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Sample records for ole hjorth caspersen

  1. 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.

  2. OLED area illumination source

    DOEpatents

    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.

  3. 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.

  4. Release of OLe peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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. 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…

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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).

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  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. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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 .

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  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.

    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.

  3. ["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.

  4. 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).

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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%.

  13. 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.

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. [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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  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. '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.

  17. 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.

  18. Ultrabright fluorescent OLEDS using triplet sinks

    SciTech Connect

    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.

  19. 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.

  20. 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…

  1. 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

  2. Environmental Life Cycle Techniques for New Weapons Acquisition Systems

    DTIC Science & Technology

    2004-09-01

    in Steen (1999). Weighting is made through valuation on the five damage categories human health, ecosystem production capacity, abiotic stock...the willingness to pay to avoid changes, and is calculated as environmental load units (ELU). More information can be found in Steen (1999). 5.3...Bech P., Wenzel H., Caspersen N., Olsen S. I. (2001). Håndbog i miljøvurdering af produkter - en enkel metode. In Miljønyt Nr. 58 2001

  3. 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.

  4. 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.

  5. Device structure for OLED light device having multi element light extraction and luminescence conversion layer

    DOEpatents

    Antoniadis; Homer , Krummacher; Benjamin Claus

    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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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)

  11. 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 ...

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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".

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. ‘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

  3. 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.

  4. 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.

  5. 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…

  6. Investigation of the Representation of OLEs and Terrain Effects Within the Costal Zone in the EDMF Parameterization Scheme: An Airborne Doppler Wind Lidar Perspective

    DTIC Science & Technology

    2014-10-20

    Model q= [u, V, w, T]T To 1^* Nonlinear Landau Term; 0 + A2qo, Aq^o + 0 + A^Pii 0 + A^q^o 0+0 + A^qgQ (mean flow modification...are present, the EDMF model has no mechanism for parameterizing their non-gradient contribution to the PBL fluxes. Our strategy is to use the DWL...quasi-equilibrium state in which finite amplitude rolls are maintained in a slightly modified mean state. This mechanism is well-established in the

  7. 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

    EDMF) parameterization of turbulence and convective mixing in numerical models. The main focus was in using previously obtained Twin Otter Doppler...Mass Flux (EDMF) parameterization of turbulence and convective mixing in numerical models. As during the previous years, we have focused on using...expression that better represents the contributions of shear generated rolls as opposed to convective organization? In addition to the analysis of real TODWL

  8. Measurement of hyperfine fields and the Δg-effect in π-conjugated polymer-based OLEDs using multi-frequency electrically detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Joshi, Gajadhar; Malissa, Hans; Miller, Richard; Ogden, Lillie; Baird, Douglas; Jamali, Shirin; Kavand, Marzieh; Ambal, Kapil; van Tol, Johan; Lupton, John; Boehme, Christoph

    Magneto-opto-electronic properties of organic semiconductors, such as organic magnetoresistance or magneto-electroluminescence, are strongly influenced by the interplay of proton induced hyperfine fields to which charge carrier spins are coupled [Nguyen et al., Nat. Mater. 9, 345-352 (2010), McCamey et al. Phys. Rev. Lett. 104, 017601 (2010)]. In addition, the weak but non-negligible and highly inhomogeneously distributed spin-orbit effects caused by the material's structural disorder can affect spin-dependent processes. In order to quantitatively access and discriminate between these mechanisms, we investigate the inhomogeneous broadening of polaron spin-resonances using electrically detected magnetic resonance (EDMR) spectroscopy at various magnetic fields between 3mT and 12T. While random local hyperfine fields cause an external magnetic field-independent line broadening, spin-orbit contributions give rise to a distribution of the charge carrier g-factors. This Δg effect leads to a resonance line-width contribution that is proportional to the external magnetic field. We observe an EDMR line that is largely field-independent in the low-magnetic field, but shows substantial broadening of line shape at higher fields.

  9. Donor-acceptor-structured 1,4-diazatriphenylene derivatives exhibiting thermally activated delayed fluorescence: design and synthesis, photophysical properties and OLED characteristics

    NASA Astrophysics Data System (ADS)

    Takahashi, Takehiro; Shizu, Katsuyuki; Yasuda, Takuma; Togashi, Kazunori; Adachi, Chihaya

    2014-06-01

    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.

  10. Novel molecular host materials based on carbazole/PO hybrids with wide bandgap via unique linkages for solution-processed blue phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Ye, Hua; Zhou, Kaifeng; Wu, Hongyu; Chen, Kai; Xie, Gaozhan; Hu, Jingang; Yan, Guobing; Ma, Songhua; Su, Shi-Jian; Cao, Yong

    2016-10-01

    A series of novel molecules with wide bandgap based on electron-withdrawing diphenyl phosphine oxide units and electron-donating carbazolyl moieties through insulated unique linkages of flexible chains terminated by oxygen or sulfur atoms as solution-processable host materials were successfully synthesized for the first time, and their thermal, photophysical, and electrochemical properties were studied thoroughly. These materials possess high triplet energy levels (ET, 2.76-2.77 eV) due to the introduction of alkyl chain to interrupt the conjugation between electron-donor and electron-acceptor. Such high ET could effectively curb the energy from phosphorescent emitter transfer to the host molecules and thus assuring the emission of devices was all from the blue phosphorescent emitter iridium (III) bis [(4,6-difluorophenyl)-pyridinate-N,C2‧]picolinate (FIrpic). Among them, the solution-processed device based on CBCR6OPO without extra vacuum thermal-deposited hole-blocking layer and electron-transporting layer showed the highest maximum current efficiency (CEmax) of 4.16 cd/A. Moreover, the device presented small efficiency roll-off with current efficiency (CE) of 4.05 cd/A at high brightness up to 100 cd/m2. Our work suggests the potential applications of the solution-processable materials with wide bandgap in full-color flat-panel displays and organic lighting.

  11. Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs

    NASA Astrophysics Data System (ADS)

    Kumar, Naveen; Wilkinson, Taylor M.; Packard, Corinne E.; Kumar, Mukesh

    2016-06-01

    The development of efficient and reliable large-area flexible optoelectronic devices demands low surface roughness-low residual stress-high optoelectronic merit transparent conducting oxide (TCO) thin films. Here, we correlate surface roughness-residual stress-optoelectronic properties of sputtered amorphous indium zinc oxide (a-IZO) thin films using a statistical design of experiment (DOE) approach and find a common growth space to achieve a smooth surface in a stress-free and high optoelectronic merit a-IZO thin film. The sputtering power, growth pressure, oxygen partial pressure, and RF/(RF+DC) are varied in a two-level system with a full factorial design, and results are used to deconvolve the complex growth space, identifying significant control growth parameters and their possible interactions. The surface roughness of a-IZO thin film varies over 0.19 nm to 3.97 nm, which is not in line with the general assumption of low surface roughness in a-IZO thin films. The initial regression model and analysis of variance reveal no single optimum growth sub-space to achieve low surface roughness (≤0.5 nm), low residual stress (-1 to 0 GPa), and industrially acceptable electrical conductivity (>1000 S/cm) for a-IZO thin films. The extrapolation of growth parameters in light of the current results and previous knowledge leads to a new sub-space, resulting in a low residual stress of -0.52±0.04 GPa, a low surface roughness of 0.55±0.03 nm, and moderate electrical conductivity of 1962±3.84 S/cm in a-IZO thin films. These results demonstrate the utility of the DOE approach to multi-parameter optimization, which provides an important tool for the development of flexible TCOs for the next-generation flexible organic light emitting diodes applications.

  12. Design of low surface roughness-low residual stress-high optoelectronic merit a-IZO thin films for flexible OLEDs

    SciTech Connect

    Kumar, Naveen; Wilkinson, Taylor M.; Packard, Corinne E.; Kumar, Mukesh

    2016-06-08

    The development of efficient and reliable large-area flexible optoelectronic devices demands low surface roughness-low residual stress-high optoelectronic merit transparent conducting oxide (TCO) thin films. Here, we correlate surface roughness-residual stress-optoelectronic properties of sputtered amorphous indium zinc oxide (a-IZO) thin films using a statistical design of experiment (DOE) approach and find a common growth space to achieve a smooth surface in a stress-free and high optoelectronic merit a-IZO thin film. The sputtering power, growth pressure, oxygen partial pressure, and RF/(RF+DC) are varied in a two-level system with a full factorial design, and results are used to deconvolve the complex growth space, identifying significant control growth parameters and their possible interactions. The surface roughness of a-IZO thin film varies over 0.19 nm to 3.97 nm, which is not in line with the general assumption of low surface roughness in a-IZO thin films. The initial regression model and analysis of variance reveal no single optimum growth sub-space to achieve low surface roughness (=0.5 nm), low residual stress (-1 to 0 GPa), and industrially acceptable electrical conductivity (>1000 S/cm) for a-IZO thin films. The extrapolation of growth parameters in light of the current results and previous knowledge leads to a new sub-space, resulting in a low residual stress of -0.52 +/- 0.04 GPa, a low surface roughness of 0.55 +/- 0.03 nm, and moderate electrical conductivity of 1962 +/- 3.84 S/cm in a-IZO thin films. These results demonstrate the utility of the DOE approach to multi-parameter optimization, which provides an important tool for the development of flexible TCOs for the next-generation flexible organic light emitting diodes applications.

  13. 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

    2013-10-07

    alternatives or modifications to those formalisms. These goals are being pursued using data sets obtained from the CIRPAS Twin Otter flown in two...cloud cover ranging from zero to 100%, measure the fluxes at the air- sea interface using the TODWL and CTV instruments flown together near the... Otter . The second step is to compute heat, moisture and momentum fluxes for both the CTV and Twin Otter flux sensors. The computation of fluxes from

  14. 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

  15. 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.

  16. 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.

  17. The stearoyl-coenzyme A desaturase 1 is essential for virulence and membrane stress in Candida parapsilosis through unsaturated fatty acid production.

    PubMed

    Nguyen, Long Nam; Gacser, Attila; Nosanchuk, Joshua D

    2011-01-01

    Unsaturated fatty acids (UFA) are essential components of cells. In Saccharomyces cerevisiae, stearoyl-coenzyme A (CoA) desaturase 1 (OLE1) affects cell viability through the regulation of oleic (18:1) or palmitoleic (16:1) acid production. In this study, we used a targeted gene deletion approach to determine the impact of OLE1 on the emerging human pathogenic fungus Candida parapsilosis. We found that the deletion of OLE1 resulted in an auxotrophic yeast strain (designated OLE1 KO) that required unsaturated fatty acids for growth but not saturated fatty acids. Additionally, the production of UFA by OLE1 KO yeast cells was markedly reduced, suggesting that Ole1 is essential for UFA production. In contrast to wild-type C. parapsilosis, which produced pseudohyphal growth on UFA-supplemented medium agar, pseudohyphal formation in the OLE1 KO cells was severely impaired, suggesting that Ole1 regulates morphology. Furthermore, the OLE1 KO cells were hypersensitive to various stress-inducing factors, such as salts, SDS, and H(2)O(2), especially at the physiological temperature. The results indicate that OLE1 is essential for the stress response, perhaps through the production of UFA for cell membrane biosynthesis. The OLE1 KO cells also were hypersensitive to human and fetal bovine serum, suggesting that targeting Ole1 could suppress the dissemination of yeast cells in the bloodstream. Murine-like macrophage J774.16 more efficiently killed the OLE1 KO yeasts, and significantly larger amounts of nitric oxide were detected in cocultures of macrophages and OLE1 KO cells than with wild-type or heterozygous strains. Moreover, the disruption of OLE1 significantly reduced fungal virulence in systemic murine infection. Taken together, these results demonstrate that Ole1 regulates the pathobiology of C. parapsilosis via UFA and that the OLE1 pathway is a promising antifungal target.

  18. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2010-08-03

    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.

  19. Fluorescent filtered electrophosphorescence

    DOEpatents

    Forrest, Stephen R.; Sun, Yiru; Giebink, Noel; Thompson, Mark E.

    2009-01-06

    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.

  20. Analysis of thermal degradation of organic light-emitting diodes with infrared imaging and impedance spectroscopy.

    PubMed

    Kwak, Kiyeol; Cho, Kyoungah; Kim, Sangsig

    2013-12-02

    We propose a route to examine the thermal degradation of organic light-emitting diodes (OLEDs) with infrared (IR) imaging and impedance spectroscopy. Four different OLEDs with tris (8-hydroxyquinolinato) aluminum are prepared in this study for the analysis of thermal degradation. Our comparison of the thermal and electrical characteristics of these OLEDs reveals that the real-time temperatures of these OLEDs obtained from the IR images clearly correlate with the electrical properties and lifetimes. The OLED with poor electrical properties shows a fairly high temperature during the operation and a considerably short lifetime. Based on the correlation of the real-time temperature and the performance of the OLEDs, the impedance results suggest different thermal degradation mechanisms for each of the OLEDs. The analysis method suggested in this study will be helpful in developing OLEDs with higher efficiency and longer lifetime.

  1. Mechanisms of olive leaf extract-ameliorated rat arthritis caused by kaolin and carrageenan.

    PubMed

    Gong, Dezheng; Geng, Chengyan; Jiang, Liping; Wang, Lihui; Yoshimura, Hiroyuki; Zhong, Laifu

    2012-03-01

    Olive leaf extract (OLE) has antioxidant and antiinflammatory actions. However, the role of OLE in mechanical inflammatory arthritis (osteoarthritis, OA) is unclear. This study investigated the effect of OLE on the development of kaolin and carrageenan-induced arthritis, a murine model of OA. Administration of OLE significantly ameliorated paw swelling, the paw Evans blue content and the histopathological scores. In the human monocyte cell line, THP-1, the OLE reduced the LPS-induced TNF-α production and was dose dependent. Croton oil-induced ear edema in mice also revealed that treatment with OLE suppressed ear edema, myeloperoxidase (MPO) production and was dose dependent. These results indicated that OLE is an effective antiarthritis agent through an antiinflammation mechanism. Also OLE may be beneficial for the treatment of OA in humans.

  2. Fabrication of natural DNA-containing organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Gomez, Eliot F.; Spaeth, Hans D.; Steckl, Andrew J.; Grote, James G.

    2011-09-01

    The process of creating natural DNA-containing bio-organic light emitting diodes is a fascinating journey from salmon fish to the highly-efficient BiOLED. DNA from salmon sperm is used as a high-performance electron blocking layer, to enhance the efficiency of the BiOLED over its conventional OLED counterpart. An overview of the BiOLED fabrication process and its key steps are presented in this paper.

  3. The spectrum of olive pollen allergens.

    PubMed

    Rodríguez, R; Villalba, M; Monsalve, R I; Batanero, E

    2001-07-01

    Olive pollen is one of the most important causes of seasonal respiratory allergy in Mediterranean countries, where this tree is intensely cultivated. Among the high number of protein allergens detected in this pollen, 8 - Ole e 1 to Ole e 8 - have been isolated and characterized. Ole e 1 is the most frequent sensitizing agent, affecting more than 70% of the patients suffering of olive pollinosis, although others, such as Ole e 4 and Ole e 7, have also been shown to be major allergens. In this context, the prevalence of many olive pollen allergens seems to be dependent on the geographical area where the sensitized patients live. Some of the olive allergens have been revealed as members of known protein families: profilin (Ole e 2), Ca(2+)-binding proteins (Ole e 3 and Ole e 8), superoxide dismutase (Ole e 5) and lipid transfer protein (Ole e 7). No biological function has been demonstrated for Ole e 1, whereas Ole e 4 and Ole e 6 are new proteins without homology to known sequences from databases. cDNAs encoding for Ole e 1, Ole e 3 and Ole e 8 have been overproduced in heterologous systems. The recombinant products were correctly folded and exhibited the functional activities of the natural allergens. In addition to the Oleaceae family, other species, such as Gramineae or Betulaceae, contain pollen allergens structurally or immunologically related to those of the olive tree. This fact allows to detect and evaluate antigenic cross-reactivities involving olive allergens. The aim of this research is the development of new diagnostic tools for olive pollinosis and new approaches to improve the classical immunotherapy.

  4. Electroluminescent apparatus having a structured luminescence conversion layer

    DOEpatents

    Krummacher, Benjamin Claus

    2008-09-02

    An apparatus such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer disposed on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains color-changing and non-color-changing regions arranged in a particular pattern.

  5. Oral Administration of Oleuropein and Its Semisynthetic Peracetylated Derivative Prevents Hepatic Steatosis, Hyperinsulinemia, and Weight Gain in Mice Fed with High Fat Cafeteria Diet.

    PubMed

    Lepore, Saverio Massimo; Morittu, Valeria Maria; Celano, Marilena; Trimboli, Francesca; Oliverio, Manuela; Procopio, Antonio; Di Loreto, Carla; Damante, Giuseppe; Britti, Domenico; Bulotta, Stefania; Russo, Diego

    2015-01-01

    The high consumption of olive tree products in the Mediterranean diet has been associated with a lower incidence of metabolic disorders and cardiovascular diseases. In particular, the protective effects of olive oil have been attributed to the presence of polyphenols such as oleuropein (Ole) and its derivatives. We have synthesized a peracetylated derivative of Ole (Ac-Ole) which has shown in vitro antioxidant and growth-inhibitory activity higher than the natural molecule. In this study, male C57BL/6JOlaHsd mice were fed with a standard (std), cafeteria (caf) diet, and caf diet supplemented with Ole (0.037 mmol/kg/day) and Ac-Ole (0.025 mmol/kg/day) for 15 weeks. We observed a significant reduction in the caf diet-induced body weight gain and increase of abdominal adipose tissue. Also, Ole and Ac-Ole prevented the development of hepatic steatosis. Finally, Ole and Ac-Ole determined a lower increase of HDL and LDL-cholesterol levels and corrected caf diet-induced elevation of plasma glucose concentrations by improving insulin sensitivity. The observed beneficial properties of Ole and Ac-Ole make these compounds and in particular Ac-Ole promising candidates for a potential pharmaceutic use in metabolic disorders.

  6. Expected and Actual Student Use of an Online Learning Environment: A Critical Analysis

    ERIC Educational Resources Information Center

    Beasley, Nicola; Smyth, Keith

    2004-01-01

    While Online Learning Environments (OLEs) can potentially support learning that is more autonomous and authentic in nature than traditional instructional environments often allow, students do not always use OLEs in the ways expected or desired by their tutors. This paper examines the findings of a recent evaluation of an OLE designed for…

  7. Oral Administration of Oleuropein and Its Semisynthetic Peracetylated Derivative Prevents Hepatic Steatosis, Hyperinsulinemia, and Weight Gain in Mice Fed with High Fat Cafeteria Diet

    PubMed Central

    Lepore, Saverio Massimo; Morittu, Valeria Maria; Celano, Marilena; Trimboli, Francesca; Oliverio, Manuela; Procopio, Antonio; Di Loreto, Carla; Damante, Giuseppe; Britti, Domenico; Bulotta, Stefania; Russo, Diego

    2015-01-01

    The high consumption of olive tree products in the Mediterranean diet has been associated with a lower incidence of metabolic disorders and cardiovascular diseases. In particular, the protective effects of olive oil have been attributed to the presence of polyphenols such as oleuropein (Ole) and its derivatives. We have synthesized a peracetylated derivative of Ole (Ac-Ole) which has shown in vitro antioxidant and growth-inhibitory activity higher than the natural molecule. In this study, male C57BL/6JOlaHsd mice were fed with a standard (std), cafeteria (caf) diet, and caf diet supplemented with Ole (0.037 mmol/kg/day) and Ac-Ole (0.025 mmol/kg/day) for 15 weeks. We observed a significant reduction in the caf diet-induced body weight gain and increase of abdominal adipose tissue. Also, Ole and Ac-Ole prevented the development of hepatic steatosis. Finally, Ole and Ac-Ole determined a lower increase of HDL and LDL-cholesterol levels and corrected caf diet-induced elevation of plasma glucose concentrations by improving insulin sensitivity. The observed beneficial properties of Ole and Ac-Ole make these compounds and in particular Ac-Ole promising candidates for a potential pharmaceutic use in metabolic disorders. PMID:26798341

  8. Influence des conditions climatiques saisonnières sur quelques paramètres physiologiques dès boucs Créoles alimentés avec de l'ensilage de banane

    NASA Astrophysics Data System (ADS)

    Fauconneau, B.; Xande, A.

    1986-06-01

    Response of three groups of 12 male creole goats (weighing about 10 kg) to environmental variations was tested in Guadeloupe (French West Indies) respectively at three times in the year: end of humid season (October November), dry season (February March) and beginning of humid season (July August). Voluntary free intake of banana silage (silage of mixed green banana, bagassa, wheat bran and urea complemented with molasse) was not significantly affected by climatic variations. Three physiological parameters: rectal temperature, respiratory frequency and cardiac frequency were measured. These parameters were correlated with heat production dependent factors such as metabolic body weight, body weight gain and voluntary free intake. Rectal temperature increased all through the day until sunset and then decreased during the night. Both minimal rectal temperature and daily increase of rectal temperature were correlated with ambient temperature. Cardiac frequency increased during feeding. Generally cardiac frequency seemed to be correlated with activity of animals and so with behavioural response to environmental variations. Respiratory frequency was the most sensitive index of goat response to climate. The daily increase of respiratory frequency was important at the end of the humid season but was not observed in dry season. This increase was dependent on ambient temperature increase but also on air humidity characteristics and air velocity. These points are discussed according to integration of those physiological parameters in thermoregulation.

  9. Genome-Wide Analysis of Oleosin Gene Family in 22 Tree Species: An Accelerator for Metabolic Engineering of BioFuel Crops and Agrigenomics Industrial Applications?

