MoOx) as buffer layers have been investigated. The MoOx based device shows superior performance with low driving voltage, high power efficiency and much longer lifetime than those with other buffer layers. For the Cell using MoOx as buffer layer and 4,7-diphenyl-1,10-phenanthroline (Bphen) as electron transporting layer (ETL), at the luminance of 1000 cd m-2, the driving voltage is 4.9 V, which is 4.2 V, 2 V and 0.7 V lower than that of the devices using CuPc (Cell-CuPc), m-MTDATA (Cell-m-MTDATA) and WO3 (Cell-WO3) as buffer layers, respectively. Its power efficiency is 7.67 Lm W-1, which is 2.37 times higher than that of Cell-CuPc and a little higher than that of Cell-m-MTDATA. The projected half-life under the initial luminance of 100 cd m-2 is 55 260 h, which is more than 4.6 times longer than that of Cell-m-MTDATA and Cell-CuPc. The superior performance of Cell-MoOx is attributed to its high hole injection ability and the stable interface between MoOx and organic material. The work function of MoOx has been measured by the contact potential difference method. The J-V curves of 'hole-only' devices indicate that a small hole injection barrier between MoOx/N,'-bis(naphthalene-1-y1)-N, N'-bis(phenyl)-benzidine (NPB) leads to a strong hole injection, resulting in a low driving voltage and a high stability.

  3. Properties of TCO anodes deposited by atmospheric pressure chemical vapor deposition and their application to OLED lighting

    NASA Astrophysics Data System (ADS)

    Korotkov, R. Y.

    2012-02-01

    Doped ZnO is one of the materials currently being considered in commercial optoelectronic applications as a potential indium tin oxide (ITO) replacement for the transparent conducting oxide (TCO). The properties of doped ZnO anodes prepared at Arkema Inc. are analyzed using spectroscopic ellipsometer (230 to 1700 nm) and Hall-effect. The modeling of the refractive indexes is conducted using a double oscillator model. The model parameters are tested on a double layer: undoped and doped structure deposited by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates. Excellent correlation between calculated and experimental parameters was obtained.

  4. Incorporation of spiroxanthene units in blue-emitting oligophenylene frameworks: a new molecular design for OLED applications.

    PubMed

    Poriel, Cyril; Cocherel, Nicolas; Rault-Berthelot, Joëlle; Vignau, Laurence; Jeannin, Olivier

    2011-11-04

    We report herein the incorporation of xanthenyl units into two extended π-conjugated phenylene systems, namely indenofluorene and pentaphenylene. Thus, dispiroxanthene-indenofluorene (DSX-IF) and dispiroxanthene-ladderpentaphenylene (DSX-LPP) have been designed and synthesized through short and efficient synthetic approaches. These two molecules possess a 3π-2-spiro architecture (3π-systems/2-spiro bridges), in which two xanthenyl cores are spirolinked to a π-conjugated backbone either indenofluorene for DSX-IF or pentaphenylene for DSX-LPP. The structural, electrochemical, and photophysical properties of these blue/violet emitters have been studied in detail and compared to those of their 'all carbon' analogues with spirofluorenyl cores instead of spiroxanthenyl cores, namely dispirofluorene-indenofluorene (DSF-IF) and dispirofluorene-ladderpentaphenylene (DSF-LPP), previously reported in the literature. Finally, the application of DSX-IF and DSX-LPP as new light-emitting materials in nondoped organic light emitting diodes is reported. A detailed optical study of the different electroluminescence spectra is notably presented, with an emphasis 1) on the origin of the low-energy emission band observed in the case of DSX-LPP and 2) on the unexpected optical contribution of the well-known hole-transporting-layer NPB (N,N'-di(naphtyl)-N,N'-diphenyl(1,1'-biphenyl)-4,4'-diamine). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Tetraphenylcyclopentadiene Derivatives: Aggregation-Induced Emission, Adjustable Luminescence from Green to Blue, Efficient Undoped OLED Performance and Good Mechanochromic Properties.