    PubMed Central

    2015-01-01

    Abstract Trees contribute to enormous plant oil reserves because many trees contain 50%–80% of oil (triacylglycerols, TAGs) in the fruits and kernels. TAGs accumulate in subcellular structures called oil bodies/droplets, in which TAGs are covered by low-molecular-mass hydrophobic proteins called oleosins (OLEs). The OLEs/TAGs ratio determines the size and shape of intracellular oil bodies. There is a lack of comprehensive sequence analysis and structural information of OLEs among diverse trees. The objectives of this study were to identify OLEs from 22 tree species (e.g., tung tree, tea-oil tree, castor bean), perform genome-wide analysis of OLEs, classify OLEs, identify conserved sequence motifs and amino acid residues, and predict secondary and three-dimensional structures in tree OLEs and OLE subfamilies. Data mining identified 65 OLEs with perfect conservation of the “proline knot” motif (PX5SPX3P) from 19 trees. These OLEs contained >40% hydrophobic amino acid residues. They displayed similar properties and amino acid composition. Genome-wide phylogenetic analysis and multiple sequence alignment demonstrated that these proteins could be classified into five OLE subfamilies. There were distinct patterns of sequence conservation among the OLE subfamilies and within individual tree species. Computational modeling indicated that OLEs were composed of at least three α-helixes connected with short coils without any β-strand and that they exhibited distinct 3D structures and ligand binding sites. These analyses provide fundamental information in the similarity and specificity of diverse OLE isoforms within the same subfamily and among the different species, which should facilitate studying the structure-function relationship and identify critical amino acid residues in OLEs for metabolic engineering of tree TAGs. PMID:26258573

  10. Genome-Wide Analysis of Oleosin Gene Family in 22 Tree Species: An Accelerator for Metabolic Engineering of BioFuel Crops and Agrigenomics Industrial Applications?

    PubMed

    Cao, Heping

    2015-09-01

    Trees contribute to enormous plant oil reserves because many trees contain 50%-80% of oil (triacylglycerols, TAGs) in the fruits and kernels. TAGs accumulate in subcellular structures called oil bodies/droplets, in which TAGs are covered by low-molecular-mass hydrophobic proteins called oleosins (OLEs). The OLEs/TAGs ratio determines the size and shape of intracellular oil bodies. There is a lack of comprehensive sequence analysis and structural information of OLEs among diverse trees. The objectives of this study were to identify OLEs from 22 tree species (e.g., tung tree, tea-oil tree, castor bean), perform genome-wide analysis of OLEs, classify OLEs, identify conserved sequence motifs and amino acid residues, and predict secondary and three-dimensional structures in tree OLEs and OLE subfamilies. Data mining identified 65 OLEs with perfect conservation of the "proline knot" motif (PX5SPX3P) from 19 trees. These OLEs contained >40% hydrophobic amino acid residues. They displayed similar properties and amino acid composition. Genome-wide phylogenetic analysis and multiple sequence alignment demonstrated that these proteins could be classified into five OLE subfamilies. There were distinct patterns of sequence conservation among the OLE subfamilies and within individual tree species. Computational modeling indicated that OLEs were composed of at least three α-helixes connected with short coils without any β-strand and that they exhibited distinct 3D structures and ligand binding sites. These analyses provide fundamental information in the similarity and specificity of diverse OLE isoforms within the same subfamily and among the different species, which should facilitate studying the structure-function relationship and identify critical amino acid residues in OLEs for metabolic engineering of tree TAGs.

  11. Assessment of the Antimicrobial Activity of Olive Leaf Extract Against Foodborne Bacterial Pathogens

    PubMed Central

    Liu, Yanhong; McKeever, Lindsay C.; Malik, Nasir S. A.

    2017-01-01

    Olive leaf extract (OLE) has been used traditionally as a herbal supplement since it contains polyphenolic compounds with beneficial properties ranging from increasing energy levels, lowering blood pressure, and supporting the cardiovascular and immune systems. In addition to the beneficial effects on human health, OLE also has antimicrobial properties. The aim of this work was to investigate the antimicrobial effect of OLE against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis. Our results demonstrated that at a concentration of 62.5 mg/ml, OLE almost completely inhibited the growth of these three pathogens. In addition, OLE also reduced cell motility in L. monocytogenes, which correlated with the absence of flagella as shown by scanning electron microscopy. Moreover, OLE inhibited biofilm formation in L. monocytogenes and S. Enteritidis. Taken together, OLE, as a natural product, has the potential to be used as an antimicrobial to control foodborne pathogens. PMID:28210244

  12. Plant Phenols as Antibiotic Boosters: In Vitro Interaction of Olive Leaf Phenols with Ampicillin.

    PubMed

    Lim, Anxy; Subhan, Nusrat; Jazayeri, Jalal A; John, George; Vanniasinkam, Thiru; Obied, Hassan K

    2016-03-01

    The antimicrobial properties of olive leaf extract (OLE) have been well recognized in the Mediterranean traditional medicine. Few studies have investigated the antimicrobial properties of OLE. In this preliminary study, commercial OLE and its major phenolic secondary metabolites were evaluated in vitro for their antimicrobial activities against Escherichia coli and Staphylococcus aureus, both individually and in combination with ampicillin. Besides luteolin 7-O-glucoside, OLE and its major phenolic secondary metabolites were effective against both bacteria, with more activity on S. aureus. In combination with ampicillin, OLE, caffeic acid, verbascoside and oleuropein showed additive effects. Synergistic interaction was observed between ampicillin and hydroxytyrosol. The phenolic composition of OLE and the stability of olive phenols in assay medium were also investigated. While OLE and its phenolic secondary metabolites may not be potent enough as stand-alone antimicrobials, their abilities to boost the activity of co-administered antibiotics constitute an imperative future research area.

  13. [Development of electroencephalography for the localization of invasive lesions].

    PubMed

    Sitzer, G

    1983-03-24

    Hjorth described a special multielectrode derived from a theory of Laplace. This type of derivation will accentuate the contribution of the potential field under the active electrode relative to the surrounding electrical activity and is therefore called "source derivation". Preliminary clinical studies seem to confirm the supposition that source derivations tend to focus activity from individual electrodes in a better way than standard derivations do. Technical changes in a 16-channel EEG are the reason for simultaneously EEG-recording to test the method of the standard derivation (uni- and bipolar) against the source derivation. Total of 4280 EEGs have been recorded concerning the generalisation of activity, focal activity by epilepsia, cerebro-vascular disease and tumors of the brain. In most of the recordings focal activity was more sharply pronounced in source than in conventional derivations with problematical reference points.

  14. Broadening the scope of glycosyltransferase-catalyzed sugar nucleotide synthesis.

    PubMed

    Gantt, Richard W; Peltier-Pain, Pauline; Singh, Shanteri; Zhou, Maoquan; Thorson, Jon S

    2013-05-07

    We described the integration of the general reversibility of glycosyltransferase-catalyzed reactions, artificial glycosyl donors, and a high throughput colorimetric screen to enable the engineering of glycosyltransferases for combinatorial sugar nucleotide synthesis. The best engineered catalyst from this study, the OleD Loki variant, contained the mutations P67T/I112P/T113M/S132F/A242I compared with the OleD wild-type sequence. Evaluated against the parental sequence OleD TDP16 variant used for screening, the OleD Loki variant displayed maximum improvements in k(cat)/K(m) of >400-fold and >15-fold for formation of NDP-glucoses and UDP-sugars, respectively. This OleD Loki variant also demonstrated efficient turnover with five variant NDP acceptors and six variant 2-chloro-4-nitrophenyl glycoside donors to produce 30 distinct NDP-sugars. This study highlights a convenient strategy to rapidly optimize glycosyltransferase catalysts for the synthesis of complex sugar nucleotides and the practical synthesis of a unique set of sugar nucleotides.

  15. Olive leaf extract facilitates healing of experimental cartilaginous injuries in rabbits.

    PubMed

    Gong, Dezheng; Geng, Chengyan; Jiang, Liping; Wang, Lihui; Yoshimuram, Hiroyuki; Zhong, Laifu

    2011-03-01

    We investigated the restorative effect of orally administered olive leaf extract (OLE) on experimentally produced cartilaginous injuries in rabbits. In total, three holes in the left stifle joint, including one in the medial trochlear ridge and two in the trochlear sulcus (proximal and distal) of articular cartilage, were prepared surgically using a drill. For the control group only tap water alone was administered daily, and for the OLE group a water-based solution of OLE (500 mg/kg/day) was administered daily. The injured areas were observed macroscopically and histologically at 3 weeks after the operation. The results indicate that OLE facilitated healing of the three holes and increased the weight of the biceps femoris muscle. Histological examination revealed that in the OLE group, matured cartilage tissues and connective tissues were mixed with regenerated or maturing cartilage tissues with massive proliferation in the injured parts, around which the proliferation of undifferentiated blast cells and the tissue with cartilage substrates were observed. The histological score of the OLE group was significantly lower than that of the control group. The percentage of proliferating cell nuclear antigen-positive cartilage cells in the OLE group was higher than in the control group. Mean density of the restored area observed with Safranin O staining was higher in the OLE group than in the control group. Therefore, OLE is effective for enhancing the healing of cartilaginous injuries. OLE may also have a beneficial effect of slowing and reducing the pathogenesis of degenerative joint diseases in humans.

  16. Flexible microstructured organic light sources for automotive applications

    NASA Astrophysics Data System (ADS)

    Melpignano, Patrizia; Sinesi, Sabino; Toaldo, A. Baron; Biondo, Viviana; Muccini, Michele; Zamboni, Roberto; Gale, Michael T.; Westenhofer, Susanne

    2004-09-01

    Organic light-emitting diodes (OLED) are rapidly reaching large-scale marketing figures, driven by attractive features like low cost and fast response, being also suitable for application on flexible substrates. All these aspects enable a wide range of applications such as displays, innovative devices in optoelectronics and novel light sources. Furthermore, the benefits expected from OLEDs based devices, if compared to "classical semiconductors" based devices consist of low production costs, lightweight and geometrical flexibility. Novel OLEDs based light sources fulfilling the above-mentioned requirements, call for a considerable effort both in the production processes and in product innovation. Among the variety of possible applicative OLED applications, we focused our research effort on the Automotive sector. Our envisioned approach enabling control of light distribution from an OLED light source include modeling and patterning of the light source, design and fabrication of suitable micro-optics coupled to the flexible transparent Organic Light Emitting Diode (OLED) substrate.

  17. Light emitting device having peripheral emissive region

    DOEpatents

    Forrest, Stephen R

    2013-05-28

    Light emitting devices are provided that include one or more OLEDs disposed only on a peripheral region of the substrate. An OLED may be disposed only on a peripheral region of a substantially transparent substrate and configured to emit light into the substrate. Another surface of the substrate may be roughened or include other features to outcouple light from the substrate. The edges of the substrate may be beveled and/or reflective. The area of the OLED(s) may be relatively small compared to the substrate surface area through which light is emitted from the device. One or more OLEDs also or alternatively may be disposed on an edge of the substrate about perpendicular to the surface of the substrate through which light is emitted, such that they emit light into the substrate. A mode expanding region may be included between each such OLED and the substrate.

  18. Study on constant-step stress accelerated life tests in white organic light-emitting diodes.

    PubMed

    Zhang, J P; Liu, C; Chen, X; Cheng, G L; Zhou, A X

    2014-11-01

    In order to obtain reliability information for a white organic light-emitting diode (OLED), two constant and one step stress tests were conducted with its working current increased. The Weibull function was applied to describe the OLED life distribution, and the maximum likelihood estimation (MLE) and its iterative flow chart were used to calculate shape and scale parameters. Furthermore, the accelerated life equation was determined using the least squares method, a Kolmogorov-Smirnov test was performed to assess if the white OLED life follows a Weibull distribution, and self-developed software was used to predict the average and the median lifetimes of the OLED. The numerical results indicate that white OLED life conforms to a Weibull distribution, and that the accelerated life equation completely satisfies the inverse power law. The estimated life of a white OLED may provide significant guidelines for its manufacturers and customers.

  19. Application of nano-encapsulated olive leaf extract in controlling the oxidative stability of soybean oil.

    PubMed

    Mohammadi, Adeleh; Jafari, Seid Mahdi; Esfanjani, Afshin Faridi; Akhavan, Sahar

    2016-01-01

    Our objective was to evaluate the antioxidant activity of olive leave extract (OLE) encapsulated by nano-emulsions in soybean oil. The average droplet size one day after production was 6.16 nm for primary W/O nano-emulsion and, 675 nm and 1443 nm for multiple emulsions stabilized by WPC alone and complex of WPC-pectin, respectively. The antioxidant activity of these emulsions containing three concentrations of 100, 200 and 300 mg OLE during storage was evaluated in soybean oil by peroxide value, TBA value and rancimat thermal stability test and was compared with blank (non-encapsulated) OLE and synthetic TBHQ antioxidant. Nano-encapsulated OLE was capable of controlling peroxide value better than unencapsulated OLE. But because of blocking phenolic compounds within dispersed emulsions droplets, thermal stability of encapsulated OLE was lower. To summarize, with increased solubility and controlled release of olive leaf phenolic compounds through their nano-encapsulation, a higher antioxidant activity was achieved.

  20. Structured luminescence conversion layer

    DOEpatents

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  1. Organic light-emitting device with a phosphor-sensitized fluorescent emission layer

    DOEpatents

    Forrest, Stephen; Kanno, Hiroshi

    2009-08-25

    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. The emissive region of the devices of the present invention comprise at least one phosphor-sensitized layer which has a combined emission from a phosphorescent emitter and a fluorescent emitter. In preferred embodiments, the invention relates to white-emitting OLEDS (WOLEDs).

  2. Recent advances in stacked inverted top-emitting organic electrophosphorescent diodes (presentation video)

    NASA Astrophysics Data System (ADS)

    Kippelen, Bernard; Knauer, Keith A.; Najafabadi, Ehsan M.; Zhou, Yinhua; Fuentes-Hernandez, Canek

    2014-10-01

    In this talk, we will discuss recent advances in green and white electrophosphorescent stacked organic light-emitting diodes (OLEDs) with inverted top-emitting structures. These devices combine the advantages of having inverted electrode positions, a top-emissive design, and a stacked architecture. We will also demonstrate OLEDs that are fabricated on cellulose nanocrystal substrates and discuss how the use of such naturally-derived materials can reduce the environmental footprint of organic electronic devices such as OLEDs.

  3. Parallel pathways for oxidation of 14-membered polyketide macrolactones in Saccharopolyspora erythraea.

    PubMed

    Gaisser, Sabine; Lill, Rachel; Staunton, James; Méndez, Carmen; Salas, José; Leadlay, Peter F

    2002-05-01

    The glycosyltransferases OleG1 and OleG2 and the cytochrome P450 oxidase OleP from the oleandomycin biosynthetic gene cluster of Streptomyces antibioticus have been expressed, either separately or from artificial gene cassettes, in strains of Saccharopolyspora erythraea blocked in erythromycin biosynthesis, to investigate their potential for the production of diverse novel macrolides from erythronolide precursors. OleP was found to oxidize 6-deoxyerythronolide B, but not erythronolide B. However, OleP did oxidize derivatives of erythronolide B in which a neutral sugar is attached at C-3. The oxidized products 3-O-mycarosyl-8a-hydroxyerythronolide B, 3-O-mycarosyl-8,8a-epoxyerythronolide B, 6-deoxy-8-hydroxyerythronolide B and the olefin 6-deoxy-8,8a-dehydroerythronolide B were all isolated and their structures determined. When oleP and the mycarosyltransferase eryBV were co-expressed in a gene cassette, 3-O-mycarosyl-6-deoxy-8,8a-dihydroxyerythronolide B was directly obtained. When oleG2 was co-expressed in a gene cassette together with oleP, 6-deoxyerythronolide B was converted into a mixture of 3-O-rhamnosyl-6-deoxy-8,8a-dehydroerythronolide B and 3-O-rhamnosyl-6-deoxy-8,8a-dihydroxyerythronolide B, confirming previous reports that OleG2 can transfer rhamnose, and confirming that oxidation by OleP and attachment of the neutral sugar to the aglycone can occur in either order. Similarly, four different 3-O-mycarosylerythronolides were found to be substrates for the desosaminyltransferase OleG1. These results provide additional insight into the nature of the intermediates in OleP-mediated oxidation, and suggest that oleandomycin biosynthesis might follow parallel pathways in which epoxidation either precedes or follows attachment of the neutral sugar.

  4. High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour

    NASA Astrophysics Data System (ADS)

    Morton, Andrew; Murawski, Caroline; Pulver, Stefan R.; Gather, Malte C.

    2016-08-01

    Organic light emitting diodes (OLEDs) are in widespread use in today’s mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm‑2) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments.

  5. High-brightness organic light-emitting diodes for optogenetic control of Drosophila locomotor behaviour

    PubMed Central

    Morton, Andrew; Murawski, Caroline; Pulver, Stefan R.; Gather, Malte C.

    2016-01-01

    Organic light emitting diodes (OLEDs) are in widespread use in today’s mobile phones and are likely to drive the next generation of large area displays and solid-state lighting. Here we show steps towards their utility as a platform technology for biophotonics, by demonstrating devices capable of optically controlling behaviour in live animals. Using devices with a pin OLED architecture, sufficient illumination intensity (0.3 mW.mm−2) to activate channelrhodopsins (ChRs) in vivo was reliably achieved at low operating voltages (5 V). In Drosophila melanogaster third instar larvae expressing ChR2(H134R) in motor neurons, we found that pulsed illumination from blue and green OLEDs triggered robust and reversible contractions in animals. This response was temporally coupled to the timing of OLED illumination. With blue OLED illumination, the initial rate and overall size of the behavioural response was strongest. Green OLEDs achieved roughly 70% of the response observed with blue OLEDs. Orange OLEDs did not produce contractions in larvae, in agreement with the spectral response of ChR2(H134R). The device configuration presented here could be modified to accommodate other small model organisms, cell cultures or tissue slices and the ability of OLEDs to provide patterned illumination and spectral tuning can further broaden their utility in optogenetics experiments. PMID:27484401

  6. Degradation in organic light emitting devices

    NASA Astrophysics Data System (ADS)

    Dinh, Vincent Vinh

    This thesis is about the fundamental causes of degradation in tris(8-Hydroxyquinoline) Aluminum (Alq3)-based organic light emitting diodes (OLEDs). Degradation typically occurs when a current is forced through an insulating material. Since the insulator does not support conduction waves (in its ground state), chemical restructuring must occur to accommodate the current. OLEDs have many technical advantages over the well known semiconductor-based light emitting diodes (LEDs). OLEDs have quantum efficiencies ˜1% (˜10 times higher than the LEDs), and operational power thresholds ˜.05mW (˜100 lower than the LEDs). OLEDs are preferred in power limited and portable devices; devices such as laptops and displays consume ˜1/4 of the supplied power---any power saving is significant. Other advantages, like better compliance to curved surfaces and ease of fabrication, give the OLEDs an even greater edge over the LEDs. OLEDs must have at least comparable or better lifetimes to remain attractive. Typical OLEDs last several 100hrs compared to the several 1000hrs for the LEDs. For reliable OLED application, it is necessary to understand the above breakdown mechanism. In this thesis, we attempt to understand the breakdown by looking at how OLEDs are made, how they work, and when they don't. In the opening sections, we give an overview of OLEDs and LEDs, especially how sustained luminescence is achieved through current circulation. Then in Chapter 2, we look at the basic components in the OLEDs. In Chapter 3 we look at how a hole material (like poly-vinyl carbazole or PVK) establishes an excitonic environment for the sustained luminescence in Alq3. We then approximate how potential is distributed when a simple luminescence system is in operation. In Chapter 4, we look at ways of measuring this distribution via the OLED impedance. Finally in Chapter 5, we look at the OLED stability under light emission conditions via PVK and Alq3 photoemission and photoabsorption spectra

  7. Oleuropein attenuates cognitive dysfunction and oxidative stress induced by some anesthetic drugs in the hippocampal area of rats.

    PubMed

    Alirezaei, Masoud; Rezaei, Maryam; Hajighahramani, Shahin; Sookhtehzari, Ali; Kiani, Katayoun

    2017-01-01

    The present study was designed to evaluate the antioxidant effects of oleuropein against oxidative stress in the hippocampal area of rats. We used seven experimental groups as follows: Control, Propofol, Propofol-Ketamine (Pro.-Ket.), Xylazine-Ketamine (Xyl.-Ket.), and three oleuropein-pretreated groups (Ole.-Pro., Ole.-Pro.-Ket. and Ole.-Xyl.-Ket.). The oleuropein-pretreated groups received oleuropein (15 mg/kg body weight as orally) for 10 consecutive days. Propofol 100 mg/kg, xylazine 3 mg/kg, and ketamine 75 mg/kg once as ip was used on the 11th day of treatment. Spatial memory impairment and antioxidant status of hippocampus were measured via Morris water maze, lipid peroxidation marker, and antioxidant enzyme activities. Spatial memory impairment and lipid peroxidation significantly increased in Xyl.-Ket.-treated rats in comparison to the control, propofol, Ole.-Pro. and Ole.-Pro.-Ket. groups. Oleuropein pretreatment significantly reversed spatial memory impairment and lipid peroxidation in the Ole.-Xyl.-Ket. group as compared to the Xyl.-Ket.-treated rats. There was no significant difference between the control and the propofol group in lipid peroxidation and spatial memory status. Superoxide dismutase and catalase activities both significantly decreased in Xyl.-Ket.-treated rats when compared to the control, propofol, Ole.-Pro., Ole.-Pro.-Ket., and Ole.-Xyl.-Ket. groups. In contrast, glutathione peroxidase activity in Xyl.-Ket.-treated rats significantly increased as compared to the control, propofol, Pro.-Ket., Ole.-Pro., and Ole.-Pro.-Ket. groups. We concluded that xylazine in combination with ketamine is an oxidative anesthetic drug and oleuropein pretreatment attenuates cognitive dysfunction and oxidative stress induced by anesthesia in the hippocampal area of rats. We also confirmed the antioxidant properties of propofol as a promising antioxidant anesthetic agent.

  8. Variations in Interactive Writing Instruction: A Study in Four Bilingual Special Education Settings.

    ERIC Educational Resources Information Center

    Graves, Anne W.; Valles, Eugene C.; Rueda, Robert

    2000-01-01

    A study of four bilingual special education settings found teachers chose different approaches for teaching writing: interactive journals, Optimal Learning Environment (OLE), Writer's Workshop, and a combination of journal writing, brainstorming-planning, and spelling practice. One year later, only participants in OLE demonstrated significant…

  9. Flexible Organic Tribotronic Transistor Memory for a Visible and Wearable Touch Monitoring System.

    PubMed

    Li, Jing; Zhang, Chi; Duan, Lian; Zhang, Li Min; Wang, Li Duo; Dong, Gui Fang; Wang, Zhong Lin

    2016-01-06

    A new type of flexible organic tribotronic transistor memory is proposed, which can be written and erased by externally applied touch actions as an active memory. By further coupling with an organic light-emitting diode (OLED), a visible and wearable touch monitoring system is achieved, in which touch triggering can be memorized and shown as the emission from the OLED.

  10. 50 CFR 660.312 - Vessel Monitoring System (VMS) requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., WA 98115-6349, phone: (206) 526-6133. (2) Activate the mobile transceiver unit, submit an activation... VMS? A VMS consists of a NMFS OLE type-approved mobile transceiver unit that automatically determines... required to have VMS? The following vessels are required to install a NMFS OLE type-approved...

  11. 50 CFR 660.14 - Vessel Monitoring System (VMS) requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 98115-6349, phone: (206) 526-6133. (2) Activate the mobile transceiver unit, submit an activation report...? A VMS consists of a NMFS OLE type-approved mobile transceiver unit that automatically determines the... a VMS? The following vessels are required to install a NMFS OLE type-approved mobile...

  12. Framing and Enhancing Distributed Leadership in the Quality Management of Online Learning Environments in Higher Education

    ERIC Educational Resources Information Center

    Holt, Dale; Palmer, Stuart; Gosper, Maree; Sankey, Michael; Allan, Garry

    2014-01-01

    This article reports on the findings of senior leadership interviews in a nationally funded project on distributed leadership in the quality management of online learning environments (OLEs) in higher education. Questions were framed around the development of an OLE quality management framework and the situation of the characteristics of…

  13. Exploring Distributed Leadership for the Quality Management of Online Learning Environments

    ERIC Educational Resources Information Center

    Palmer, Stuart; Holt, Dale; Gosper, Maree; Sankey, Michael; Allan, Garry

    2013-01-01

    Online learning environments (OLEs) are complex information technology (IT) systems that intersect with many areas of university organisation. Distributed models of leadership have been proposed as appropriate for the good governance of OLEs. Based on theoretical and empirical research, a group of Australian universities proposed a framework for…

  14. Aerosol Single-Scattering Albedo and Asymmetry Parameter from MFRSR Observations during the ARM Aerosol IOP 2003

    SciTech Connect

    Kassianov, Evgueni I.; Flynn, Connor J.; Ackerman, Thomas P.; Barnard, James C.

    2007-06-15

    Multi-filter Rotating Shadowband Radiometers (MFRSRs) provide routine measurements of the aerosol optical depth ( << OLE Object: Microsoft Equation 3.0 >> ) at six wavelengths (0.415, 0.5, 0.615, 0.673, 0.870 and 0.94  << OLE Object: Picture (Metafile) >> ). The single-scattering albedo ( << OLE Object: Microsoft Equation 3.0 >> ) is typically estimated from the MFRSR measurements by assuming the asymmetry parameter ( << OLE Object: Microsoft Equation 3.0 >> ). In most instances, however, it is not easy to set an appropriate value of << OLE Object: Microsoft Equation 3.0 >> due to its strong temporal and spatial variability. Here, we introduce and validate an updated version of our retrieval technique that allows one to estimate simultaneously << OLE Object: Microsoft Equation 3.0 >> and << OLE Object: Microsoft Equation 3.0 >> for different types of aerosol. We use the aerosol and radiative properties obtained during the Atmospheric Science Program (ARM) Aerosol Intensive Operational Period (IOP) to validate our retrieval in two ways. First, the MFRSR-retrieved optical properties are compared with those obtained from independent surface, Aerosol Robotic Network (AERONET) and aircraft measurements. The MFRSR-retrieved optical properties are in reasonable agreement with these independent measurements. Second, we perform radiative closure experiments using the MFRSR-retrieved optical properties. The calculated broadband values of the direct and diffuse fluxes are comparable (~ 5 << OLE Object: Microsoft Equation 3.0 >> ) to those obtained from measurements.

  15. On the Job Training in Line Heating in Astilleros Espanoles Shipyards, A Profitable Experience

    DTIC Science & Technology

    1993-11-01

    FITNESS FOR PURPOSE ARE SPECIFICALLY DISCLAIMED. ABSTRACT This paper describes the experience in teaching Astilleros Españoles (AESA)’ steel...Global Plan for Technological Improvement) Astilleros Españoles , Madrid 1990 (In Spanish). R. Gutiérrez and A. Sarabia, “A Return to Merchant Ship

  16. The Sino-Vietnamese Crisis, 1975-1979: An Historical Case Study.

    DTIC Science & Technology

    1985-05-01

    central qutesti-n. J international crisis management case studies done by Allen Whiting, Ole HlA i, Alexander George, and Richard Smoke form a base for...an historical case study that addresses these central’questions. International crisis management case studies done by Allen Whiting, Ole Holsti

  17. Olive leaf extract concentrated in hydroxytyrosol attenuates protein carbonylation and the formation of advanced glycation end products in a hepatic cell line (HepG2).

    PubMed

    Navarro, Marta; Morales, Francisco J; Ramos, Sonia

    2017-03-22

    Glycation takes place both at the cellular level and at the extracellular matrix level and generates, consequently, advanced glycation end-products (AGEs) associated with chronic diseases and the aging process. Two olive leaf extracts concentrated in (i) oleuropein (OLE-A; 93.9 mg oleuropein g(-1)) and (ii) hydroxytyrosol (OLE-B; 54.5 mg hydroxytyrosol g(-1)) were evaluated according to their antiglycative and antioxidant capacity in vitro. OLE-B exerted the highest anti-AGE effect in different glycation models (IC50: 0.25-0.29 mg mL(-1)). OLE-B showed the highest antioxidant capacity and methylglyoxal-trapping capacity (IC50 0.16 mg mL(-1)). OLE-B showed a significant inhibitory effect against protein carbonylation (21%) and generation of argpyrimidine (26%) in a hepatocyte cellular carbonyl stress model evoked by methylglyoxal (MGO). OLE-B was further fractionated by solid phase-extraction, and the protective effect against protein carbonylation was only exerted by the fraction containing hydroxytyrosol. However, hydroxytyrosol standard, at the same concentration in the extract, inhibited the protein carbonylation below 10% but not significantly. The results indicate that the antiglycative activity of OLE in cells could be due to a synergic effect of hydroxytyrosol and other minor compounds with similar polarity. The research of the antiglycative activity in vivo could confirm these promising results and to propose OLE as a natural anti-AGE agent.

  18. Trajectories of Engagement: A Repeated Cross-Sectional Investigation of Student Perceptions of an Online Learning Environment

    ERIC Educational Resources Information Center

    Palmer, Stuart; Holt, Dale

    2012-01-01

    Evaluations of online learning environments (OLEs) often present a snapshot of system use. It has been identified in the literature that extended evaluation is required to reveal statistically significant developments in the evolution of system use over time. The research presented here draws on student OLE evaluations surveys run over the period…

  19. 50 CFR 660.14 - Vessel Monitoring System (VMS) requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Sand Point Way NE., Seattle, WA 98115-6349, phone: (206) 526-6133. (2) Activate the mobile transceiver...? A VMS consists of a NMFS OLE type-approved mobile transceiver unit that automatically determines the... a VMS? The following vessels are required to install a NMFS OLE type-approved mobile...

  20. 50 CFR 660.14 - Vessel Monitoring System (VMS) requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Sand Point Way NE., Seattle, WA 98115-6349, phone: (206) 526-6133. (2) Activate the mobile transceiver...? A VMS consists of a NMFS OLE type-approved mobile transceiver unit that automatically determines the... a VMS? The following vessels are required to install a NMFS OLE type-approved mobile...

  1. 50 CFR 660.14 - Vessel Monitoring System (VMS) requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Sand Point Way NE., Seattle, WA 98115-6349, phone: (206) 526-6133. (2) Activate the mobile transceiver...? A VMS consists of a NMFS OLE type-approved mobile transceiver unit that automatically determines the... a VMS? The following vessels are required to install a NMFS OLE type-approved mobile...

  2. Antihypertensive effects of oleuropein-enriched olive leaf extract in spontaneously hypertensive rats.

    PubMed

    Romero, M; Toral, M; Gómez-Guzmán, M; Jiménez, R; Galindo, P; Sánchez, M; Olivares, M; Gálvez, J; Duarte, J

    2016-01-01

    The effects of chronic consumption of oleuropein-enriched (15% w/w) olive leaf extract (OLE) on blood pressure, endothelial function, and vascular oxidative and inflammatory status in spontaneously hypertensive rats (SHR) were evaluated. Ten Wistar Kyoto rats (WKY) and twenty SHR were randomly assigned to three groups: a control WKY group, a control SHR group and a SHR group treated with OLE (30 mg kg(-1)) for 5 weeks. Long-term administration of OLE reduced systolic blood pressure, heart rate, and cardiac and renal hypertrophy. OLE treatment reversed the impaired aortic endothelium-dependent relaxation to acetylcholine observed in SHR. OLE restored aortic eNOS phosphorylation at Ser-1177 and Thr-495 and increased eNOS activity. OLE eliminated the increased aortic superoxide levels, and reduced the elevated NADPH oxidase activity, as a result of reduced NOX-1 and NOX-2 mRNA levels in SHR. OLE reduced the enhanced vascular TLR4 expression by inhibition of mitogen-activated protein kinase (MAPK) signaling with the subsequent reduction of proinflammatory cytokines. In conclusion, OLE exerts antihypertensive effects on genetic hypertension related to the improvement of vascular function as a result of reduced pro-oxidative and pro-inflammatory status.

  3. Sensory quality of functional beverages: bitterness perception and bitter masking of olive leaf extract fortified fruit smoothies.

    PubMed

    Kranz, Peter; Braun, Nina; Schulze, Nadine; Kunz, Benno

    2010-08-01

    Olive leaf extract (OLE) contains high amounts of oleuropein and hydroxytyrosol. The antioxidant capacity of these polyphenols makes OLE a promising ingredient for functional food. OLE causes very strong bitterness perception and can therefore only be formulated in low concentrations. In this research, bitter detection and recognition thresholds of OLE-fortified fruit smoothies were determined by a trained sensory panel (n = 11). Masking of the OLE's bitter taste was investigated with addition of sodium cyclamate, sodium chloride, and sucrose by means of a standardized ranking method and a scale test. Detection (5.78 mg/100 g) and recognition thresholds (8.05 mg/100 g) of OLE polyphenols confirmed the low formulation limits when bitterness was not masked by other substances. At higher polyphenol levels of 20 mg/100 g, sodium cyclamate and sucrose were able to reduce bitter taste perception by 39.9% and 24.9%, respectively, whereas sodium chloride could not effectively mask bitterness. Practical Application: Development of functional food poses new challenges for the food industry. A major problem in this field is the high bitterness of natural polyphenol-containing extracts with potential health benefits. This research was conducted to understand the sensory impact of olive leaf extract (OLE), a novel food ingredient with very bitter taste. In product development, the data of this research can be considered for formulation limits and the general sensory quality of OLE-fortified food and beverages.

  4. Identification, classification and differential expression of oleosin genes in tung tree (Vernicia fordii)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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),...

  5. Very high efficiency phosphorescent organic light-emitting devices by using rough indium tin oxide

    SciTech Connect

    Zhang, Yingjie; Aziz, Hany

    2014-07-07

    The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on the roughness of the indium tin oxide (ITO) anode. By using rougher ITO, light trapped in the ITO/organic wave-guided mode can be efficiently extracted, and a light outcoupling enhancement as high as 40% is achieved. Moreover, contrary to expectations, the lifetime of OLEDs is not affected by ITO roughness. Finally, an OLED employing rough ITO anode that exhibits a current efficiency of 56 cd/A at the remarkably high brightness of 10{sup 5} cd/m{sup 2} is obtained. This represents the highest current efficiency at such high brightness to date for an OLED utilizing an ITO anode, without any external light outcoupling techniques. The results demonstrate the significant efficiency benefits of using ITO with higher roughness in OLEDs.

  6. Lifetime of organic light emitting diodes on polymer anodes

    NASA Astrophysics Data System (ADS)

    Fehse, Karsten; Meerheim, Rico; Walzer, Karsten; Leo, Karl; Lövenich, Wilfried; Elschner, Andreas

    2008-08-01

    We report on the use of a thin layer of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) as anode for bottom emission organic light emitting diodes (OLEDs). The combination of polymer anodes with OLEDs having either electrically doped or undoped hole transport layers in direct contact with the polymer is shown. We discuss the impact of the annealing conditions of the polymer on the OLED lifetime in comparison to indium tin oxide anodes. Supported by a differential thermal analysis of PEDOT:PSS, a strong influence of residual water in the polymer on the device lifetime is found. Additional heating of the polymer anode in a dry ambient prior to OLED deposition is necessary to achieve high device lifetimes. At a luminance of 260 cd/m2, pin-OLEDs on a PEDOT:PSS anode show no measurable device degradation during 5200 h of operation.

  7. Color stabilization in white organic light emitting devices utilizing trapping layers inserted in both an electron transport layer and an emitting layer.

    PubMed

    Kwack, Byoung Chan; Lee, Kwang Seop; Choo, Dong Chul; Kim, Tae Whan; Seo, Ji Hyun; Kim, Young Kwan

    2008-10-01

    The electrical and the optical properties of white organic light emitting devices (OLEDs) utilizing trapping layers inserted into both an electron transport layer (ETL) and an emitting layer (EML) were investigated. The current density of OLEDs with an ETL containing a 5,6,11,12-tetraphenylnaphthacene (rubrene) layer was slightly smaller than those of other devices. The luminance-current density and luminance efficiency-current density of the OLEDs with rubrene layers embedded in only an ETL or an EML were similar to the blue reference device. While the electroluminescence (EL) spectrum for the OLEDs with a rubrene layer in the ETL in the low voltage range showed the white color, that with rubrene layers in both the EML and the ETL exhibited white color, regardless of the applied voltage. The Commission International de l'Eclairage coordinates of the white OLEDs became stabilized by inserting rubrene layers into both the EML and the ETL.

  8. Principles of phosphorescent organic light emitting devices.

    PubMed

    Minaev, Boris; Baryshnikov, Gleb; Agren, Hans

    2014-02-07

    Organic light-emitting device (OLED) technology has found numerous applications in the development of solid state lighting, flat panel displays and flexible screens. These applications are already commercialized in mobile phones and TV sets. White OLEDs are of especial importance for lighting; they now use multilayer combinations of organic and elementoorganic dyes which emit various colors in the red, green and blue parts of the visible spectrum. At the same time the stability of phosphorescent blue emitters is still a major challenge for OLED applications. In this review we highlight the basic principles and the main mechanisms behind phosphorescent light emission of various classes of photofunctional OLED materials, like organic polymers and oligomers, electron and hole transport molecules, elementoorganic complexes with heavy metal central ions, and clarify connections between the main features of electronic structure and the photo-physical properties of the phosphorescent OLED materials.

  9. Neuropsychological profile of adult patients with nonsymptomatic occipital lobe epilepsies.

    PubMed

    Bilo, Leonilda; Santangelo, Gabriella; Improta, Ilaria; Vitale, Carmine; Meo, Roberta; Trojano, Luigi

    2013-02-01

    To explore the neuropsychological and neurobehavioral profile in adult patients affected by nonsymptomatic (cryptogenic and idiopathic) occipital lobe epilepsy (OLE), with normal intelligence, we enrolled 20 adult patients with nonsymptomatic OLE and 20 age-, sex-, and education-matched healthy subjects. All participants underwent neuropsychiatric assessment scales, and standardized neuropsychological tests tapping memory, executive functions, constructional, visuospatial and visuoperceptual skills. After Bonferroni correction for multiple comparisons, patients performed significantly worse than controls on several tests tapping complex visuospatial skills and frontal lobe functions. The analysis of single patients' performance revealed that a significantly higher number of OLE patients achieved age- and education-adjusted pathological scores on three tests (Benton Judgment of Line Orientation Test, Freehand Copying of Drawings Test, color-word interference task of Stroop test) with respect to controls. Patients did not differ from control subjects on neuropsychiatric aspects. The direct comparison between OLE subtypes showed that cryptogenetic OLE patients tended to achieve lower scores than idiopathic OLE patients on most tests, but no difference between the two groups was fully significant. In summary, patients with nonsymptomatic OLE can be affected by clinically relevant impairments in selected neuropsychological domains: complex visuospatial skills and executive functions. It could be speculated that frontal and visuospatial cognitive deficits might be the result of epileptic activity spreading within a neural network that includes structures far beyond the occipital lobe.

  10. Oleuropein aglycone induces autophagy via the AMPK/mTOR signalling pathway: a mechanistic insight

    PubMed Central

    Nediani, Chiara; Berti, Andrea; Cascella, Roberta; Pantano, Daniela; Nardiello, Pamela; Luccarini, Ilaria; Casamenti, Fiorella; Stefani, Massimo

    2015-01-01

    The healthy effects of plant polyphenols, some of which characterize the so-called Mediterranean diet, have been shown to arise from epigenetic and biological modifications resulting, among others, in autophagy stimulation. Our previous work highlighted the beneficial effects of oleuropein aglycone (OLE), the main polyphenol found in the extra virgin olive oil, against neurodegeneration both in cultured cells and in model organisms, focusing, in particular, autophagy activation. In this study we investigated more in depth the molecular and cellular mechanisms of autophagy induction by OLE using cultured neuroblastoma cells and an OLE-fed mouse model of amylod beta (Aβ) deposition. We found that OLE triggers autophagy in cultured cells through the Ca2+-CAMKKβ–AMPK axis. In particular, in these cells OLE induces a rapid release of Ca2+ from the SR stores which, in turn, activates CAMKKβ, with subsequent phosphorylation and activation of AMPK. The link between AMPK activation and mTOR inhibition was shown in the OLE-fed animal model in which we found that decreased phospho-mTOR immunoreactivity and phosphorylated mTOR substrate p70 S6K levels match enhanced phospho-AMPK levels, supporting the idea that autophagy activation by OLE proceeds through mTOR inhibition. Our results agree with those reported for other plant polyphenols, suggesting a shared molecular mechanism underlying the healthy effects of these substances against ageing, neurodegeneration, cancer, diabetes and other diseases implying autophagy dysfunction. PMID:26474288

  11. Yellow/orange emissive heavy-metal complexes as phosphors in monochromatic and white organic light-emitting devices.

    PubMed

    Fan, Cong; Yang, Chuluo

    2014-09-07

    Owing to the electron spin-orbit coupling (SOC) and fast intersystem crossing (ISC), heavy-metal complexes (such as iridium(III), platinum(II) and osmium(II) complexes, etc.) are phosphorescent emitters at room temperature. Since 1998, heavy-metal complexes as phosphors have received considerable academic and industrial attention in the field of organic light-emitting diodes (OLEDs), because they can harvest both the singlet (25%) and triplet (75%) excitons for emission during the electro-generated processes. Among all the visible colors (blue, green, yellow, orange and red), the yellow/orange heavy-metal complexes play an important role for realizing full-color OLEDs as well as high-efficiency white OLEDs, and thus the development of highly efficient yellow/orange heavy-metal complexes is a pressing concern. In this article, we will review the progress on yellow/orange heavy-metal complexes as phosphors in OLEDs. The general principles and useful tactics for designing the yellow/orange heavy-metal complexes will be systematically summarized. The structure-property relationship and electrophosphorescence performance of the yellow/orange heavy-metal complexes in monochromatic phosphorescent OLEDs (PhOLEDs) and white OLEDs (WOLEDs) will be comprehensively surveyed and discussed.

  12. Human Intervention Study to Assess the Effects of Supplementation with Olive Leaf Extract on Peripheral Blood Mononuclear Cell Gene Expression

    PubMed Central

    Boss, Anna; Kao, Chi Hsiu-Juei; Murray, Pamela M.; Marlow, Gareth; Barnett, Matthew P. G.; Ferguson, Lynnette R.