    PubMed

    Ruan, Zhijun; Li, Le; Wang, Can; Xie, Yujun; Hu, Quanyuan; Peng, Qian; Ye, Shanghui; Li, Qianqian; Li, Zhen

    2016-12-01

    Silole derivatives, the first reported and famous AIEgens, are a series of Si-containing conjugated rings with the σ*-π* conjugation, and this unique electronic structure imparts them high electron affinity and fast electron mobility, but not ideal blue luminogens due to their relatively long conjugation length. By replacing the Si atom with the C one, six new AIEgens without the σ*-π* conjugation effect are successfully synthesized based on a tetraphenylcyclopentadiene core. In addition to the sky-blue emission (λEL = 492 nm) with Lmax , ηC,max , and ηP,max up to 24 096 cd m(-2) , 6.80 cd A(-1) , and 4.07 lm W(-1) , respectively, the careful control of the conjugation degree by changing the linkage mode, results in the blue one (λEL = 440 nm) with relatively good performance (Lmax : 8721 cd m(-2) and ηC,max : 3.40 cd A(-1) ), indicating that the replacement of the Si atom by C one is an alternative design strategy to yield blue even deep-blue AIEgens with good device performance. Meanwhile, their reversible mechanochromic properties are realized with apparent fluorescence changes between deep-blue and green emissive colors, offering them additional promising applications in optoelectronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A Method for Reducing the Singlet-Triplet Energy Gaps of TADF Materials for Improving the Blue OLED Efficiency.

    PubMed

    Rajamalli, Pachaiyappan; Senthilkumar, Natarajan; Gandeepan, Parthasarathy; Ren-Wu, Chen-Cheng; Lin, Hao-Wu; Cheng, Chien-Hong

    2016-10-12

    We have successfully synthesized a series of blue thermally activated delayed fluorescence emitters, BPy-pC, BPy-pTC, BPy-p2C, and BPy-p3C, bearing a 4-benzoylpyridine core as the electron-accepting unit and carbazolyl, tert-butylcarbazolyl, dicarbazolyl, and tercarbazolyl groups as the electron-donating units, respectively. The density functional theory calculation shows that all of the compounds have their lowest unoccupied molecular orbitals on the benzoylpyridine moiety. However, the highest occupied molecular orbital (HOMO) of BPy-p3C is widely dispersed to the whole tercarbazolyl group, while the HOMOs of BPy-pC and BPy-pTC are mainly on the carbazolyl and extended to the phenyl ring. As a result, ΔEST is reduced from 0.29 eV for BPy-pC to 0.05 eV for BPy-p3C, and the organic light-emitting diodes using these materials as dopants emit blue light and their maximum external quantum efficiencies (EQEs) increase from 4.2% to 23.9% for BPy-pC and BPy-p3C, respectively. The EQE of the BPy-p3C-based device increases 2 times more than that of the BPy-pTC-based device without a significant change in the color coordinates.

  7. Significant color space blue-shift of green OLED emitter with sustaining lifetime and substantial efficiency enhancement

    NASA Astrophysics Data System (ADS)

    Li, Jung-Yu; Chen, Shih-Pu; Siao, Huei-Jhen; Wu, Jin-Han; Chen, Guan-Yu; Chen, Cheng-Chang; Ho, Shu-Yi; Lin, Yi-Ping; Hsu, Hong-Hui; Lin, Jin-Sheng; Jeng, Ming-Shan; Chen, Nai-Chuan; Zeng, Hui-Kai; Juang, Jenh-Yih

    2017-08-01

    In this study, we demonstrate that by embedding a plasmonic coupling metal layer beneath the active layer of an organic light-emitting diode, the resultant device is capable of inducing significant blue shifts in CIE color space coordinates of emitting light from the green emitting material without compromising the lifetime of the parent material. The implemented device consists of multilayers of organic emitting materials sandwiched by two thin metal layers to form a metal-dielectric-metal (MDM) cavity-like structure. The original green emission with CIE coordinates of (0.22, 0.56) was significantly color space blue-shifted to CIE coordinates of (0.10, 0.53). The MDM device exhibits an efficiency of 62 cd/A at a luminance of 1000 cd/m2, which represents a two-fold enhancement of current efficiency. Moreover, the spectral peak intensity is 4.3 times higher than that in a conventional device, which is much higher than that expected for an optical microcavity model, suggesting that the Purcell effect resulting from the coupling of surface plasmon waves may contribute to the extra enhancement of emission intensity.