    2016-01-01

    Olive leaf extract (OLE) has been used for many years for its putative health benefits, but, to date, scientific evidence for the basis of these effects has been weak. Although recent literature has described a link between ailments such as cardiovascular disease, diabetes and cancer and a protective effect of polyphenols in the OLE, the mode of action is still unclear. Here, we describe a double-blinded placebo (PBO)-controlled trial, in which gene expression profiles of peripheral blood mononuclear cells from healthy male volunteers (n = 29) were analysed to identify genes that responded to OLE, following an eight-week intervention with 20 mL daily consumption of either OLE or PBO. Differences between groups were determined using an adjusted linear model. Subsequent analyses indicated downregulation of genes important in inflammatory pathways, lipid metabolism and cancer as a result of OLE consumption. Gene expression was verified by real-time PCR for three genes (EGR1, COX-2 and ID3). The results presented here suggest that OLE consumption may result in health benefits through influencing the expression of genes in inflammatory and metabolic pathways. Future studies with a larger study group, including male and female participants, looking into direct effects of OLE on lipid metabolism and inflammation are warranted. PMID:27918443

  13. Optical Simulation and Optimization of Light Extraction Efficiency for Organic Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Su, Hang

    Current organic light emitting diodes (OLEDs) suffer from the low light extraction efficiency. In this thesis, novel OLED structures including photonic crystal, Fabry-Perot resonance cavity and hyperbolic metamaterials were numerically simulated and theoretically investigated. Finite-difference time-domain (FDTD) method was employed to numerically simulate the light extraction efficiency of various 3D OLED structures. With photonic crystal structures, a maximum of 30% extraction efficiency is achieved. A higher external quantum efficiency of 35% is derived after applying Fabry-Perot resonance cavity into OLEDs. Furthermore, different factors such as material properties, layer thicknesses and dipole polarizations and locations have been studied. Moreover, an upper limit for the light extraction efficiency of 80% is reached theoretically with perfect reflector and single dipole polarization and location. To elucidate the physical mechanism, transfer matrix method is introduced to calculate the spectral-hemispherical reflectance of the multilayer OLED structures. In addition, an attempt of using hyperbolic metamaterial in OLED has been made and resulted in 27% external quantum efficiency, due to the similar mechanism of wave interference as Fabry-Perot structure. The simulation and optimization methods and findings would facilitate the design of next generation, high-efficiency OLED devices.

  14. Olive (Olea europaea L.) leaf extract counteracts genotoxicity and oxidative stress of permethrin in human lymphocytes.

    PubMed

    Türkez, Hasan; Toğar, Başak

    2011-10-01

    The aim of this study was to investigate the protective effects of olive leaf extract (OLE) on genotoxicity and oxidative damage in cultured human blood cells treated with permethrin (PM) in the presence of a rat liver S9 mix containing cytochrome P 450 enzymes. Anti-genotoxic activities of OLE were studied using sister chromatid exchange (SCE) and chromosome aberration (CA) tests and furthermore total antioxidant capacity (TAC) and total oxidative status (TOS) were examined to determine the oxidative damage. Our results clearly revealed that treatment with PM (200 mg/l) alone increased SCE and CA rates and TOS level, decreased TAC level in cultured human blood cells. The OLE alone at the all tested doses did not induce any significant changes in the genotoxicity endpoint. However OLE leads to increases of plasma TAC level in vitro. OLE starts showing this positive effect at 100 mg/l. The combined treatment showed significant improvements in cytogenetic and biochemical parameters tested. Moreover, this improvement was more pronounced in the group received the high dose of the OLE. It could be concluded that the ethanol extract of OLE induced its genoprotective effect via the increase in the antioxidant capacity, inhibition of oxidative stress and scavenging of free radicals.

  15. High doses of olive leaf extract induce liver changes in mice.

    PubMed

    Arantes-Rodrigues, R; Henriques, A; Pires, M J; Colaço, B; Calado, A M; Rema, P; Colaço, A; Fernandes, T; De la Cruz, P L F; Lopes, C; Fidalgo-Gonçalves, L; Vilela, S; Pedrosa, T; Peixoto, F; Oliveira, P A

    2011-09-01

    Virtually ever since it was first commercialized in 1995, there have been several studies focusing on the use of olive leaf extract (OLE) as a natural therapy and its medical properties. The aim of this study was to investigate the effects of three different concentrations of OLE on the function of mice livers over the course of 14 weeks. Female ICR mice were divided into four groups, depending on OLE concentration used: 0%, 0.25%, 0.5%, and 0.75%. Alanine aminotransferase, alkaline phosphatase, total bilirubin and albumin serum concentrations were all measured. Histopathological changes of the liver were observed after haematoxylin and eosin, reticulin, and Masson's trichrome staining was carried out while liver mitochondrial bioenergetics were also evaluated. Alanine aminotransferase and alkaline phosphatase serum enzyme activities increased significantly in the groups in which 0.5% and 0.75% OLE concentrations were used. Histologically, all the groups exposed to OLE exhibited hyperplasia of the bile ducts, cholestasis, hepatocyte necrosis and inflammatory infiltrated. Hepatic fibrosis was observed in the groups featuring 0.5% and 0.75% OLE concentrations. The mitochondrial membrane potential, respiratory control ratio and ADP/O of samples from animals fed the higher OLE concentration was significantly decreased when compared to the control group.

  16. Protective effect of olive leaf extract on hippocampal injury induced by transient global cerebral ischemia and reperfusion in Mongolian gerbils.

    PubMed

    Dekanski, Dragana; Selaković, Vesna; Piperski, Vesna; Radulović, Zeljka; Korenić, Andrej; Radenović, Lidija

    2011-10-15

    The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral ischemia/reperfusion brain injury are well known. Mediterranean diet, rich in olive products, is associated with lower incidence of cardiovascular disease, cancer, inflammation and stroke. In this study, the possible neuroprotective effect of standardized dry olive leaf extract (OLE) is investigated for the first time. Transient global cerebral ischemia in Mongolian gerbils was used to investigate the OLE effects on different parameters of oxidative stress and neuronal damage in hippocampus. The biochemical measurements took place at different time points (80min, 2, 4 and 24h) after reperfusion. The effects of applied OLE were compared with effects of quercetin, a known neuroprotective plant flavonoid. Pretreatment with OLE (100mg/kg, per os) significantly inhibited production of superoxide and nitric oxide, decreased lipid peroxidation, and increased superoxide dismutase activity in all time points examined. Furthermore, OLE offered histological improvement as seen by decreasing neuronal damage in CA1 region of hippocampus. The effects of applied OLE were significantly higher than effects of quercetin (100mg/kg, per os). Our results indicate that OLE exerts a potent neuroprotective activity against neuronal damage in hippocampus after transient global cerebral ischemia, which could be attributed to its antioxidative properties.

  17. Anti-tumour effects of lanreotide for pancreatic and intestinal neuroendocrine tumours: the CLARINET open-label extension study

    PubMed Central

    Caplin, Martyn E; Pavel, Marianne; Ćwikła, Jarosław B; Phan, Alexandria T; Raderer, Markus; Sedláčková, Eva; Cadiot, Guillaume; Wolin, Edward M; Capdevila, Jaume; Wall, Lucy; Rindi, Guido; Langley, Alison; Martinez, Séverine; Gomez-Panzani, Edda; Ruszniewski, Philippe

    2016-01-01

    In the CLARINET study, lanreotide Autogel (depot in USA) significantly prolonged progression-free survival (PFS) in patients with metastatic pancreatic/intestinal neuroendocrine tumours (NETs). We report long-term safety and additional efficacy data from the open-label extension (OLE). Patients with metastatic grade 1/2 (Ki-67 ≤10%) non-functioning NET and documented baseline tumour-progression status received lanreotide Autogel 120 mg (n=101) or placebo (n=103) for 96 weeks or until death/progressive disease (PD) in CLARINET study. Patients with stable disease (SD) at core study end (lanreotide/placebo) or PD (placebo only) continued or switched to lanreotide in the OLE. In total, 88 patients (previously: lanreotide, n=41; placebo, n=47) participated: 38% had pancreatic, 39% midgut and 23% other/unknown primary tumours. Patients continuing lanreotide reported fewer adverse events (AEs) (all and treatment-related) during OLE than core study. Placebo-to-lanreotide switch patients reported similar AE rates in OLE and core studies, except more diarrhoea was considered treatment-related in OLE (overall diarrhoea unchanged). Median lanreotide PFS (core study randomisation to PD in core/OLE; n=101) was 32.8 months (95% CI: 30.9, 68.0). A sensitivity analysis, addressing potential selection bias by assuming that patients with SD on lanreotide in the core study and not entering the OLE (n=13) had PD 24 weeks after last core assessment, found median PFS remaining consistent: 30.8 months (95% CI: 30.0, 31.3). Median time to further PD after placebo-to-lanreotide switch (n=32) was 14.0 months (10.1; not reached). This OLE study suggests long-term treatment with lanreotide Autogel 120 mg maintained favourable safety/tolerability. CLARINET OLE data also provide new evidence of lanreotide anti-tumour benefits in indolent and progressive pancreatic/intestinal NETs. PMID:26743120

  18. High-resolution electrohydrodynamic jet printing of small-molecule organic light-emitting diodes.

    PubMed

    Kim, Kukjoo; Kim, Gyeomuk; Lee, Bo Ram; Ji, Sangyoon; Kim, So-Yun; An, Byeong Wan; Song, Myoung Hoon; Park, Jang-Ung

    2015-08-28

    The development of alternative organic light-emitting diode (OLED) fabrication technologies for high-definition and low-cost displays is an important research topic as conventional fine metal mask-assisted vacuum evaporation has reached its limit to reduce pixel sizes and manufacturing costs. Here, we report an electrohydrodynamic jet (e-jet) printing method to fabricate small-molecule OLED pixels with high resolution (pixel width of 5 μm), which significantly exceeds the resolutions of conventional inkjet or commercial OLED display pixels. In addition, we print small-molecule emitting materials which provide a significant advantage in terms of device efficiency and lifetime compared to those with polymers.

  19. Efficiency enhancement of blue phosphorescent organic light-emitting diodes using mixed electron transport layer

    NASA Astrophysics Data System (ADS)

    Yoo, Seung Il; Yoon, Ju-An; Kim, Nam Ho; Kim, Jin Wook; Lee, Ho Won; Kim, Young Kwan; He, Gufeng; Kim, Woo Young

    2015-01-01

    Blue phosphorescent organic light-emitting diodes (OLED) using mixed electron transport layer (ETL) were fabricated with the device structure of ITO/NPB/mCP:Firpic-8%/TPBi:BCP or TPBi:3TPYMB/Liq/Al to observe mixed ETL's influence on their electrical and optical characteristics. OLED device with mixed ETL of TPBi with BCP or 3TPYMB significantly improved its current efficiency to 30.4 and 34.2 cd/A comparing to 19.8 cd/A of single ETL with BCP only. We examined mixed ETL's capability of electron transport and triplet exciton confinement enhancing phosphorescent OLED's luminance and luminous efficiency.

  20. Microcavity organic light-emitting diodes for strongly directed pure red, green, and blue emissions

    NASA Astrophysics Data System (ADS)

    Tokito, Shizuo; Tsutsui, Tetsuo; Taga, Yasunori

    1999-09-01

    In this article we demonstrate strongly directed pure red, green, and blue emissions in the organic light-emitting diodes (OLEDs) with a planar microcavity defined by a pair of dielectric mirror and a metal mirror. By careful control of the cavity mode and the position of the resonance wavelength, the strong directionality in the forward direction as well as the spectral narrowing and the intensity enhancement are realized in the microcavity OLEDs. The intensity enhancements at the resonance wavelength are 1.5-5 compared to the noncavity OLEDs, and the chromaticity coordinates of the emission colors are the ideal primary colors. The experimental results are compared to theoretically calculated ones.

  1. Department of Energy Office of Energy Efficiency and Renewable Energy Solid State Lighting Core Technologies

    SciTech Connect

    Franky So; Paul Holloway; Jiangeng Xue

    2009-08-06

    The project objective is to demonstrate high efficiency white emitting OLED devices with a target luminous efficiency between 100 1m/W and 150 1m/W with integrated microcavity structure and down conversion phosphors. The main focus of this work will be on three areas: (1) demonstration of a 2X reduction in OLED device operating voltage by employing the appropriate dopants in the carrier transporting layers; (2) demonstration of a 3X light out-coupling efficiency enhancement by incorporating microcavity structure in the OLED devices; and (3) demonstration of a 2X down-conversion efficiency enhancement (from blue to white) using phosphors.

  2. Selective scattering polymer dispersed liquid crystal film for light enhancement of organic light emitting diode.

    PubMed

    Jiang, Jinghua; McGraw, Greg; Ma, Ruiqing; Brown, Julie; Yang, Deng-Ke

    2017-02-20

    We developed a novel light enhancing film for an organic light emitting diode (OLED) based on polymer dispersed liquid crystal (PDLC). In the film, the liquid crystal droplets are unidirectionally aligned along the film normal direction and exhibit selective scattering. The film scatters light emitted only in directions with large incident angles but not light emitted in directions with small incident angles. When the light is scattered, it changes propagation direction and exits the OLED. The PDLC film reduces the total internal reflection and thus can significantly increase the light efficiency of the OLED.

  3. Ultraviolet nanoimprinted polymer nanostructure for organic light emitting diode application

    NASA Astrophysics Data System (ADS)

    Jeon, Sohee; Kang, Jae-Wook; Park, Hyung-Dol; Kim, Jang-Joo; Youn, Jae R.; Shim, Jongyoup; Jeong, Jun-ho; Choi, Dae-Geun; Kim, Ki-Don; Altun, Ali Ozhan; Kim, Se-Heon; Lee, Yong-Hee

    2008-06-01

    Light extraction efficiency of a conventional organic light emitting diode (OLED) remains limited to approximately 20% as most of the emission is trapped in the waveguide and glass modes. An etchless simple method was developed to fabricate two-dimensional nanostructures on glass substrate directly by using ultraviolet (UV) curable polymer resin and UV nanoimprint lithography in order to improve output coupling efficiency of OLEDs. The enhancement of the light extraction was predicted by the three-dimensional finite difference time domain method. OLEDs integrated on nanoimprinted substrates enhanced electroluminance intensity by up to 50% compared to the conventional device.

  4. Lasing of Tamm states in highly efficient organic devices based on small-molecule organic semiconductors.

    PubMed

    Brückner, R; Lyssenko, V G; Hofmann, S; Leo, K

    2014-01-01

    We discuss approaches to increase the light outcoupling efficiency in organic microcavity (MC) lasers and organic light-emitting diodes (OLEDs). We find that the introduction of metals into the cavities leads to additional Tamm-plasmon polariton modes, while the corrugation of metal contacts, such as perforated μ-size holes or a periodic array of metal stripes, leads to 2D confinement of the cavity modes, which in turn reduces the lasing threshold in MCs. Furthermore, we elucidate light loss mechanisms in OLEDs and reveal how external dielectric layers and periodic gratings can be used to enhance outcoupling from the OLED cavity.

  5. Simple model-free estimation of orientation order parameters of vacuum-deposited and spin-coated amorphous films used in organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Sakai, Yoshiya; Shibata, Maki; Yokoyama, Daisuke

    2015-09-01

    Molecular orientation in organic light-emitting diodes (OLEDs) is now regarded as an important factor that affects device efficiency. However, methods to quantitatively estimate the degree of molecular orientation in OLEDs are currently limited, and they require constructing a model of an optical structure. Here, we propose a simple model-free method to estimate the orientation order parameters (S) of molecules in amorphous OLED films from their absorption spectra using the randomization of molecular orientation induced by heating. This method is used to quantitatively estimate the S values of vacuum-deposited and spin-coated films and clearly demonstrate the random orientation in the latter.

  6. Material degradation of liquid organic semiconductors analyzed by nuclear magnetic resonance spectroscopy

    SciTech Connect

    Fukushima, Tatsuya; Yamamoto, Junichi; Fukuchi, Masashi; Kaji, Hironori; Hirata, Shuzo; Jung, Heo Hyo; Adachi, Chihaya; Hirata, Osamu; Shibano, Yuki

    2015-08-15

    Liquid organic light-emitting diodes (liquid OLEDs) are unique devices consisting only of liquid organic semiconductors in the active layer, and the device performances have been investigated recently. However, the device degradation, especially, the origin has been unknown. In this study, we show that material degradation occurs in liquid OLEDs, whose active layer is composed of carbazole with an ethylene glycol chain. Nuclear magnetic resonance (NMR) experiments clearly exhibit that the dimerization reaction of carbazole moiety occurs in the liquid OLEDs during driving the devices. In contrast, cleavages of the ethylene glycol chain are not detected within experimental error. The dimerization reaction is considered to be related to the device degradation.

  7. Micro-pixel array of organic light-emitting diodes applying imprinting technique with a polymer replica

    NASA Astrophysics Data System (ADS)

    Park, Tae Hyun; Kim, Young Min; Park, Young Wook; Choi, Jin Hwan; Jeong, Jin-Wook; Dong, Ki Young; Choi, Kyung Cheol; Ju, Byeong-Kwon

    2009-08-01

    Efficient micro-pixel array of small molecule organic light-emitting diodes (OLEDs) has been fabricated by an imprinting technique which uses a polymer replica. To confirm the effect of the oxygen plasma for removing the residual layer, the performance of two kinds of OLEDs with varying thicknesses of resin as the micro-pixel array, have been compared. The measured results of the OLEDs have shown comparable device performances that are significantly characterized depending on the residues on the substrate. The performance of enhanced device has achieved efficiencies of 3.6 cd/A and 1.9 lm/W at 20 mA/cm2.

  8. Emotion Discrimination Using Spatially Compact Regions of Interest Extracted from Imaging EEG Activity

    PubMed Central

    Padilla-Buritica, Jorge I.; Martinez-Vargas, Juan D.; Castellanos-Dominguez, German

    2016-01-01

    Lately, research on computational models of emotion had been getting much attention due to their potential for understanding the mechanisms of emotions and their promising broad range of applications that potentially bridge the gap between human and machine interactions. We propose a new method for emotion classification that relies on features extracted from those active brain areas that are most likely related to emotions. To this end, we carry out the selection of spatially compact regions of interest that are computed using the brain neural activity reconstructed from Electroencephalography data. Throughout this study, we consider three representative feature extraction methods widely applied to emotion detection tasks, including Power spectral density, Wavelet, and Hjorth parameters. Further feature selection is carried out using principal component analysis. For validation purpose, these features are used to feed a support vector machine classifier that is trained under the leave-one-out cross-validation strategy. Obtained results on real affective data show that incorporation of the proposed training method in combination with the enhanced spatial resolution provided by the source estimation allows improving the performed accuracy of discrimination in most of the considered emotions, namely: dominance, valence, and liking. PMID:27489541

  9. Automatic and adaptive classification of electroencephalographic signals for brain computer interfaces.

    PubMed

    Rodríguez-Bermúdez, Germán; García-Laencina, Pedro J

    2012-11-01

    Extracting knowledge from electroencephalographic (EEG) signals has become an increasingly important research area in biomedical engineering. In addition to its clinical diagnostic purposes, in recent years there have been many efforts to develop brain computer interface (BCI) systems, which allow users to control external devices only by using their brain activity. Once the EEG signals have been acquired, it is necessary to use appropriate feature extraction and classification methods adapted to the user in order to improve the performance of the BCI system and, also, to make its design stage easier. This work introduces a novel fast adaptive BCI system for automatic feature extraction and classification of EEG signals. The proposed system efficiently combines several well-known feature extraction procedures and automatically chooses the most useful features for performing the classification task. Three different feature extraction techniques are applied: power spectral density, Hjorth parameters and autoregressive modelling. The most relevant features for linear discrimination are selected using a fast and robust wrapper methodology. The proposed method is evaluated using EEG signals from nine subjects during motor imagery tasks. Obtained experimental results show its advantages over the state-of-the-art methods, especially in terms of classification accuracy and computational cost.

  10. Analysis of EEG signals regularity in adults during video game play in 2D and 3D.

    PubMed

    Khairuddin, Hamizah R; Malik, Aamir S; Mumtaz, Wajid; Kamel, Nidal; Xia, Likun

    2013-01-01

    Video games have long been part of the entertainment industry. Nonetheless, it is not well known how video games can affect us with the advancement of 3D technology. The purpose of this study is to investigate the EEG signals regularity when playing video games in 2D and 3D modes. A total of 29 healthy subjects (24 male, 5 female) with mean age of 21.79 (1.63) years participated. Subjects were asked to play a car racing video game in three different modes (2D, 3D passive and 3D active). In 3D passive mode, subjects needed to wear a passive polarized glasses (cinema type) while for 3D active, an active shutter glasses was used. Scalp EEG data was recorded during game play using 19-channel EEG machine and linked ear was used as reference. After data were pre-processed, the signal irregularity for all conditions was computed. Two parameters were used to measure signal complexity for time series data: i) Hjorth-Complexity and ii) Composite Permutation Entropy Index (CPEI). Based on these two parameters, our results showed that the complexity level increased from eyes closed to eyes open condition; and further increased in the case of 3D as compared to 2D game play.

  11. Nonlinear time series analysis and clustering for jet axis identification in vertical turbulent heated jets.

    PubMed

    Charakopoulos, A K; Karakasidis, T E; Papanicolaou, P N; Liakopoulos, A

    2014-03-01

    In the present work we approach the hydrodynamic problem of discriminating the state of the turbulent fluid region as a function of the distance from the axis of a turbulent jet axis. More specifically, we analyzed temperature fluctuations in vertical turbulent heated jets where temperature time series were recorded along a horizontal line through the jet axis. We employed data from different sets of experiments with various initial conditions out of circular and elliptical shaped nozzles in order to identify time series taken at the jet axis, and discriminate them from those taken near the boundary with ambient fluid using nonconventional hydrodynamics methods. For each temperature time series measured at a different distance from jet axis, we estimated mainly nonlinear measures such as mutual information combined with descriptive statistics measures, as well as some linear and nonlinear dynamic detectors such as Hurst exponent, detrended fluctuation analysis, and Hjorth parameters. The results obtained in all cases have shown that the proposed methodology allows us to distinguish the flow regime around the jet axis and identify the time series corresponding to the jet axis in agreement with the conventional statistical hydrodynamic method. Furthermore, in order to reject the null hypothesis that the time series originate from a stochastic process, we applied the surrogate data method.

  12. Electronic structure of the polymer-cathode interface of an organic electroluminescent device investigated using operando hard x-ray photoelectron spectroscopy

    SciTech Connect

    Ikeuchi, J.; Hamamatsu, H.; Miyamoto, T.; Tanaka, S.; Yamashita, Y.; Yoshikawa, H.; Ueda, S.

    2015-08-28

    The electronic structure of a polymer-cathode interface of an operating organic light-emitting diode (OLED) was directly investigated using hard X-ray photoelectron spectroscopy (HAXPES). The potential distribution profile of the light-emitting copolymer layer as a function of the depth under the Al/Ba cathode layer in the OLED depended on the bias voltage. We found that band bending occurred in the copolymer of 9,9-dioctylfluorene (50%) and N-(4-(2-butyl)-phenyl)diphenylamine (F8-PFB) layer near the cathode at 0 V bias, while a linear potential distribution formed in the F8-PFB when a bias voltage was applied to the OLED. Direct observation of the built-in potential and that band bending formed in the F8-PFB layer in the operating OLED suggested that charges moved in the F8-PFB layer before electron injection from the cathode.

  13. Know Before You Go | NIH MedlinePlus the Magazine

    MedlinePlus

    ... check CDC's Travelers' Health page . Pack to prevent Insect repellent (look for DEET, picaridin, IR3535, OLE, or ... if you might have sex) Protect yourself Use insect repellent. Reapply as directed. Remember to apply sunscreen ...

  14. Adhesion and degradation of organic and hybrid organic-inorganic light-emitting devices

    SciTech Connect

    Momodu, D. Y.; Chioh, A. V.; Tong, T.; Zebaze Kana, M. G.; Soboyejo, W. O.

    2014-02-28

    This paper presents the results of a combined analytical, computational, and experimental study of adhesion and degradation of Organic Light Emitting Devices (OLEDs). The adhesion between layers that are relevant to OLEDs is studied using an atomic force microscopy technique. The interfacial failure mechanisms associated with blister formation in OLEDs and those due to the addition of TiO{sub 2} nanoparticles into the active regions are then elucidated using a combination of fracture mechanics, finite element modeling and experiments. The blisters observed in the models are shown to be consistent with the results from adhesion, interfacial fracture mechanics models, and prior reports of diffusion-assisted phenomena. The implications of the work are then discussed for the design of OLED structures with improved lifetimes and robustness.

  15. Development of finger-motion capturing device based on optical linear encoder.

    PubMed

    Li, Kang; Chen, I-Ming; Yeo, Song Huat; Lim, Chee Kian

    2011-01-01

    This article presents the design and validation of a wearable glove-based multifinger-motion capture device (SmartGlove), specifically focusing on the development of a new optical linear encoder (OLE). The OLE specially designed for this project is compact and lightweight and has low-power consumption. The characterization tests showed that the OLE's digital out put has good linearity and is accurate. The first prototype of SmartGlove, which uses 10 OLEs to capture the flexion/extension motion of the 14 finger joints, was constructed based on the multipoint-sensing method. A user study evaluated the SmartGlove using a standard protocol and found high repeatability and reliability in both the gripped and flat-hand positions compared with four other evaluated data gloves using the same protocol.

  16. Charge injection and accumulation in organic light-emitting diode with PEDOT:PSS anode

    SciTech Connect

    Weis, Martin; Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2015-04-21

    Organic light-emitting diode (OLED) displays using flexible substrates have many attractive features. Since transparent conductive oxides do not fit the requirements of flexible devices, conductive polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative. The charge injection and accumulation in OLED devices with PEDOT:PSS anodes are investigated and compared with indium tin oxide anode devices. Higher current density and electroluminescence light intensity are achieved for the OLED device with a PEDOT:PSS anode. The electric field induced second-harmonic generation technique is used for direct observation of temporal evolution of electric fields. It is clearly demonstrated that the improvement in the device performance of the OLED device with a PEDOT:PSS anode is associated with the smooth charge injection and accumulation.

  17. The mechanism of lifetime extension due to CuPc injection layer in organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Tutis, Eduard; Berner, Detlef F.; Zuppiroli, Libero

    2004-09-01

    The remarkable effect on lifetime improvement of copper phthalocianine (CuPc) coated indium tin oxide (ITO) anode of organic light emitting diodes (OLED's) is experimentally well approved. Also known are the electrode morphology, with and without CuPc coating, the energy levels of the used materials, important for charge injection and conduction, the carrier mobility etc. Based on this knowledge we suggest the model that explains the mechanism behind the lifetime improvement. We argue that the charge accumulation at the interface between the CuPc and the hole transport layer is responsible for screening out of the electric field variations leading to current density homogenization across the OLED surface. The variation of the injection field, introduced by electrode roughness, is estimated for typical indium tin oxide morphology used in OLED production. Without the CuPc hole injection layer a substantial current channeling occurs in OLED's, leading to accelerated device degradation.

  18. Luminance mechanisms in green organic light-emitting devices fabricated utilizing tris(8-hydroxyquinoline)aluminum/4,7-diphenyl-1, 10-phenanthroline multiple heterostructures acting as an electron transport layer.

    PubMed

    Choo, Dong Chul; Seo, Su Yul; Kim, Tae Whan; Jin, You Young; Seo, Ji Hyun; Kim, Young Kwan

    2010-05-01

    The electrical and the optical properties in green organic light-emitting devices (OLEDs) fabricated utilizing tris(8-hydroxyquinoline)aluminum (Alq3)/4,7-diphenyl-1,10-phenanthroline (BPhen) multiple heterostructures acting as an electron transport layer (ETL) were investigated. The operating voltage of the OLEDs with a multiple heterostructure ETL increased with increasing the number of the Alq3/BPhen heterostructures because more electrons were accumulated at the Alq3/BPhen heterointerfaces. The number of the leakage holes existing in the multiple heterostructure ETL of the OLEDs at a low voltage range slightly increased due to an increase of the internal electric field generated from the accumulated electrons at the Alq3/BPhen heterointerface. The luminance efficiency of the OLEDs with a multiple heterostructure ETL at a high voltage range became stabilized because the increase of the number of the heterointerface decreased the quantity of electrons accumulated at each heterointerface.

  19. 2,5-linked polyfluorenes for optoelectronic devices

    DOEpatents

    Cella, James Anthony; Shiang, Joseph John; Shanklin, Elliott West; Smigelski, Paul Michael

    2010-06-08

    Polyfluorene polymers and copolymers having substantial amounts (10-100%) of fluorenes coupled at the 2 and 5 positions of fluorene are useful as active layers in OLED devices where triplet energies >2.10 eV are required.

  20. 2,5-linked polyfluorenes for optoelectronic devices

    DOEpatents

    Cella, James Anthony; Shiang, Joseph John; Shanklin, Elliott West; Smigelski, Jr., Paul Michael

    2011-11-08

    Polyfluorene polymers and copolymers having substantial amounts (10-100%) of fluorenes coupled at the 2 and 5 positions of fluorene are useful as active layers in OLED devices where triplet energies >2.10 eV are required.

  1. Reliable thin film encapsulation for organic light emitting diodes grown by low-temperature atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Schneidenbach, D.; Winkler, T.; Hamwi, S.; Weimann, T.; Hinze, P.; Ammermann, S.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

    2009-06-01

    We report on highly efficient gas diffusion barriers for organic light emitting diodes (OLEDs). Nanolaminate (NL) structures composed of alternating Al2O3 and ZrO2 sublayers grown by atomic layer deposition at 80 °C are used to realize long-term stable OLED devices. While the brightness of phosphorescent p-i-n OLEDs sealed by a single Al2O3 layer drops to 85% of the initial luminance of 1000 cd/m2 after 1000 h of continuous operation, OLEDs encapsulated with the NL retain more than 95% of their brightness. An extrapolated device lifetime substantially in excess of 10 000 h can be achieved, clearly proving the suitability of the NLs as highly dense and reliable thin film encapsulation of sensitive organic electronic devices.

  2. Identification of Neuroprotective Spoxazomicin and Oxachelin Glycosides via Chemoenzymatic Glycosyl-Scanning.

    PubMed

    Zhang, Jianjun; Hughes, Ryan R; Saunders, Meredith A; Elshahawi, Sherif I; Ponomareva, Larissa V; Zhang, Yinan; Winchester, Sydney R; Scott, Samantha A; Sunkara, Manjula; Morris, Andrew J; Prendergast, Mark A; Shaaban, Khaled A; Thorson, Jon S

    2017-01-27

    The assessment of glycosyl-scanning to expand the molecular and functional diversity of metabolites from the underground coal mine fire-associated Streptomyces sp. RM-14-6 is reported. Using the engineered glycosyltransferase OleD Loki and a 2-chloro-4-nitrophenylglycoside-based screen, six metabolites were identified as substrates of OleD Loki, from which 12 corresponding metabolite glycosides were produced and characterized. This study highlights the first application of the 2-chloro-4-nitrophenylglycoside-based screen toward an unbiased set of unique microbial natural products and the first reported application of the 2-chloro-4-nitrophenylglycoside-based transglycosylation reaction for the corresponding preparative synthesis of target glycosides. Bioactivity analysis (including antibacterial, antifungal, anticancer, and EtOH damage neuroprotection assays) revealed glycosylation to attenuate the neuroprotective potency of 4, while glycosylation of the structurally related inactive spoxazomicin C (3) remarkably invoked neuroprotective activity.

  3. Plasma damage-free deposition of Al cathode on organic light-emitting devices by using mirror shape target sputtering

    SciTech Connect

    Kim, Han-Ki; Kim, D.-G.; Lee, K.-S.; Huh, M.-S.; Jeong, S.H.; Kim, K.I.; Kim, H.; Han, D.W.; Kwon, J.H.

    2004-11-08

    We report on the fabrication of plasma damage-free organic light-emitting devices (OLEDs) by using a mirror shape target sputtering (MSTS) technique. It is shown that OLEDs with Al cathode deposited by the MSTS show much lower leakage current (1x10{sup -5} mA/cm{sup 2}) at reverse bias of -6 V, compared to that (1x10{sup -1}-{approx}10{sup -2} mA/cm{sup 2} at -6 V) of OLEDs with Al cathodes grown by conventional dc magnetron sputtering. This indicates that there is no plasma damage, which is caused by the bombardment of energetic particles. This suggests that MSTS could be a useful plasma damage-free and low-temperature deposition technique for both top- and bottom-emitting OLEDs and flexible displays.

  4. An Identification of Interpersonal Skills for Building Army Civilian Leaders

    DTIC Science & Technology

    2006-09-01

    Development Course MBTI Myers-Briggs Type Indicator MDC Manager Development Course NSPS National Security Personnel System O Officer OLE...face communication, public speaking, in writing, verbally, and through briefings. The Myers-Briggs Type Indicator ( MBTI ) personality inventory

  5. Super color purity green organic light-emitting diodes with ZrO2/zircone nanolaminates as a distributed Bragg reflector deposited by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Zhang, Hao; Zheng, Yanqiong; Wei, Mengjie; Ding, He; Wei, Bin; Zhang, Zhilin

    2017-01-01

    ZrO2/zircone nanolaminate thin films fabricated by atomic layer deposition were used for a distributed Bragg reflector (DBR) in green organic light-emitting diodes (OLEDs). It is found that the novel ZrO2/zircone DBR structure significantly improves the light purity of green OLEDs without interfering with intrinsic electroluminescence properties. The full width at half maximum (FWHM) of the EL spectral band for the green OLEDs decreases with respect to increasing the ZrO2/zircone pairs. The FWHMs of OLEDs with 0, 2, 4, and 6 pairs of ZrO2/zircone layers are 72 nm, 48 nm, 24 nm, and 12 nm, respectively. A super-narrow FWHM of 12 nm is achieved by using six pairs of the DBR structure. The EQE is increased from 10.7% to 16.1% with four pairs of ZrO2/zircone layers.

  6. 2,5-linked polyfluorenes for optoelectronic devices

    DOEpatents

    Cella, James Anthony; Shiang, Joseph John; Shanklin, Elliott West; Smigelski, Paul Michael

    2009-12-22

    Polyfluorene polymers and copolymers having substantial amounts (10-100%) of fluorenes coupled at the 2 and 5 positions of fluorene are useful as active layers in OLED devices where triplet energies >2.10 eV are required.

  7. 2,5-linked polyfluorenes for optoelectronic devices

    DOEpatents

    Cella, James Anthony; Shiang, Joseph John; Shanklin, Elliott West; Smigelski, Jr, Paul Michael

    2011-06-28

    Polyfluorene polymers and copolymers having substantial amounts (10-100%) of fluorenes coupled at the 2 and 5 positions of fluorene are useful as active layers in OLED devices where triplet energies >2.10 eV are required.

  8. Red-emitting fluorescent organic light emitting diodes with low sensitivity to self-quenching

    NASA Astrophysics Data System (ADS)

    Forget, S.; Chenais, S.; Tondelier, D.; Geffroy, B.; Gozhyk, I.; Lebental, M.; Ishow, E.

    2010-09-01

    Concentration quenching is a major impediment to efficient organic light-emitting devices (OLEDs). We herein report on OLEDs based on a fluorescent amorphous red-emitting starbust triarylamine molecule [4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene, named FVIN], exhibiting a very small sensitivity to concentration quenching. OLEDs are fabricated with various doping levels of FVIN into Alq3, and show a remarkably stable external quantum efficiency of 1.5% for doping rates ranging from 5% up to 40%, which strongly relaxes the technological constraints on the doping accuracy. An efficiency of 1% is obtained for a pure undoped active region, along with deep red emission (x=0.6; y=0.35 in the Commission Internationale de l'Energie (CIE) coordinates). A comparison of FVIN with the archetypal 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye is presented in an identical multilayer OLED structure.

  9. Efficient Light Extraction from Organic Light-Emitting Diodes Using Plasmonic Scattering Layers

    SciTech Connect

    Rothberg, Lewis

    2012-11-30

    Our project addressed the DOE MYPP 2020 goal to improve light extraction from organic light-emitting diodes (OLEDs) to 75% (Core task 6.3). As noted in the 2010 MYPP, “the greatest opportunity for improvement is in the extraction of light from [OLED] panels”. There are many approaches to avoiding waveguiding limitations intrinsic to the planar OLED structure including use of textured substrates, microcavity designs and incorporating scattering layers into the device structure. We have chosen to pursue scattering layers since it addresses the largest source of loss which is waveguiding in the OLED itself. Scattering layers also have the potential to be relatively robust to color, polarization and angular distributions. We note that this can be combined with textured or microlens decorated substrates to achieve additional enhancement.

  10. Evaluation of an organic light-emitting diode display for precise visual stimulation.

    PubMed

    Ito, Hiroyuki; Ogawa, Masaki; Sunaga, Shoji

    2013-06-11

    A new type of visual display for presentation of a visual stimulus with high quality was assessed. The characteristics of an organic light-emitting diode (OLED) display (Sony PVM-2541, 24.5 in.; Sony Corporation, Tokyo, Japan) were measured in detail from the viewpoint of its applicability to visual psychophysics. We found the new display to be superior to other display types in terms of spatial uniformity, color gamut, and contrast ratio. Changes in the intensity of luminance were sharper on the OLED display than those on a liquid crystal display. Therefore, such OLED displays could replace conventional cathode ray tube displays in vision research for high quality stimulus presentation. Benefits of using OLED displays in vision research were especially apparent in the fields of low-level vision, where precise control and description of the stimulus are needed, e.g., in mesopic or scotopic vision, color vision, and motion perception.

  11. Phosphorescent dye-based supramolecules for high-efficiency organic light-emitting diodes.

    PubMed

    Kim, Kwon-Hyeon; Lee, Sunghun; Moon, Chang-Ki; Kim, Sei-Yong; Park, Young-Seo; Lee, Jeong-Hwan; Woo Lee, Jin; Huh, June; You, Youngmin; Kim, Jang-Joo

    2014-09-10

    Organic light-emitting diodes (OLEDs) are among the most promising organic semiconductor devices. The recently reported external quantum efficiencies (EQEs) of 29-30% for green and blue phosphorescent OLEDs are considered to be near the limit for isotropically oriented iridium complexes. The preferred orientation of transition dipole moments has not been thoroughly considered for phosphorescent OLEDs because of the lack of an apparent driving force for a molecular arrangement in all but a few cases, even though horizontally oriented transition dipoles can result in efficiencies of over 30%. Here we use quantum chemical calculations to show that the preferred orientation of the transition dipole moments of heteroleptic iridium complexes (HICs) in OLEDs originates from the preferred direction of the HIC triplet transition dipole moments and the strong supramolecular arrangement within the co-host environment. We also demonstrate an unprecedentedly high EQE of 35.6% when using HICs with phosphorescent transition dipole moments oriented in the horizontal direction.

  12. 50 CFR 660.11 - General definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ....11 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fishery Science Center, National Marine Fisheries Service, Seattle, Washington. Office of Law Enforcement or OLE refers to the National Marine Fisheries Service, Office of Law Enforcement, Northwest...

  13. Effects of the interfacial charge injection properties of silver nanowire transparent conductive electrodes on the performance of organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hoon; Triambulo, Ross E.; Park, Jin-Woo

    2017-03-01

    We investigated the charge injection properties of silver nanowire networks (AgNWs) in a composite-like structure with poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate) (PEDOT:PSS). The composite films acted as the anodes and hole transport layers (HTLs) in organic light-emitting diodes (OLEDs). The current density (J)-voltage (V)-luminance (L) characteristics and power efficiency (ɛ) of the OLEDs were measured to determine their electrical and optical properties. The charge injection properties of the AgNWs in the OLEDs during operation were characterized via impedance spectroscopy (IS) by determining the variations in the capacitances (C) of the devices with respect to the applied V and the corresponding frequency (f). All measured results were compared with results for OLEDs fabricated on indium tin oxide (ITO) anodes. The OLEDs on AgNWs showed lower L and ɛ values than the OLEDs on ITO. It was also observed that AgNWs exhibit excellent charge injection properties and that the interfaces between the AgNWs and the HTL have very small charge injection barriers, resulting in an absence of charge carrier traps when charges move across these interfaces. However, in the AgNW-based OLED, there was a large mismatch in the number of injected holes and electrons. Furthermore, the highly conductive electrical paths of the AgNWs in the composite-like AgNW and PEDOT:PSS structure allowed a large leakage current of holes that did not participate in radiative recombination with the electrons; consequently, a lower ɛ was observed for the AgNW-based OLEDs than for the ITO-based OLEDs. To match the injection of electrons by the electron transport layer (ETL) in the AgNW-based OLED with that of holes by the AgNW/PEDOT:PSS composite anode, the electron injection barrier of the ETL was decreased by using the low work function polyethylenimine ethoxylated (PEIE) doped with n-type cesium carbonate (Cs2CO3). With the doped-PEIE, the performance of the AgNW-based OLED was

  14. Organic light emitting device structures for obtaining chromaticity stability

    DOEpatents

    Tung, Yeh-Jiun; Lu, Michael; Kwong, Raymond C.

    2005-04-26

    The present invention relates to organic light emitting devices (OLEDs). The devices of the present invention are efficient white or multicolored phosphorescent OLEDs which have a high color stability over a wide range of luminances. The devices of the present invention comprise an emissive region having at least two emissive layers, with each emissive layer comprising a different host and emissive dopant, wherein at least one of the emissive dopants emits by phosphorescence.

  15. Organic light emitting device structure for obtaining chromaticity stability

    DOEpatents

    Tung, Yeh-Jiun; Ngo, Tan

    2007-05-01

    The present invention relates to organic light emitting devices (OLEDs). The devices of the present invention are efficient white or multicolored phosphorescent OLEDs which have a high color stability over a wide range of luminances. The devices of the present invention comprise an emissive region having at least two emissive layers, with each emissive layer comprising a different host and emissive dopant, wherein at least one of the emissive dopants emits by phosphorescence.