  8. Cooking "shrimp à la créole": a pilot study of an ecological rehabilitation in semantic dementia.

    PubMed

    Bier, Nathalie; Macoir, Joël; Joubert, Sven; Bottari, Carolina; Chayer, Céline; Pigot, Hélène; Giroux, Sylvain

    2011-08-01

    New learning in semantic dementia (SD) seems to be tied to a specific temporal and spatial context. Thus, cognitive rehabilitation could capitalise upon preserved episodic memory and focus on everyday activities which, once learned, will have an impact in everyday life. This pilot study thus explores the effectiveness of an ecological approach in one patient suffering from SD. EC, a 68-year-old woman with SD, stopped cooking complex meals due to a substantial loss of knowledge related to all food types. The therapy consisted of preparing a target recipe. She was asked to generate semantic attributes of ingredients found in one target, one control and two no-therapy recipes. The number of recipes cooked by EC between therapy sessions was computed. She was also asked to prepare a generalisation recipe combining ingredients from the target and control recipes. EC's generated semantic attributes (GSA) of ingredients pertaining to the target and control recipes increased significantly (p < .001), compared to the no-therapy recipes (ps > .79). The proportion of meals cooked also increased significantly (p = .021). For the generalisation recipe, she could not succeed without assistance. Frequent food preparation may have provided EC with new memories about the context, usage and appearance of some concepts. These memories seem very context-bound, but EC nonetheless re-introduced some recipes into her day-to-day life. The impact of these results on the relationship between semantic, episodic and procedural memory is discussed, as well as the relevance of an ecological approach in SD.

  9. Electrophoretic technique with a thin electrochemical cell driving by light like a photoprinting process: for LED and OLED screening application

    NASA Astrophysics Data System (ADS)

    Shein, I. V.; Shmakov, S. L.

    2007-05-01

    A novel electrophoretic (EP) technique for depositing and patterning phosphors (or other powder components) is under development: EPD in a high viscous medium onto specific points on the conductive substrate.

  10. Report on the Utilization of the CAN/OLE Online Document Ordering System (CAN/DOC) in Interlibrary Loan Operations.

    ERIC Educational Resources Information Center

    Tallon, James

    The study reported was conducted at Concordia University after using the CAN/DOC ordering system to procure documents in the sciences directly from the Canada Institute for Scientific and Technical Information (CISTI) to assess the efficiency of interlibrary loan (ILL) procedures using this system. This study focuses on the relative turn-around…

  11. Molecular orientation, thermal behavior and density of electron and hole transport layers and the implication on device performance for OLEDs

    NASA Astrophysics Data System (ADS)

    Kearns, Kenneth L.; Na, Hong-Yeop; Froese, Robert D.; Mukhopadhyay, Sukrit; Woodward, Hunter; Welsh, Dean; De Vries, Timothy; Devore, David; Trefonas, Peter; Hong, Liang

    2014-10-01

    Recent progress has shown that molecular orientation in vapor-deposited glasses can affect device performance. The deposition process can result in films where the molecular axis of the glass material is preferentially ordered to lie parallel to the plane of the substrate. Here, materials made within Dow's Electronic Materials business showed enhanced performance when the orientation of the molecules, as measured by variable angle spectroscopic ellipsometry, was oriented in a more parallel fashion as compared to other materials. For one material, the anisotropic packing was observed in the as-deposited glass and was isotropic for solution-cast and annealed films. In addition, the density of an as-deposited N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine (NPD) film was 0.8% greater than what was realized from slowly cooling the supercooled liquid. This enhanced density indicated that vapor-deposited molecules were packing more closely in addition to being anisotropic. Finally, upon heating the NPD film into the supercooled liquid state, both the density and anisotropic packing of the as-deposited glass was lost.

  12. Novel Na(+) doped Alq3 hybrid materials for organic light-emitting diode (OLED) devices and flat panel displays.

    PubMed

    Bhagat, S A; Borghate, S V; Kalyani, N Thejo; Dhoble, S J

    2015-05-01

    Pure and Na(+) -doped Alq3 complexes were synthesized by a simple precipitation method at room temperature, maintaining a stoichiometric ratio. These complexes were characterized by X-ray diffraction, Fourier transform infrared (FTIR), UV/Vis absorption and photoluminescence (PL) spectra. The X-ray diffractogram exhibits well-resolved peaks, revealing the crystalline nature of the synthesized complexes, FTIR confirms the molecular structure and the completion of quinoline ring formation in the metal complex. UV/Vis absorption and PL spectra of sodium-doped Alq3 complexes exhibit high emission intensity in comparison with Alq3 phosphor, proving that when doped in Alq3 , Na(+) enhances PL emission intensity. The excitation spectra of the synthesized complexes lie in the range 242-457 nm when weak shoulders are also considered. Because the sharp excitation peak falls in the blue region of visible radiation, the complexes can be employed for blue chip excitation. The emission wavelength of all the synthesized complexes lies in the bluish green/green region ranging between 485 and 531 nm. The intensity of the emission wavelength was found to be elevated when Na(+) is doped into Alq3 . Because both the excitation and emission wavelengths fall in the visible region of electromagnetic radiation, these phosphors can also be employed to improve the power conversion efficiency of photovoltaic cells by using the solar spectral conversion principle. Thus, the synthesized phosphors can be used as bluish green/green light-emitting phosphors for organic light-emitting diodes, flat panel displays, solid-state lighting technology - a step towards the desire to reduce energy consumption and generate pollution free light. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Identification, Classification and Differential Expression of Oleosin Genes in Tung Tree (Vernicia fordii)

    PubMed Central

    Cao, Heping; Zhang, Lin; Tan, Xiaofeng; Long, Hongxu; Shockey, Jay M.

    2014-01-01

    Triacylglycerols (TAG) are the major molecules of energy storage in eukaryotes. TAG are packed in subcellular structures called oil bodies or lipid droplets. Oleosins (OLE) are the major proteins in plant oil bodies. Multiple isoforms of OLE are present in plants such as tung tree (Vernicia fordii), whose seeds are rich in novel TAG with a wide range of industrial applications. The objectives of this study were to identify OLE genes, classify OLE proteins and analyze OLE gene expression in tung trees. We identified five tung tree OLE genes coding for small hydrophobic proteins. Genome-wide phylogenetic analysis and multiple sequence alignment demonstrated that the five tung OLE genes represented the five OLE subfamilies and all contained the “proline knot” motif (PX5SPX3P) shared among 65 OLE from 19 tree species, including the sequenced genomes of Prunus persica (peach), Populus trichocarpa (poplar), Ricinus communis (castor bean), Theobroma cacao (cacao) and Vitis vinifera (grapevine). Tung OLE1, OLE2 and OLE3 belong to the S type and OLE4 and OLE5 belong to the SM type of Arabidopsis OLE. TaqMan and SYBR Green qPCR methods were used to study the differential expression of OLE genes in tung tree tissues. Expression results demonstrated that 1) All five OLE genes were expressed in developing tung seeds, leaves and flowers; 2) OLE mRNA levels were much higher in seeds than leaves or flowers; 3) OLE1, OLE2 and OLE3 genes were expressed in tung seeds at much higher levels than OLE4 and OLE5 genes; 4) OLE mRNA levels rapidly increased during seed development; and 5) OLE gene expression was well-coordinated with tung oil accumulation in the seeds. These results suggest that tung OLE genes 1–3 probably play major roles in tung oil accumulation and/or oil body development. Therefore, they might be preferred targets for tung oil engineering in transgenic plants. PMID:24516650