  16. A simple strategy for glycosyltransferase-catalyzed aminosugar nucleotide synthesis.

    PubMed

    Zhang, Jianjun; Singh, Shanteri; Hughes, Ryan R; Zhou, Maoquan; Sunkara, Manjula; Morris, Andrew J; Thorson, Jon S

    2014-03-21

    A set of 2-chloro-4-nitrophenyl glucosamino-/xylosaminosides were synthesized and assessed as potential substrates in the context of glycosyltransferase-catalyzed formation of the corresponding UDP/TDP-α-D-glucosamino-/xylosaminosugars and in single-vessel model transglycosylation reactions. This study highlights a robust platform for aminosugar nucleotide synthesis and reveals OleD Loki to be a proficient catalyst for U/TDP-aminosugar synthesis and utilization

  17. DNA Bases Thymine and Adenine in Bio-Organic Light Emitting Diodes

    DTIC Science & Technology

    2014-11-24

    DNA Bases Thymine and Adenine in Bio-Organic Light Emitting Diodes Eliot F. Gomez1, Vishak Venkatraman1, James G. Grote2 & Andrew J. Steckl1...45433-7707 USA. We report on the use of nucleic acid bases (NBs) in organic light emitting diodes (OLEDs). NBs are small molecules that are the basic...polymer has been a frequent natural material integrated in electronic devices. DNA has been used in organic light - emitting diodes (OLEDs)4,5,7–14

  18. Organic Polymer Light Emitting Display for Digital Mammography

    DTIC Science & Technology

    2003-03-01

    displays (AM-OLEDs) based on a three hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) pixel electrode circuit that supplies a continuous...can prevent the development of the high-resolution displays. Also so far all AM-OLEDs are based on poly-crystalline silicon (poly- Si) TFT technology... PEDOT ) doped with poly(styrenesulfonate) (PSS) and green light-emitting poly (fluorene) copolymer were used for HIL and LEL materials, respectively

  19. Cloning and expression of Aca f 1: a new allergen of Acacia farnesiana pollen

    PubMed Central

    Khosravi, Gholam Reza; Morakabati, Payam; Akbari, Bahareh; Dousti, Fatemeh

    2016-01-01

    Acacia farnesiana is the main source of allergenic pollen and one of the most important causes of respiratory allergic disease in tropical and subtropical regions of the world. The purpose of this study was to produce a recombinant variety of allergenic Ole e 1-like protein from the pollen of this tree. To predict its allergenic cross-reactivity with other members of the Ole e 1-like protein family of common allergenic plants, the nucleotide sequence homology of the Acacia Ole e 1-like protein was evaluated. Amplification of cDNA strands encoding Acacia Ole e 1-like protein was performed by polymerase chain reaction (PCR) and sequenced. Following expression in Escherichia coli using the pET-21b(+) vector, the recombinant protein was purified using metal-affinity chromatography. IgE-binding competence of purified recombinant Ole e 1- like protein (rAca f 1) was analysed by immunoassay using 25 sera collected from Acacia pollen-sensitised patients. Nucleotide sequencing revealed an open reading frame of 453 bp encoding 150 amino acid residues that belonged to the Ole e 1-like protein family, and 11 patients (44%) had considerable specific IgE levels for the rAca f 1. Immunodetection and inhibition assays indicated that the purified rAca f 1 may be the same as that in the crude extract. Aca f 1, the second allergen from Acacia pollen, was identified as a member of the family of Ole e 1-like protein. A high degree of homology was found among amino acid sequences of Aca f 1 and several allergenic members of Ole e 1-like protein family. PMID:27833445

  20. Cloning and expression of Aca f 1: a new allergen of Acacia farnesiana pollen.

    PubMed

    Khosravi, Gholam Reza; Assarehzadegan, Mohammad-Ali; Morakabati, Payam; Akbari, Bahareh; Dousti, Fatemeh

    2016-01-01

    Acacia farnesiana is the main source of allergenic pollen and one of the most important causes of respiratory allergic disease in tropical and subtropical regions of the world. The purpose of this study was to produce a recombinant variety of allergenic Ole e 1-like protein from the pollen of this tree. To predict its allergenic cross-reactivity with other members of the Ole e 1-like protein family of common allergenic plants, the nucleotide sequence homology of the Acacia Ole e 1-like protein was evaluated. Amplification of cDNA strands encoding Acacia Ole e 1-like protein was performed by polymerase chain reaction (PCR) and sequenced. Following expression in Escherichia coli using the pET-21b(+) vector, the recombinant protein was purified using metal-affinity chromatography. IgE-binding competence of purified recombinant Ole e 1- like protein (rAca f 1) was analysed by immunoassay using 25 sera collected from Acacia pollen-sensitised patients. Nucleotide sequencing revealed an open reading frame of 453 bp encoding 150 amino acid residues that belonged to the Ole e 1-like protein family, and 11 patients (44%) had considerable specific IgE levels for the rAca f 1. Immunodetection and inhibition assays indicated that the purified rAca f 1 may be the same as that in the crude extract. Aca f 1, the second allergen from Acacia pollen, was identified as a member of the family of Ole e 1-like protein. A high degree of homology was found among amino acid sequences of Aca f 1 and several allergenic members of Ole e 1-like protein family.

  1. Organic Thin Film Devices for Displays and Lighting

    NASA Astrophysics Data System (ADS)

    Weiss, Oliver J.; Krause, Ralf; Paetzold, Ralph

    Organic materials can be used for fabrication of, e.g., electronic circuits, solar cells, light sensors, memory cells and light emitting diodes. Especially organic light emitting diodes (OLEDs) are increasingly attractive because of their huge market potential. The feasibility of efficient OLEDs was first shown in 1987 [3]. Only about ten years later the first product, a display for car radios, entered the market. Today monochrome and full colour OLED-displays can be found in many applications replacing established flat panel display technologies like TFT-LCDs. This substitution is a consequence of the outstanding attributes of OLED technology: Organic light emitting displays are self-emissive, thin, video capable and in addition they show a wide temperature operation range and allow a viewing angle of nearly 180 degree in conjunction with a low power consumption. As performance has steadily increased over the last years, today OLEDs are also under investigation as next generation light source. In contrast to inorganic LEDs, they can be built as flat 2-dimensional light sources that are lightweight, colour tunable, and potentially cheap. This will open up new degrees of freedom in design leading also to completely new applications. In this contribution we will have a brief view on the history of organic electroluminescent materials before we introduce the basic principles of OLEDs with a focus on the physical processes leading to light generation in thin organic films. Along with an overview of different concepts and technologies used to build OLEDs, the current status of OLED development will be illustrated. The last part focuses on the challenges that have to be overcome to enable a sustainable success in the display and lighting markets.

  2. Efficient HOMO-LUMO separation by multiple resonance effect toward ultrapure blue thermally activated delayed fluorescence

    NASA Astrophysics Data System (ADS)

    Hatakeyama, Takuji; Ikuta, Toshiaki; Shiren, Kazushi; Nakajima, Kiichi; Nomura, Shintaro; Ni, Jingping

    2016-09-01

    Organic light-emitting diodes (OLEDs) play an important role in the new generation of flat-panel displays. Conventional OLEDs employing fluorescent materials together with triplet-triplet annihilation suffer from a relatively low internal quantum efficiency (IQE) of 62.5%. On the other hand, the IQE of OLEDs employing phosphorescent or thermally activated delayed fluorescence (TADF) materials can reach 100%. However, these materials exhibit very broad peaks with a full-width at half-maximum (FWHM) of 70-100 nm and cannot satisfy the color-purity requirements for displays. Therefore, the latest commercial OLED displays employ blue fluorescent materials with a relatively low IQE, and efficient blue emitters with a small FWHM are highly needed. In our manuscript, we present organic molecules that exhibit ultrapure blue fluorescence based on TADF. These molecules consist of three benzene rings connected by one boron and two nitrogen atoms, which establish a rigid polycyclic framework and significant localization of the highest occupied and lowest unoccupied molecular orbitals by a multiple resonance effect. An OLED device based on the new emitter exhibits ultrapure blue emission at 467 nm with an FWHM of 28 nm, Commission Internationale de l'Eclairage (CIE) coordinates of (0.12, 0.13), and an IQE of 100%, which represent record-setting performance for blue OLED devices.

  3. Biochemical and histological effects of feeding thermally oxidized rapeseed oil and lard to rats.

    PubMed Central

    Gabriel, H G; Alexander, J C; Valli, V E

    1977-01-01

    Four groups of weanling rats were fed semisynthetic diets containing 15 percent by weight of dietary fats for 28 days. Two groups received thermally oxidized low-erucic acid rapeseed oil (OLE) or lard (OLA) and the other two groups received the respective fresh fats (FLE, FLA) as controls. Average daily feed consumption and feed efficiency were not affected by either OLE or OLA, however final body weights were depressed by the OLA in the diet. The relative heart weights and heart total lipids were significantly increased in both the OLE and OLA groups. A majority of the animals in both the OLE and OLA groups exhibited various gross symptoms attributable to heated fat toxicity such as seborrhea, diarrhea and polyuria. Excessive hair loss was noted in all the animals fed the heated fats. Tissue fatty acid changes due to OLA were confined largely to the polar liver lipids, whereas OLE produced dramatic changes in both the neutral heart lipids as well as in the neutral and polar liver lipids. Histological evaluation of the hearts, livers and kidneys indicated that OLA was very injurious to the kidneys, whereas OLE caused greater damage to both the hearts and livers. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. PMID:832196

  4. Enhancing light out-coupling of organic light-emitting devices using indium tin oxide-free low-index transparent electrodes

    SciTech Connect

    Huang, Yi-Hsiang; Lu, Chun-Yang; Tsai, Shang-Ta; Tsai, Yu-Tang; Chen, Chien-Yu; Tsai, Wei-Lung; Lin, Chun-Yu; Chang, Hong-Wei; Lee, Wei-Kai; Jiao, Min; Wu, Chung-Chih

    2014-05-05

    With its increasing and sufficient conductivity, the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been capable of replacing the widely used but less cost-effective indium tin oxides (ITOs) as alternative transparent electrodes for organic light-emitting devices (OLEDs). Intriguingly, PEDOT:PSS also possesses an optical refractive index significantly lower than those of ITO and typical organic layers in OLEDs and well matching those of typical OLED substrates. Optical simulation reveals that by replacing ITO with such a low-index transparent electrode, the guided modes trapped within the organic/ITO layers in conventional OLEDs can be substantially suppressed, leading to more light coupled into the substrate than the conventional ITO device. By applying light out-coupling structures onto outer surfaces of substrates to effectively extract radiation into substrates, OLEDs using such low-index transparent electrodes achieve enhanced optical out-coupling and external quantum efficiencies in comparison with conventional OLEDs using ITO.

  5. Exciplex-Forming Co-Host-Based Red Phosphorescent Organic Light-Emitting Diodes with Long Operational Stability and High Efficiency.

    PubMed

    Lee, Jeong-Hwan; Shin, Hyun; Kim, Jae-Min; Kim, Kwon-Hyeon; Kim, Jang-Joo

    2017-02-01

    The use of exciplex forming cohosts and phosphors incredibly boosts the efficiency of organic light-emitting diodes (OLEDs) by providing a barrier-free charge injection into an emitting layer and a broad recombination zone. However, most of the efficient OLEDs based on the exciplex forming cohosts has suffered from the short operational lifetime. Here, we demonstrated phosphorescent OLEDs (PhOLEDs) having both high efficiency and long lifetime by using a new exciplex forming cohost composed of N,N'-diphenyl-N,N'-bis(1,1'-biphenyl)-4,4'-diamine (NPB) and (1,3,5-triazine-2,4,6-triyl)tris(benzene-3,1-diyl))tris(diphenylphosphine oxide) (PO-T2T). The red-emitting PhOLEDs using the exciplex forming cohost achieved a maximum external quantum efficiency (EQE) of 34.1% and power efficiency of 62.2 lm W(1-) with low operating voltages and low efficiency roll-offs. More importantly, the device demonstrated a long lifetime around 2249 h from 1000 cd m(-2) to 900 cd m(-2) (LT90) under a continuous flow of constant current. The efficiencies of the devices are the highest for red OLEDs with an LT90 > 1000 h.

  6. High-resolution electrohydrodynamic jet printing of small-molecule organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kim, Kukjoo; Kim, Gyeomuk; Lee, Bo Ram; Ji, Sangyoon; Kim, So-Yun; An, Byeong Wan; Song, Myoung Hoon; Park, Jang-Ung

    2015-08-01

    The development of alternative organic light-emitting diode (OLED) fabrication technologies for high-definition and low-cost displays is an important research topic as conventional fine metal mask-assisted vacuum evaporation has reached its limit to reduce pixel sizes and manufacturing costs. Here, we report an electrohydrodynamic jet (e-jet) printing method to fabricate small-molecule OLED pixels with high resolution (pixel width of 5 μm), which significantly exceeds the resolutions of conventional inkjet or commercial OLED display pixels. In addition, we print small-molecule emitting materials which provide a significant advantage in terms of device efficiency and lifetime compared to those with polymers.The development of alternative organic light-emitting diode (OLED) fabrication technologies for high-definition and low-cost displays is an important research topic as conventional fine metal mask-assisted vacuum evaporation has reached its limit to reduce pixel sizes and manufacturing costs. Here, we report an electrohydrodynamic jet (e-jet) printing method to fabricate small-molecule OLED pixels with high resolution (pixel width of 5 μm), which significantly exceeds the resolutions of conventional inkjet or commercial OLED display pixels. In addition, we print small-molecule emitting materials which provide a significant advantage in terms of device efficiency and lifetime compared to those with polymers. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03034j

  7. Hybrid metal grid-polymer-carbon nanotube electrodes for high luminance organic light emitting diodes.

    PubMed

    Sam, F Laurent M; Dabera, G Dinesha M R; Lai, Khue T; Mills, Christopher A; Rozanski, Lynn J; Silva, S Ravi P

    2014-08-29

    Organic light emitting diodes (OLEDs) incorporating grid transparent conducting electrodes (TCEs) with wide grid line spacing suffer from an inability to transfer charge carriers across the gaps in the grids to promote light emission in these areas. High luminance OLEDs fabricated using a hybrid TCE composed of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS PH1000) or regioregular poly(3-hexylthiophene)-wrapped semiconducting single-walled carbon nanotubes (rrP3HT-SWCNT) in combination with a nanometre thin gold grid are reported here. OLEDs fabricated using the hybrid gold grid/PH1000 TCE have a luminance of 18 000 cd m(-2) at 9 V; the same as the reference indium tin oxide (ITO) OLED. The gold grid/rrP3HT-SWCNT OLEDs have a lower luminance of 8260 cd m(-2) at 9 V, which is likely due to a rougher rrP3HT-SWCNT surface. These results demonstrate that the hybrid gold grid/PH1000 TCE is a promising replacement for ITO in future plastic electronics applications including OLEDs and organic photovoltaics. For applications where surface roughness is not critical, e.g. electrochromic devices or discharge of static electricity, the gold grid/rrP3HT-SWCNT hybrid TCE can be employed.

  8. Patternless light outcoupling enhancement method for top-emission organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kim, Doo-Hoon; Lee, Ho-Nyeon

    2016-11-01

    An increase of 65% in the luminous flux of a top-emission organic light-emitting diode (TE-OLED) was obtained by fabricating a stacked N,N‧-bis(naphthalen-1-yl)-N,N‧-bis(phenyl)benzidine (NPB) (0.2 µm)/CaF2 (2.5 µm) light outcoupling layer on the TE-OLED. The high-refractive-index NPB layer extracted the trapped light energy in the TE-OLED for input into the light outcoupling layer and protected the top cathode of the TE-OLED from damage due to the CaF2 layer. The surface morphology of the CaF2 layer had an irregular shape consisting of randomly dispersed pyramids; the irregular structure scattered the waveguide mode energy into air. By combining the effects of the NPB and CaF2 layers, the external quantum efficiency of the TE-OLED was increased significantly. The light outcoupling layer can be fabricated using a thermal evaporation process without patterning and, hence, provides a practical solution for the enhancement of TE-OLED light outcoupling using a patternless fabrication process.

  9. Efficient Color-Stable Inverted White Organic Light-Emitting Diodes with Outcoupling-Enhanced ZnO Layer.

    PubMed

    Zhao, Xin-Dong; Li, Yan-Qing; Xiang, Heng-Yang; Zhang, Yi-Bo; Chen, Jing-De; Xu, Lu-Hai; Tang, Jian-Xin

    2017-01-25

    Inverted organic light-emitting diode (OLED) has attracted extensive attention due to the demand in active-matrix OLED display panels as its geometry enables the direct connection with n-channel transistor backplane on the substrate. One key challenge of high-performance inverted OLED is an efficient electron-injection layer with superior electrical and optical properties to match the indium tin oxide cathode on substrate. We here propose a synergistic electron-injection architecture using surface modification of ZnO layer to simultaneously promote electron injection into organic emitter and enhance out-coupling of waveguided light. An efficient inverted white OLED is realized by introducing the nanoimprinted aperiodic nanostructure of ZnO for broadband and angle-independent light out-coupling and inserting an n-type doped interlayer for energy level tuning and injection barrier lowering. As a result, the optimized inverted white OLEDs have an external quantum efficiency of 42.4% and a power efficiency of 85.4 lm W(1-), which are accompanied by the superiority of angular color stability over the visible wavelength range. Our results may inspire a promising approach to fabricate high-efficiency inverted OLEDs for large-scale display panels.

  10. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model.

    PubMed

    Achour, Imène; Arel-Dubeau, Anne-Marie; Renaud, Justine; Legrand, Manon; Attard, Everaldo; Germain, Marc; Martinoli, Maria-Grazia

    2016-08-09

    Parkinson's disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE's ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model.

  11. Effects of olive leaves extract on LDL oxidation induced-CuSO(4) in vitro.

    PubMed

    Ahmadvand, Hassan; Bagheri, Shahrokh; Khosrobeigi, Ali; Boshtam, Maryam; Abdolahpour, Foad

    2012-07-01

    Oxidation of low-density lipoprotein (LDL) has been strongly implicated in the pathogenesis of atherosclerosis. The use of some natural antioxidant and herbal medicine may lead to the inhibition of production of oxidized LDL and may decrease both the development and the progression of atherosclerosis. The aim of this study was to investigate the effects of Olive leaves ethanol extract (OLE) on LDL oxidation induced-CuSO(4) quantitatively in vitro. Low-density lipoprotein was incubated with CuSO(4) and the formation of conjugated dienes and thiobarbituric acid reactive substances (TBARS). Inhibition of this Cu-induced oxidation was studied in the presence of vitamin E and various concentration of OLE. It was demonstrated that OLE reduced the formation of conjugated dienes and TBARS of LDL against oxidation in vitro (p<0.05). The inhibitory effects of the OLE on LDL oxidation were dose-dependent at concentrations ranging from (2μg/ml) to (200μg/ml). Moreover, we compared effects of OLE on LDL oxidation with vitamin E as positive control. This study showed that OLE is a source of potent antioxidants and prevented the oxidation of LDL in vitro and it may be suitable for use in food and pharmaceutical applications.

  12. Analytical equation for the motion picture response time of display devices

    NASA Astrophysics Data System (ADS)

    Peng, Fenglin; Chen, Haiwei; Gou, Fangwang; Lee, Yun-Han; Wand, Michael; Li, Ming-Chun; Lee, Seok-Lyul; Wu, Shin-Tson

    2017-01-01

    Motion picture response time (MPRT) affects the image blurs of thin-film transistor (TFT) liquid crystal displays and organic light emitting diode (OLED) displays. We derive an analytical equation to correlate MPRT with the liquid crystal (LC)/OLED response time and TFT frame rate. Good agreement between our physical model and experimental results is obtained. Based on our model, we find that if the LC's response time is 2 ms or less, then its MPRT is nearly the same as that of OLED, even if OLED's response time is assumed to be 0. To achieve MPRT comparable to OLEDs, we developed an ultra-low viscosity LC mixture for the vertical alignment mode operation. The measured average gray-to-gray response time is 0.93 ms, and its MPRT at 120 Hz is 6.88 ms. In comparison, OLED's MPRT is 6.67 ms. To further shorten MPRT, we could either increase the frame rate or reduce the backlight duty ratio. Pros and cons of these approaches are discussed.

  13. Enhanced light extraction from organic light-emitting devices using a sub-anode grid (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Qu, Yue; Slootsky, Michael; Forrest, Stephen

    2015-10-01

    We demonstrate a method for extracting waveguided light trapped in the organic and indium tin oxide layers of bottom emission organic light emitting devices (OLEDs) using a patterned planar grid layer (sub-anode grid) between the anode and the substrate. The scattering layer consists of two transparent materials with different refractive indices on a period sufficiently large to avoid diffraction and other unwanted wavelength-dependent effects. The position of the sub-anode grid outside of the OLED active region allows complete freedom in varying its dimensions and materials from which it is made without impacting the electrical characteristics of the device itself. Full wave electromagnetic simulation is used to study the efficiency dependence on refractive indices and geometric parameters of the grid. We show the fabrication process and characterization of OLEDs with two different grids: a buried sub-anode grid consisting of two dielectric materials, and an air sub-anode grid consisting of a dielectric material and gridline voids. Using a sub-anode grid, substrate plus air modes quantum efficiency of an OLED is enhanced from (33+/-2)% to (40+/-2)%, resulting in an increase in external quantum efficiency from (14+/-1)% to (18+/-1)%, with identical electrical characteristics to that of a conventional device. By varying the thickness of the electron transport layer (ETL) of sub-anode grid OLEDs, we find that all power launched into the waveguide modes is scattered into substrate. We also demonstrate a sub-anode grid combined with a thick ETL significantly reduces surface plasmon polaritons, and results in an increase in substrate plus air modes by a >50% compared with a conventional OLED. The wavelength, viewing angle and molecular orientational independence provided by this approach make this an attractive and general solution to the problem of extracting waveguided light and reducing plasmon losses in OLEDs.

  14. A major allergen from pollen defines a novel family of plant proteins and shows intra- and interspecies [correction of interspecie] cross-reactivity.

    PubMed

    Barral, Patricia; Batanero, Eva; Palomares, Oscar; Quiralte, Joaquín; Villalba, Mayte; Rodríguez, Rosalía

    2004-03-15

    Olive tree (Olea europaea) pollen is a main cause of allergy associated with extensive areas of Europe and North America. Ole e 10, a small (10.8 kDa) and acidic (pI 5.8) protein, has been identified as a major allergen from the olive pollen, isolated, and characterized. Circular dichroism analysis gave 17% alpha helix, 33% beta sheet, and 21% beta turn for its secondary structure. Based on amino acid sequences of tryptic peptides, the protein was cloned and sequenced. The allergen consists of a single polypeptide chain of 102 aa, with a signal peptide of 21 residues. Ole e 10 showed homology with the C-terminal domain of another olive allergen, Ole e 9 (1,3-beta-glucanase, 53% identity), with deduced sequences from Arabidopsis thaliana genes (42-46% identity) and with polypeptide segments (Cys boxes) of proteins involved in yeast development (Epd1/Gas-1p/Phr2 families; 42-43% similarity). Ole e 10 showed 55% prevalence for olive-allergic patients and exhibited an IgE response dependent on its conformation. Remarkable IgE cross-reactivity was detected with Ole e 9, but no correlation was observed between the individual IgE responses to both allergens. Ole e 10 shares IgE B cell epitopes with proteins from Oleaceae, Gramineae, Betulaceae, Chenopodiaceae, Cupressaceae, Ambrosia, and Parietaria pollens, latex, and vegetable foods, such as tomato, kiwi, potato, and peach. These data indicate that Ole e 10 is a new pan-allergenic plant protein that shows notable intra- and interspecie IgE cross-reactivity and is a powerful candidate to be involved in pollen-latex-fruit syndrome.

  15. Measuring angular diameter distances of strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Jee, I.; Komatsu, E.; Suyu, S. H.

    2015-11-01

    The distance-redshift relation plays a fundamental role in constraining cosmological models. In this paper, we show that measurements of positions and time delays of strongly lensed images of a background galaxy, as well as those of the velocity dispersion and mass profile of a lens galaxy, can be combined to extract the angular diameter distance of the lens galaxy. Physically, as the velocity dispersion and the time delay give a gravitational potential (GM/r) and a mass (GM) of the lens, respectively, dividing them gives a physical size (r) of the lens. Comparing the physical size with the image positions of a lensed galaxy gives the angular diameter distance to the lens. A mismatch between the exact locations at which these measurements are made can be corrected by measuring a local slope of the mass profile. We expand on the original idea put forward by Paraficz and Hjorth, who analyzed singular isothermal lenses, by allowing for an arbitrary slope of a power-law spherical mass density profile, an external convergence, and an anisotropic velocity dispersion. We find that the effect of external convergence cancels out when dividing the time delays and velocity dispersion measurements. We derive a formula for the uncertainty in the angular diameter distance in terms of the uncertainties in the observables. As an application, we use two existing strong lens systems, B1608+656 (zL=0.6304) and RXJ1131-1231 (zL=0.295), to show that the uncertainty in the inferred angular diameter distances is dominated by that in the velocity dispersion, σ2, and its anisotropy. We find that the current data on these systems should yield about 16% uncertainty in DA per object. This improves to 13% when we measure σ2 at the so-called sweet-spot radius. Achieving 7% is possible if we can determine σ2 with 5% precision.

  16. New Insights into West Antarctic Ice Sheet History Based on Ground Penetrating Radar Linking Stratigraphy With Surface-Exposure Dated Geomorphology in Lower Taylor Valley, Antarctica

    NASA Astrophysics Data System (ADS)

    Prentice, M. L.; Arcone, S.; Ackert, R.

    2002-05-01

    A most extensive record of the West Antarctic Ice Sheet (WAIS) during the last glacial cycle is found in lower Taylor Valley. We gained new insights into the drift stratigraphy using ground-penetrating radar (GPR) and surface-exposure dating in selected locations there. Evidence for the following two hypotheses will be presented. The WAIS achieved Last Glacial Maximum size between the LGM and the penultimate glaciation based on the exposure ages of boulders mantling moraines that GPR indicates are stratigraphically older than late Wisconsin drift. The drift record is on Hjorth Hill. Exposure ages range between 29 and 85 kya. The Taylor lobe of the WAIS dammed a valley-wide glacial lake, Glacial Lake Washburn between 21,200 and 8,340 14C yr BP. How and when the Taylor Lobe disintegrated are debated. We collected GPR profiles at both 100 and 400 MHz on transverse ridges that could date the recession of the Taylor Lobe. We calibrated GPR to sediment stratigraphy, primarily using 10 drill holes in eastern Taylor Valley. Ridge GPR consistently shows multiple superposed sediment packets each with internal sub-parallel reflections that resemble the stratification of migrating current ripples. We interpret the reflectors as foreset (megaripple) bedding. We think that the scalloped-shaped surfaces represent erosion indicative of a shift in current regime. Cross profiles show the festoon-shaped packets of cross-bedded units that characterize undulatory to lunate ripples. We interpret the ridges as form-discordant composite mega- and giant-current ripples. The boulders on the ripples are glacial erratics and attest to the close presence of glacial ice. The environment of deposition, ice-contact supraglacial, was characterized by high meltwater outflow from streams running off the glacier. Therefore, ridge chronology directly dates recession of the Taylor Valley lobe to about 17,000 - 13,000 14C yrs BP. Climate warming was involved in ice disintegration.

  17. Measuring angular diameter distances of strong gravitational lenses

    SciTech Connect

    Jee, I.; Komatsu, E.; Suyu, S.H. E-mail: komatsu@mpa-garching.mpg.de

    2015-11-01

    The distance-redshift relation plays a fundamental role in constraining cosmological models. In this paper, we show that measurements of positions and time delays of strongly lensed images of a background galaxy, as well as those of the velocity dispersion and mass profile of a lens galaxy, can be combined to extract the angular diameter distance of the lens galaxy. Physically, as the velocity dispersion and the time delay give a gravitational potential (GM/r) and a mass (GM) of the lens, respectively, dividing them gives a physical size (r) of the lens. Comparing the physical size with the image positions of a lensed galaxy gives the angular diameter distance to the lens. A mismatch between the exact locations at which these measurements are made can be corrected by measuring a local slope of the mass profile. We expand on the original idea put forward by Paraficz and Hjorth, who analyzed singular isothermal lenses, by allowing for an arbitrary slope of a power-law spherical mass density profile, an external convergence, and an anisotropic velocity dispersion. We find that the effect of external convergence cancels out when dividing the time delays and velocity dispersion measurements. We derive a formula for the uncertainty in the angular diameter distance in terms of the uncertainties in the observables. As an application, we use two existing strong lens systems, B1608+656 (z{sub L}=0.6304) and RXJ1131−1231 (z{sub L}=0.295), to show that the uncertainty in the inferred angular diameter distances is dominated by that in the velocity dispersion, σ{sup 2}, and its anisotropy. We find that the current data on these systems should yield about 16% uncertainty in D{sub A} per object. This improves to 13% when we measure σ{sup 2} at the so-called sweet-spot radius. Achieving 7% is possible if we can determine σ{sup 2} with 5% precision.

  18. Surface Plasmon Enhanced Phosphorescent Organic Light Emitting Diodes

    SciTech Connect

    Guillermo Bazan; Alexander Mikhailovsky

    2008-08-01

    The objective of the proposed work was to develop the fundamental understanding and practical techniques for enhancement of Phosphorescent Organic Light Emitting Diodes (PhOLEDs) performance by utilizing radiative decay control technology. Briefly, the main technical goal is the acceleration of radiative recombination rate in organometallic triplet emitters by using the interaction with surface plasmon resonances in noble metal nanostructures. Increased photonic output will enable one to eliminate constraints imposed on PhOLED efficiency by triplet-triplet annihilation, triplet-polaron annihilation, and saturation of chromophores with long radiative decay times. Surface plasmon enhanced (SPE) PhOLEDs will operate more efficiently at high injection current densities and will be less prone to degradation mechanisms. Additionally, introduction of metal nanostructures into PhOLEDs may improve their performance due to the improvement of the charge transport through organic layers via multiple possible mechanisms ('electrical bridging' effects, doping-like phenomena, etc.). SPE PhOLED technology is particularly beneficial for solution-fabricated electrophosphorescent devices. Small transition moment of triplet emitters allows achieving a significant enhancement of the emission rate while keeping undesirable quenching processes introduced by the metal nanostructures at a reasonably low level. Plasmonic structures can be introduced easily into solution-fabricated PhOLEDs by blending and spin coating techniques and can be used for enhancement of performance in existing device architectures. This constitutes a significant benefit for a large scale fabrication of PhOLEDs, e.g. by roll-to-roll fabrication techniques. Besides multieexciton annihilation, the power efficacy of PhOLEDs is often limited by high operational bias voltages required for overcoming built-in potential barriers to injection and transport of electrical charges through a device. This problem is especially

  19. Selective internalization of self-assembled artificial oil bodies by HER2/neu-positive cells

    NASA Astrophysics Data System (ADS)

    Chiang, Chung-Jen; Lin, Li-Jen; Lin, Che-Chin; Chang, Chih-Hsiang; Chao, Yun-Peng

    2011-01-01

    A novel delivery carrier was developed using artificial oil bodies (AOBs). Plant seed oil bodies (OBs) consist of a triacylglycerol matrix surrounded by a monolayer of phospholipids embedded with the storage protein oleosin (Ole). Ole consists of a central hydrophobic domain with two amphiphatic arms that extrude from the surface of OBs. In this study, a bivalent anti-HER2/neu affibody domain (ZH2) was fused with Ole at the C terminus. After overproduction in Escherichia coli, the fusion protein (Ole-ZH2) was recovered to assemble AOBs. The size of self-assembled AOBs was tailored by varying the oil/Ole-ZH2 ratio and pH to reach a nanoscale. Upon co-incubation with tumor cells, the nanoscale AOBs encapsulated with a hydrophobic fluorescence dye were selectively internalized by HER2/neu-overexpressing cells and displayed biocompatibility with the cells. In addition, the ZH2-mediated endosomal entry of AOBs occurred in a time- and AOB dose-dependent manner. The internalization efficiency was as high as 90%. The internalized AOBs disintegrated at the non-permissive pH (e.g. in acidic endosomes) and the cargo dye was released. Results of in vitro study revealed a sustained and prolonged release profile. Taken together, our findings indicate the potential of AOBs as a delivery carrier.

  20. Oleuropein Aglycone Protects Transgenic C. elegans Strains Expressing Aβ42 by Reducing Plaque Load and Motor Deficit

    PubMed Central

    Diomede, Luisa; Rigacci, Stefania; Romeo, Margherita; Stefani, Massimo; Salmona, Mario

    2013-01-01

    The presence of amyloid aggregates of the 42 amino acid peptide of amyloid beta (Aβ42) in the brain is the characteristic feature of Alzheimer’s disease (AD). Amyloid beta (Aβ deposition is also found in muscle fibers of individuals affected by inclusion body myositis (sIBM), a rare muscular degenerative disease affecting people over 50. Both conditions are presently lacking an effective therapeutic treatment. There is increasing evidence to suggest that natural polyphenols may prevent the formation of toxic amyloid aggregates; this applies also to oleuropein aglycone (OLE), the most abundant polyphenol in extra virgin olive oil, previously shown to hinder amylin and Aβ aggregation. Here we evaluated the ability of OLE to interfere with Aβ proteotoxicity in vivo by using the transgenic CL2006 and CL4176 strains of Caenorhabditis elegans, simplified models of AD and of sIBM, which express human Aβ in the cytoplasm of body wall muscle cells. OLE-fed CL2006 worms displayed reduced Aβ plaque deposition, less abundant toxic Aβ oligomers, remarkably decreased paralysis and increased lifespan with respect to untreated animals. A protective effect was also observed in CL4176 worms but only when OLE was administered before the induction of the Aβ transgene expression. These effects were specific, dose-related, and not mediated by the known polyphenolic anti-oxidant activity, suggesting that, in this model organism, OLE interferes with the Aβ aggregation skipping the appearance of toxic species, as already shown in vitro for Aβ42. PMID:23520540

  1. Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction

    SciTech Connect

    Park, Joong-Mok; Gan, Zhengqing; Leung, Wai Y.; Liu, Rui; Ye, Zhuo; Constant, Kristen; Shinar, Joseph; Shinar, Ruth; Ho, Kai-Ming

    2011-06-06

    Very uniform 2 {micro}m-pitch square microlens arrays ({micro}LAs), embossed on the blank glass side of an indium-tin-oxide (ITO)-coated 1.1 mm-thick glass, are used to enhance light extraction from organic light-emitting diodes (OLEDs) by {approx}100%, significantly higher than enhancements reported previously. The array design and size relative to the OLED pixel size appear to be responsible for this enhancement. The arrays are fabricated by very economical soft lithography imprinting of a polydimethylsiloxane (PDMS) mold (itself obtained from a Ni master stamp that is generated from holographic interference lithography of a photoresist) on a UV-curable polyurethane drop placed on the glass. Green and blue OLEDs are then fabricated on the ITO to complete the device. When the {mu}LA is {approx}15 x 15 mm{sup 2}, i.e., much larger than the {approx}3 x 3 mm{sup 2} OLED pixel, the electroluminescence (EL) in the forward direction is enhanced by {approx}100%. Similarly, a 19 x 25 mm{sup 2} {mu}LA enhances the EL extracted from a 3 x 3 array of 2 x 2 mm{sup 2} OLED pixels by 96%. Simulations that include the effects of absorption in the organic and ITO layers are in accordance with the experimental results and indicate that a thinner 0.7 mm thick glass would yield a {approx}140% enhancement.

  2. The effect of localized surface plasmon resonance on the emission color change in organic light emitting diodes.

    PubMed

    Lee, Illhwan; Park, Jae Yong; Hong, Kihyon; Son, Jun Ho; Kim, Sungjun; Lee, Jong-Lam

    2016-03-28

    Three primary colors, cyan, yellow, and green, are obtained from Ag nano-dot embedded organic light emitting diodes (OLEDs) by localized surface plasmon resonance (LSPR). By changing the thickness of the Ag film, the size and spacing of Ag nano-dots are controlled. The generated light from the emissive layer in the OLEDs interacts with the free electrons near the surface of the Ag nano-dots, which leads to LSPR absorption and scattering. The UV-visible absorption spectra of glass/ITO/Ag nano-dot samples show intense peaks from 430 nm to 520 nm with an increase of Ag nano-dot size. And also, the Rayleigh scattering spectra results show the plasmon resonance wavelength in the range of 470-550 nm. The effect of the LSPR of Ag nano-dots on the change of emission color in OLEDs is demonstrated using 2 dimensional finite-difference time-domain simulations. The intensity of the electro-magnetic field in the sample with 5 nm-thick Ag is low at the incident wavelength of 500 nm, but it increases with the incident wavelength. This provides evidence that the emission color change in OLEDs originates from LSPR at the Ag nano-dots. As a result, the emission peak wavelength of OLEDs shifted toward longer wavelengths, from cyan to yellow-green, with the increase of Ag nano-dot size.

  3. Evaluation and prediction of color-tunable organic light-emitting diodes based on carrier/exciton adjusting interlayer

    NASA Astrophysics Data System (ADS)

    Liu, Shengqiang; Li, Jie; Du, Chunlei; Yu, Junsheng

    2015-07-01

    A color tuning index (ICT) parameter for evaluating the color change capability of color-tunable organic light-emitting diodes (CT-OLEDs) was proposed and formulated. And a series of CT-OLEDs, consisting of five different carrier/exciton adjusting interlayers (C/EALs) inserted between two complementary emitting layers, were fabricated and applied to disclose the relationship between ICT and C/EALs. The result showed that the trend of electroluminescence spectra behavior in CT-OLEDs has good accordance with ICT values, indicating that the ICT parameter is feasible for the evaluation of color variation. Meanwhile, by changing energy level and C/EAL thickness, the optimized device with the widest color tuning range was based on N,N'-dicarbazolyl-3,5-benzene C/EAL, exhibiting the highest ICT value of 41.2%. Based on carrier quadratic hopping theory and exciton transfer model, two fitting ICT formulas derived from the highest occupied molecular orbital (HOMO) energy level and triplet energy level were simulated. Finally, a color tuning prediction (CTP) model was developed to deduce the ICT via C/EAL HOMO and triplet energy levels, and verified by the fabricated OLEDs with five different C/EALs. We believe that the CTP model assisted with ICT parameter will be helpful for fabricating high performance CT-OLEDs with a broad range of color tuning.

  4. Magnetically modulated electroluminescence from hybrid organic/inorganic light-emitting diodes based on electron donor-acceptor exciplex blends

    NASA Astrophysics Data System (ADS)

    Pang, Zhiyong; Baniya, Sangita; Zhang, Chuang; Sun, Dali; Vardeny, Z. Valy

    2016-03-01

    We report room temperature magnetically modulated electroluminescence from a hybrid organic/inorganic light-emitting diode (h-OLED), in which an inorganic magnetic tunnel junction (MTJ) with large room temperature magnetoresistance is coupled to an N,N,N ',N '-Tetrakis(4-methoxyphenyl)benzidine (MeO-TPD): tris-[3-(3-pyridyl)mesityl]borane (3TPYMB) [D-A] based OLED that shows thermally activated delayed luminescence. The exciplex-based OLED provides two spin-mixing channels: upper energy channel of polaron pairs and lower energy channel of exciplexes. In operation, the large resistance mismatch between the MTJ and OLED components is suppressed due to the non-linear I-V characteristic of the OLED. This leads to enhanced giant magneto-electroluminescence (MEL) at room temperature. We measured MEL of ~ 75% at ambient conditions. Supported by SAMSUNG Global Research Outreach (GRO) program, and also by the NSF-Material Science & Engineering Center (MRSEC) program at the University of Utah (DMR-1121252).

  5. Potential effect of Olea europea leaves, Sonchus oleraceus leaves and Mangifera indica peel extracts on aromatase activity in human placental microsomes and CYP19A1 expression in MCF-7 cell line: Comparative study.

    PubMed

    Shaban, N Z; Hegazy, W A; Abdel-Rahman, S M; Awed, O M; Khalil, S A

    2016-08-29

    Aromatase inhibitors (AIs) provide novel approaches to the adjuvant therapy for postmenopausal women with estrogen-receptor-positive (ER+) breast cancers. In this study, different plant extracts from Olea europaea leaves (OLE), Sonchus oleraceus L. (SOE) and Mangifera indica peels (MPE) were prepared to identify phytoconstituents and measure antioxidant capacities. The effects of these three extracts on aromatase activity in human placental microsomes were evaluated. Additionally, the effects of these extracts on tissue-specific promoter expression of CYP19A1 gene in cell culture model (MCF-7) were assessed using qRT-PCR. Results showed a concentration-dependent decrease in aromatase activity after treatment with OLE and MPE, whereas, SOE showed a biphasic effect. The differential effects of OLE, SOE and MPE on aromatase expression showed that OLE seems to be the most potent suppressor followed by SOE and then MPE. These findings indicate that OLE has effective inhibitory action on aromatase at both the enzymatic and expression levels, in addition to its cytotoxic effect against MCF-7 cells. Also, MPE may be has the potential to be used as a tissue-specific aromatase inhibitor (selective aromatase inhibitor) and it may be promising to develop a new therapeutic agent against ER+ breast cancer.

  6. Olive Leaf Extract Attenuates Obesity in High-Fat Diet-Fed Mice by Modulating the Expression of Molecules Involved in Adipogenesis and Thermogenesis

    PubMed Central

    Song, Su Jin

    2014-01-01

    The present study aimed to investigate whether olive leaf extract (OLE) prevents high-fat diet (HFD)-induced obesity in mice and to explore the underlying mechanisms. Mice were randomly divided into groups that received a chow diet (CD), HFD, or 0.15% OLE-supplemented diet (OLD) for 8 weeks. OLD-fed mice showed significantly reduced body weight gain, visceral fat-pad weights, and plasma lipid levels as compared with HFD-fed mice. OLE significantly reversed the HFD-induced upregulation of WNT10b- and galanin-mediated signaling molecules and key adipogenic genes (PPARγ, C/EBPα, CD36, FAS, and leptin) in the epididymal adipose tissue of HFD-fed mice. Furthermore, the HFD-induced downregulation of thermogenic genes involved in uncoupled respiration (SIRT1, PGC1α, and UCP1) and mitochondrial biogenesis (TFAM, NRF-1, and COX2) was also significantly reversed by OLE. These results suggest that OLE exerts beneficial effects against obesity by regulating the expression of genes involved in adipogenesis and thermogenesis in the visceral adipose tissue of HFD-fed mice. PMID:24624222

  7. Olive Oil Polyphenols Differentially Inhibit Smooth Muscle Cell Proliferation through a G1/S Cell Cycle Block Regulated by ERK1/2

    PubMed Central

    Abe, Rei; Beckett, Joel; Abe, Ryuzo; Nixon, Alexander; Rochier, Adrienne; Yamashita, Norio; Sumpio, Bauer

    2012-01-01

    We hypothesized that polyphenols contained in olive oil play a role in reducing the risk of atherosclerosis. The aim of this study was to determine if the polyphenols in olive oil, oleuropein (Ole), hydroxytyrosol (HT), and tyrosol (Tyr) could inhibit smooth muscle cell (SMC) proliferation through its influence on cell cycle regulation. Bovine vascular SMC were cultured in the presence of Ole, HT, or Tyr at concentration of 1, 10, or 100 μmol/L. On days 1, 3, and 5, numbers of cells were counted. Cell cycle analysis was performed by flow cytometry on day 1 after SMC were stained with propidium iodide. Cell populations grown in the presence of Ole or HT at 100 μmol/L concentration were significantly inhibited after 5 days of exposure. Tyr had a similar tendency but it did not attain significance. Cell cycle analysis revealed that 66% of cells were in G1 phase in Ole group, compared with 48% in control group. To examine the cell cycle block between G1 and S phases, we performed Western blotting and found that ERK1/2 activation was inhibited by Ole or HT. We conclude that olive oil polyphenols could inhibit SMC proliferation through a cell cycle block between G1 and S phases which may be regulated by ERK1/2. These results demonstrate a mechanism by which olive oil consumption may be atheroprotective by inhibiting SMC proliferation. PMID:23730132

  8. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

    PubMed Central

    Achour, Imène; Arel-Dubeau, Anne-Marie; Renaud, Justine; Legrand, Manon; Attard, Everaldo; Germain, Marc; Martinoli, Maria-Grazia

    2016-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model. PMID:27517912

  9. Direct monitoring of bias-dependent variations in the exciton formation ratio of working organic light emitting diodes

    PubMed Central

    Takahashi, Takahiro; Kanemoto, Katsuichi; Kanenobu, Mariko; Okawauchi, Yuta; Hashimoto, Hideki

    2015-01-01

    In typical operation of organic light emitting diodes (OLEDs), excitons are assumed to generate with a ratio of 1:3 for singlet and triplet excitons, respectively, based on a simple spin statistics model. This assumption has been used in designing efficient OLEDs. Despite the larger generation ratio of triplet excitons, physical properties of fluorescent OLEDs are usually evaluated only through the electroluminescence (EL) intensity from singlets and the behaviors of triplets during the LED operation are virtually black-boxed, because the triplets are mostly non-emissive. Here, we employ transient spectroscopy combined with LED-operation for directly monitoring the non-emissive triplets of working OLEDs. The spectroscopic techniques are performed simultaneously with EL- and current measurements under various operation biases. The simultaneous measurements reveal that the relative formation ratio of singlet-to-triplet excitons dramatically changes with the magnitude of bias. The measurements also show that the generation efficiency of singlets scales with the bias, whereas that of triplets is nearly bias-independent. These features of the formation ratio and efficiency are compatibly explained by considering the yield of intersystem crossing and the energy separation of excitons from electron-hole pairs. The obtained findings via the spectroscopic measurements enable prediction of the formation pathways in OLEDs. PMID:26487499

  10. Carbon Nanotube Driver Circuit for 6 × 6 Organic Light Emitting Diode Display

    PubMed Central

    Zou, Jianping; Zhang, Kang; Li, Jingqi; Zhao, Yongbiao; Wang, Yilei; Pillai, Suresh Kumar Raman; Volkan Demir, Hilmi; Sun, Xiaowei; Chan-Park, Mary B.; Zhang, Qing

    2015-01-01

    Single-walled carbon nanotube (SWNT) is expected to be a very promising material for flexible and transparent driver circuits for active matrix organic light emitting diode (AM OLED) displays due to its high field-effect mobility, excellent current carrying capacity, optical transparency and mechanical flexibility. Although there have been several publications about SWNT driver circuits, none of them have shown static and dynamic images with the AM OLED displays. Here we report on the first successful chemical vapor deposition (CVD)-grown SWNT network thin film transistor (TFT) driver circuits for static and dynamic AM OLED displays with 6 × 6 pixels. The high device mobility of ~45 cm2V−1s−1 and the high channel current on/off ratio of ~105 of the SWNT-TFTs fully guarantee the control capability to the OLED pixels. Our results suggest that SWNT-TFTs are promising backplane building blocks for future OLED displays. PMID:26119218

  11. Degradation of Hole Transport Materials via Exciton-Driven Cyclization.

    PubMed

    Bell, Bruce M; Clark, Michael B; Devore, David D; De Vries, Timothy S; Froese, Robert D; Gray, Kaitlyn C; Jackson, David H K; Kuech, T F; Na, Hong-Yeop; Kearns, Kenneth L; Lee, Kyung-Joo; Mukhopadhyay, Sukrit; Rachford, Aaron A; Spencer, Liam P; Woodward, W H Hunter

    2017-04-06

    Organic light-emitting diode (OLED) displays have been an active and intense area of research for well over a decade and have now reached commercial success for displays from cell phones to large format televisions. A more thorough understanding of the many different potential degradation modes which cause OLED device failure will be necessary to develop the next generation of OLED materials, improve device lifetime, and to ultimately improve the cost vs performance ratio. Each of the different organic layers in an OLED device can be susceptible to unique decomposition pathways, however stability toward excitons is critical for emissive layer (EML) materials as well as any layer near the recombination zone. This study will specifically focus on degradation modes within the hole transport layer (HTL) with the goal being to identify the general decomposition paths occurring in an operating device and use this information to design new derivatives which can block these pathways. Through post-mortem analyses of several aged OLED devices, an apparently common intramolecular cyclization pathway has been identified that was not previously reported for arylamine-containing HTL materials and that operates parallel to but faster than the previously described fragmentation pathways.