  14. Hidden Markov models used for the offline classification of EEG data.

    PubMed

    Obermaier, B; Guger, C; Pfurtscheller, G

    1999-06-01

    Hidden Markov models (HMM) are introduced for the offline classification of single-trail EEG data in a brain-computer-interface (BCI). The HMMs are used to classify Hjorth parameters calculated from bipolar EEG data, recorded during the imagination of a left or right hand movement. The effects of different types of HMMs on the recognition rate are discussed. Furthermore a comparison of the results achieved with the linear discriminant (LD) and the HMM, is presented.

  15. Electron-Rich 4-Substituted Spirobifluorenes: Toward a New Family of High Triplet Energy Host Materials for High-Efficiency Green and Sky Blue Phosphorescent OLEDs.

    PubMed

    Quinton, Cassandre; Thiery, Sébastien; Jeannin, Olivier; Tondelier, Denis; Geffroy, Bernard; Jacques, Emmanuel; Rault-Berthelot, Joëlle; Poriel, Cyril

    2017-02-22

    We report herein a detailed structure-properties relationship study of the first examples of electron-rich 4-substituted spirobifluorenes for organic electronic applications, namely, 4-phenyl-N-carbazole-spirobifluorene (4-PhCz-SBF) and 4-(3,4,5-trimethoxyphenyl)-spirobifluorene (4-Ph(OMe)3-SBF). The incorporation of the electron-rich moieties in the ortho position of the biphenyl linkage (position C4) induces unique properties, very different from those previously described in the literature for this family of semiconductors. Both dyes can be readily synthesized, possess high triplet energies and excellent thermal stability, and their HOMO energy levels are highly increased compared to those of other 4-substituted SBFs. We also provide in this work the first rationalization of the peculiar fluorescence of 4-substituted SBFs. Finally, the present dyes have been successfully incorporated as host in green and blue phosphorescent organic light-emitting diodes with high performance either for the green (EQE of 20.2%) or the blue color (EQE of 9.6%). These performances are, to the best of our knowledge, among the highest reported to date for 4-substituted SBF derivatives.

  16. The effect of substituted moiety on the optoelectronic and photophysical properties of tris (phenylbenzimidazolinato) Ir (III) carbene complexes and the OLED performance: a theoretical study

    NASA Astrophysics Data System (ADS)

    Srivastava, Ruby

    2015-06-01

    Density functional theory (DFT) and time-dependent density functional theory (TDDFT) are used to analyse theoretically the optoelectronic, photophysical properties and organic light-emitting diode performance of a series of fac-mer blue-emitting Iridium (III) carbene complexes. Swain-Lupton constant is used to discuss the substituents effect. 5d-orbital splitting and d-d* transitions are calculated to assess the efficiency of the studied complexes. The reorganisation energies (λ), transfer integrals, mobilities, radiative decay rate (kr), and triplet exciton generation fraction (χT) are also calculated. Due to the higher χT of these complexes, the formation of triplet exciton will be more and it will cause a faster intersystem crossing. Two host materials are proposed and host-guest match (Dexter-Förster energy) is also discussed. We hope that this unified work will surely help to design new blue-emitting phosphorescent materials in future.

  17. Donor–acceptor-structured 1,4-diazatriphenylene derivatives exhibiting thermally activated delayed fluorescence: design and synthesis, photophysical properties and OLED characteristics

    PubMed Central

    Takahashi, Takehiro; Shizu, Katsuyuki; Yasuda, Takuma; Togashi, Kazunori; Adachi, Chihaya

    2014-01-01

    A new series of luminescent 1,4-diazatriphenylene (ATP) derivatives with various peripheral donor units, including phenoxazine, 9,9-dimethylacridane and 3-(diphenylamino)carbazole, is synthesized and characterized as thermally activated delayed fluorescence (TADF) emitters. The influence of the donor substituents on the electronic and photophysical properties of the materials is investigated by theoretical calculations and experimental spectroscopic measurements. These ATP-based molecules with donor–acceptor–donor (D–A–D) structures can reduce the singlet–triplet energy gap (0.04–0.26 eV) upon chemical modification of the ATP core, and thus exhibit obvious TADF characteristics in solution and doped thin films. As a demonstration of the potential of these materials, organic light-emitting diodes containing the D–A–D-structured ATP derivatives as emitters are fabricated and tested. External electroluminescence quantum efficiencies above 12% and 8% for green- and sky-blue-emitting devices, respectively, are achieved. PMID:27877670

  18. Forward molecular design for highly efficient OLED emitters: a theoretical analysis of photophysical properties of platinum(II) complexes with N-heterocyclic carbene ligands.

    PubMed

    Wu, Yong; Wu, Shui-Xing; Li, Hai-Bin; Geng, Yun; Su, Zhong-Min

    2011-05-07

    The electronic structures and photophysical properties of eight Pt-complexes with different N-heterocyclic carbene ligands and potential to serve as light emitting diode materials were investigated by density functional theory and time-dependent density functional theory, employing the BP86 functional for geometry optimisations, SAOP potential for excited state calculations and all-electron TZ2P basis set throughout. Non-radiative and radiative decay rate constants were determined for each system through analyses of the geometric relaxations, d-orbital splitting and spin-orbit couplings at the optimised S(0) and T(1) geometries. Three Pt-systems bound to two N-heterocyclic carbenes were shown to be nonemissive, while a fourth was shown to be emissive from the T(1) excited state. Similar T(1)-initated emission was observed for three other Pt-systems investigated, each bound to four N-heterocyclic carbenes, while a fourth similarly tetra-ligated system showed T(2)-initation of emission. The results highlight the coupling of ligand-identity to photophysical properties and more importantly, the potential for rational optimisation and tuning of emission wavelengths and phosphorescent efficiencies. Encouragingly, two of the tetra-N-heterocyclic carbene ligated systems show strong potential to serve as highly-efficient blue and green light emitting materials, respectively.

  19. Synthesis and optoelectronic properties of symmetrical thiophene based 2,5-disubstiuted 1,3,4-oxadiazoles: highly fluorescent materials for OLED applications.

    PubMed

    Panchamukhi, Shridhar I; Belavagi, Ningaraddi; Rabinal, Mohammed Hussain; Khazi, Imitiyaz Ahmed

    2011-07-01

    Symmetrical 2,5-disubstituted thiophene derivatives containing 1,3,4-oxadiazole moiety bearing different aromatic substitutions were synthesized by employing convenient and simple synthetic protocols using thiophene-2,5,dicarboxylic acid as a starting material. The structures of these target molecules were established by their analytical and spectral data. The photophysical and electrochemical studies were carried out on these compounds and found that they exhibit good fluorescent properties with high quantum yield. © Springer Science+Business Media, LLC 2011

  20. 6-N,N-diphenylaminobenzofuran-derived pyran containing fluorescent dyes: a new class of high-brightness red-light-emitting dopants for OLED.

    PubMed

    Leung, Man-kit; Chang, Chin-Chuan; Wu, Meng-Hsiu; Chuang, Kai-Hsiang; Lee, Jiun-Haw; Shieh, Shwu-Ju; Lin, Shien-Chang; Chiu, Chi-Feng

    2006-06-08

    Dye-doped organic light-emitting diode of ITO/alpha-NPB (70 nm)/Bebq(2)-1 (7 nm)/BCP (5 nm)/Bebq(2) (33 nm)/LiF (1 nm)/Al (150 nm) shows red electroluminescence with the efficiency of 2.9 cd/A at 100 cd/m(2) and maximum brightness of 62000 cd/m(2). The physical organic aspects of the current-induced fluorescent quenching effect are discussed. [structure: see text