  12. Oleuropein aglycone protects transgenic C. elegans strains expressing Aβ42 by reducing plaque load and motor deficit.

    PubMed

    Diomede, Luisa; Rigacci, Stefania; Romeo, Margherita; Stefani, Massimo; Salmona, Mario

    2013-01-01

    The presence of amyloid aggregates of the 42 amino acid peptide of amyloid beta (Aβ42) in the brain is the characteristic feature of Alzheimer's disease (AD). Amyloid beta (Aβ deposition is also found in muscle fibers of individuals affected by inclusion body myositis (sIBM), a rare muscular degenerative disease affecting people over 50. Both conditions are presently lacking an effective therapeutic treatment. There is increasing evidence to suggest that natural polyphenols may prevent the formation of toxic amyloid aggregates; this applies also to oleuropein aglycone (OLE), the most abundant polyphenol in extra virgin olive oil, previously shown to hinder amylin and Aβ aggregation. Here we evaluated the ability of OLE to interfere with Aβ proteotoxicity in vivo by using the transgenic CL2006 and CL4176 strains of Caenorhabditis elegans, simplified models of AD and of sIBM, which express human Aβ in the cytoplasm of body wall muscle cells. OLE-fed CL2006 worms displayed reduced Aβ plaque deposition, less abundant toxic Aβ oligomers, remarkably decreased paralysis and increased lifespan with respect to untreated animals. A protective effect was also observed in CL4176 worms but only when OLE was administered before the induction of the Aβ transgene expression. These effects were specific, dose-related, and not mediated by the known polyphenolic anti-oxidant activity, suggesting that, in this model organism, OLE interferes with the Aβ aggregation skipping the appearance of toxic species, as already shown in vitro for Aβ42.

  13. Ultrahigh-efficiency solution-processed simplified small-molecule organic light-emitting diodes using universal host materials

    PubMed Central

    Han, Tae-Hee; Choi, Mi-Ri; Jeon, Chan-Woo; Kim, Yun-Hi; Kwon, Soon-Ki; Lee, Tae-Woo

    2016-01-01

    Although solution processing of small-molecule organic light-emitting diodes (OLEDs) has been considered as a promising alternative to standard vacuum deposition requiring high material and processing cost, the devices have suffered from low luminous efficiency and difficulty of multilayer solution processing. Therefore, high efficiency should be achieved in simple-structured small-molecule OLEDs fabricated using a solution process. We report very efficient solution-processed simple-structured small-molecule OLEDs that use novel universal electron-transporting host materials based on tetraphenylsilane with pyridine moieties. These materials have wide band gaps, high triplet energy levels, and good solution processabilities; they provide balanced charge transport in a mixed-host emitting layer. Orange-red (~97.5 cd/A, ~35.5% photons per electron), green (~101.5 cd/A, ~29.0% photons per electron), and white (~74.2 cd/A, ~28.5% photons per electron) phosphorescent OLEDs exhibited the highest recorded electroluminescent efficiencies of solution-processed OLEDs reported to date. We also demonstrate a solution-processed flexible solid-state lighting device as a potential application of our devices. PMID:27819053

  14. Influence of PEDOT:PSS on the effectiveness of barrier layers prepared by atomic layer deposition in organic light emitting diodes

    SciTech Connect

    Wegler, Barbara; Schmidt, Oliver; Hensel, Bernhard

    2015-01-15

    Organic light emitting diodes (OLEDs) are well suited for energy saving lighting applications, especially when thinking about highly flexible and large area devices. In order to avoid the degradation of the organic components by water and oxygen, OLEDs need to be encapsulated, e.g., by a thin sheet of glass. As the device is then no longer flexible, alternative coatings are required. Atomic layer deposition (ALD) is a very promising approach in this respect. The authors studied OLEDs that were encapsulated by 100 nm Al{sub 2}O{sub 3} deposited by ALD. The authors show that this coating effectively protects the active surface area of the OLEDs from humidity. However, secondary degradation processes still occur at sharp edges of the OLED stack where the extremely thin encapsulation layer does not provide perfect coverage. Particularly, the swelling of poly(3,4-ethylenedioxythiophene) mixed with poly(styrenesulfonate), which is a popular choice for the planarization of the bottom electrode and at the same time acts as a hole injection layer, affects the effectiveness of the encapsulation layer.

  15. Inverted organic light-emitting diodes using different transparent conductive oxide films as a cathode

    NASA Astrophysics Data System (ADS)

    Takada, Makoto; Kobayashi, Takashi; Nagase, Takashi; Naito, Hiroyoshi

    2016-03-01

    We report on poly(dioctylfluorene-alt-benzothiadiazole) (F8BT) based inverted organic light-emitting diodes (iOLEDs) using commercially available transparent conductive oxide (TCO) films as a cathode, indium tin oxide (ITO), Ga doped ZnO (GZO), and Al doped ZnO (AZO). The ITO, GZO, and AZO glasses work as an electron-injecting layer (EIL) and cathode. The device configuration that we prepared is ITO, GZO, or AZO/F8BT/MoO3/Au. The device characteristics of these iOLEDs are almost comparable to those of conventional iOLEDs with ZnO films prepared by spray pyrolysis as an EIL, indicating that the electron injection properties of ITO, GZO, or AZO as a cathode are similar to those of ZnO layer in conventional iOLEDs. These results demonstrate the low-cost fabrication of iOLEDs utilizing commercially available TCO glasses as a cathode without deposition of ZnO layers on ITO glass.

  16. Up to 100% Formation Ratio of Doublet Exciton in Deep-Red Organic Light-Emitting Diodes Based on Neutral π-Radical.

    PubMed

    Obolda, Ablikim; Ai, Xin; Zhang, Ming; Li, Feng

    2016-12-28

    In a neutral π-radical-based organic light-emitting diode (OLED), although the emission comes from the doublet excitons and their transition to the ground state is spin-allowed, the upper limit of internal quantum efficiency (IQE) is not clear, 50% or 100%? In this work, the deep-red OLEDs based on a neutral π-radical were fabricated. Up to 100% doublet exciton formation ratio was obtained through rational designing device structure and host-guest doping system. This indicates the IQE of neutral π-radical-based OLEDs will reach 100% if the nonradiative pathways of radicals can be suppressed. The maximum external quantum efficiency of the optimized device is as high as 4.3%, which is among the highest values of deep-red/near-infrared OLEDs with nonphosphorescent materials as emitters. Our results also indicate that using partially reduced radical mixture as emitter may be a way to solve aggregation-caused quenching in radical-based OLEDs.

  17. Active matrix organic light-emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Ghosh, Amalkumar; Prache, Olivier; Wacyk, Ihor; Ali, Tariq; Khayrullin, Ilyas

    2011-06-01

    The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through research and development programs from 2007 to 2010 with the US Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 triad pixels) OLED microdisplay. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2007, 2008, 2009, and 2010 SPIE Defense and Security Symposia1,2,3,4. Life and performance tests have continued through 2010, and this data will be presented 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 desirable.

  18. Active matrix organic light emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Botkin, Michael E.; Draper, Russell S.; Coletta, Jason

    2013-05-01

    The U.S. Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through Research and Development programs from 2007 to 2012 with the U.S. Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 with triad pixels) and WUXGA (1920 X 1200 with triad pixels) OLED microdisplays. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2012, 2011, 2010, 2009, 2008, and 2007 SPIE Defense, Security and Sensing Symposia. Life and performance tests have continued through 2013, and this data will be presented along with a comparison to 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 desirable.

  19. The relationship between basic audio quality and overall listening experience.

    PubMed

    Schoeffler, Michael; Herre, Jürgen

    2016-09-01

    Basic audio quality (BAQ) is a well-known perceptual attribute, which is rated in various listening test methods to measure the performance of audio systems. Unfortunately, when it comes to purchasing audio systems, BAQ might not have a significant influence on the customers' buying decisions since other factors, like brand loyalty, might be more important. In contrast to BAQ, overall listening experience (OLE) is an affective attribute which incorporates all aspects that are important to an individual assessor, including his or her preference for music genre and audio quality. In this work, the relationship between BAQ and OLE is investigated in more detail. To this end, an experiment was carried out, in which participants rated the BAQ and the OLE of music excerpts with different timbral and spatial degradations. In a between-group-design procedure, participants were assigned into two groups, in each of which a different set of stimuli was rated. The results indicate that rating of both attributes, BAQ and OLE, leads to similar rankings, even if a different set of stimuli is rated. In contrast to the BAQ ratings, which were more influenced by timbral than spatial degradations, the OLE ratings were almost equally influenced by timbral and spatial degradations.

  20. Suppression of external quantum efficiency roll-off of nanopatterned organic-light emitting diodes at high current densities

    SciTech Connect

    Kuwae, Hiroyuki; Kasahara, Takashi; Nitta, Atsushi; Yoshida, Kou; Inoue, Munetomo; Matsushima, Toshinori; Adachi, Chihaya; Shoji, Shuichi; Mizuno, Jun

    2015-10-21

    We developed organic light-emitting diodes (OLEDs) with nanopatterned current flow regions using electron-beam lithography with the aim of suppressing singlet–polaron annihilation (SPA). Nanopatterns composed of lines and circles were used in the current flow regions of nano-line and nano-dot OLEDs, respectively. Excitons partially escape from the current flow regions where SPA takes place. As such, current densities where external quantum efficiencies were half of their initial values (J{sub 0}) increased as line width and circle diameter were decreased to close to the exciton diffusion length. Circles were more efficient at enhancing exciton escape and increasing J{sub 0} than lines. The J{sub 0} increase in the nano-dot OLEDs containing nanopatterned circles with a diameter of 50 nm was approximately 41-fold that of a conventional OLED with a current flow region of 4 mm{sup 2}. The dependence of J{sub 0} on the size and shape of the nanopatterns was well explained by an SPA model that considered exciton diffusion. Nanopatterning of OLEDs is a feasible method of obtaining large J{sub 0}.

  1. Improvement of device performance of polymer organic light-emitting diodes on smooth transparent sheet with graphene films synthesized by plasma treatment

    NASA Astrophysics Data System (ADS)

    Okigawa, Yuki; Mizutani, Wataru; Suzuki, Kenkichi; Ishihara, Masatou; Yamada, Takatoshi; Hasegawa, Masataka

    2015-09-01

    Because graphene films have one-atom thickness, the morphology of the transparent sheets could have a greater effect on the performance of organic light-emitting diode (OLED) devices with graphene films than on that with indium tin oxide (ITO). In this study, we have evaluated the polymer OLED devices with graphene films synthesized by plasma treatment on poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) sheets having high flatness. The results imply that the surface roughness of the transparent sheets predominantly affects the luminescence of polymer OLED devices with graphene films. The suppression of leakage current and a luminescence higher than 8000 cd/m2 at 15 V were attained for the devices on the transparent sheet with higher flatness in spite of the presence of large sharp spikes.

  2. Fabrication of Vertical Organic Light-Emitting Transistor Using ZnO Thin Film

    NASA Astrophysics Data System (ADS)

    Yamauchi, Hiroshi; Iizuka, Masaaki; Kudo, Kazuhiro

    2007-04-01

    Organic light-emitting diodes (OLEDs) combined with thin film transistor (TFT) are well suitable elements for low-cost, large-area active matrix displays. On the other hand, zinc oxide (ZnO) is a transparent material and its electrical conductivity is controlled from conductive to insulating by growth conditions. The drain current of ZnO FET is 180 μA. The OLED uses ZnO thin film (Al-doped) for the electron injection layer and is controlled by radio frequency (rf) and direct current (dc) sputtering conditions, such as Al concentration and gas pressure. Al concentration in the ZnO film and deposition rate have strong effects on electron injection. Furthermore, the OLED driven by ZnO FET shows a luminance of 13 cd/m2, a luminance efficiency of 0.7 cd/A, and an on-off ratio of 650.

  3. Teaching in the Field: What Teacher Professional Life Histories Tell About How They Learn to Teach in the Outdoor Learning Environment

    NASA Astrophysics Data System (ADS)

    Feille, Kelly K.

    2016-06-01

    This research investigates the professional life histories of upper elementary science teachers who were identified as effective both within the classroom and in the outdoor learning environment (OLE). The narratives of five teachers, collected through semistructured and open-ended interviews, provided the data for the study. Professional life histories were constructed for each teacher participant and an analysis of the teacher narratives identified the themes of teacher development across the voices of the participants. Narrative reasoning was used to unify those themes into a hypothetical professional life history as reported in this manuscript. Implications of this research can be realized for stakeholders in the preparation of pre-service teachers as well as the development of in-service teachers. Future research regarding the early induction years of new teachers, impacts of inclusion of the OLE in pre-service teacher instruction, and teacher experiences regarding professional development relating to efforts to include the OLE in formal education should be investigated.

  4. White organic light-emitting diodes with 4 nm metal electrode

    SciTech Connect

    Lenk, Simone; Schwab, Tobias; Schubert, Sylvio; Müller-Meskamp, Lars; Leo, Karl; Reineke, Sebastian; Gather, Malte C.

    2015-10-19

    We investigate metal layers with a thickness of only a few nanometers as anode replacement for indium tin oxide (ITO) in white organic light-emitting diodes (OLEDs). The ultrathin metal electrodes prove to be an excellent alternative that can, with regard to the angular dependence and efficiency of the OLED devices, outperform the ITO reference. Furthermore, unlike ITO, the thin composite metal electrodes are readily compatible with demanding architectures (e.g., top-emission or transparent OLEDs, device unit stacking, etc.) and flexible substrates. Here, we compare the sheet resistance of both types of electrodes on polyethylene terephthalate for different bending radii. The electrical performance of ITO breaks down at a radius of 10 mm, while the metal electrode remains intact even at radii smaller than 1 mm.

  5. Effects of emission layer doping on the spatial distribution of charge and host recombination rate density in organic light emitting devices: A numerical study

    SciTech Connect

    Li, Yanli; Zhou, Maoqing; Zheng, Tingcai; Yao, Bo; Peng, Yingquan

    2013-12-28

    Based on drift-diffusion theory, a numerical model of the doping of a single energy level trap in the emission layer of an organic light emitting device (OLED) was developed, and the effects of doping of this single energy level trap on the distribution of the charge density, the recombination rate density, and the electric field in single- and double-layer OLEDs were studied numerically. The results show that by doping the n-type (p-type) emission layer with single energy electron (hole) traps, the distribution of the recombination rate density can be tuned and shifted, which is useful for improvement of the device performance by reduced electrode quenching or for realization of desirable special functions, e.g., emission spectrum tuning in multiple dye-doped white OLEDs.

  6. Simulation of mixed-host emitting layer based organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Riku, C.; Kee, Y. Y.; Ong, T. S.; Yap, S. S.; Tou, T. Y.

    2015-04-01

    `SimOLED' simulator is used in this work to investigate the efficiency of the mixed-host organic light emitting devices (MH-OLEDs). Tris-(8-hydroxyquinoline) aluminum(3) (Alq3) and N,N-diphenyl-N,N-Bis(3-methylphenyl)-1,1-diphenyl-4,4-diamine (TPD) are used as the electron transport layer (ETL) material and hole transport layer (HTL) material respectively, and the indium-doped tin oxide (ITO) and aluminum (Al) as anode and cathode. Three MH-OLEDs, A, B and C with the same structure of ITO / HTM (15 nm) / Mixed host (70 nm) / ETM (10 nm) /Al, are stimulated with ratios TPD:Alq3 of 3:5, 5:5, and 5:3 respectively. The Poole-Frenkel model for electron and hole mobilities is employed to compute the current density-applied voltage-luminance characteristics, distribution of the electric field, carrier concentrations and recombination rate.

  7. Improved electron injection and transport by use of baking soda as a low-cost, air-stable, n-dopant for solution-processed phosphorescent organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Earmme, Taeshik; Jenekhe, Samson A.

    2013-06-01

    Sodium bicarbonate (baking soda, NaHCO3) is found to be an efficient low-cost, air-stable, and environmentally friendly n-dopant for electron-transport layer (ETL) in solution-processed phosphorescent organic light-emitting diodes (PhOLEDs). A 2.0-fold enhancement in power efficiency of blue PhOLEDs is observed by use of NaHCO3-doped 4,7-diphenyl-1,10-phenanthroline (BPhen) ETL. The bulk conductivity of NaHCO3-doped BPhen film is increased by 5 orders of magnitude. Enhanced performance of PhOLEDs is similarly observed by use of NaHCO3-doped 1,3,5-tris(m-pyrid-3-yl-phenyl)benzene ETL. These results demonstrate that sodium bicarbonate is an effective n-dopant in organic electronics.

  8. Novel non-conjugated main-chain hole-transporting polymers for organic electronics application.

    PubMed

    Schelter, Jürgen; Mielke, Georg Felix; Köhnen, Anne; Wies, Jenna; Köber, Sebastian; Nuyken, Oskar; Meerholz, Klaus

    2010-09-01

    A new class of hole-transporting polymers for use in organic electronic devices such as organic light-emitting diodes (OLEDs) or photorefractive holographic storage devices has been synthesized. The polymers contain tetraarylbenzidines or tetraarylphenylenediamines as charge-transporting units in the polymer backbone and are connected by non-conjugating fluorene bridges. For use in OLEDs the novel polymers were functionalized with oxetane groups that can be cross-linked via a cationic ring opening polymerization to yield insoluble networks. Such insoluble films are necessary for the fabrication of multilayer devices by wet deposition techniques. The novel materials feature improved film-formation properties as demonstrated in green-emitting double-layer OLEDs.

  9. Enhanced out-coupling efficiency of organic light-emitting diodes using an nanostructure imprinted by an alumina nanohole array

    SciTech Connect

    Endo, Kuniaki; Adachi, Chihaya

    2014-03-24

    We demonstrate organic light-emitting diodes (OLEDs) with enhanced out-coupling efficiency containing nanostructures imprinted by an alumina nanohole array template that can be applied to large-emitting-area and flexible devices using a roll-to-roll process. The nanostructures are imprinted on a glass substrate by an ultraviolet nanoimprint process using an alumina nanohole array mold and then an OLED is fabricated on the nanostructures. The enhancement of out-coupling efficiency is proportional to the root-mean-square roughness of the nanostructures, and a maximum improvement of external electroluminescence quantum efficiency of 17% is achieved. The electroluminescence spectra of the OLEDs indicate that this improvement is caused by enhancement of the out-coupling of surface plasmon polaritons.

  10. Highly efficient electroluminescence from a solution-processable thermally activated delayed fluorescence emitter

    SciTech Connect

    Wada, Yoshimasa; Kubo, Shosei; Suzuki, Katsuaki; Kaji, Hironori; Shizu, Katsuyuki; Tanaka, Hiroyuki; Adachi, Chihaya

    2015-11-02

    We developed a thermally activated delayed fluorescence (TADF) emitter, 2,4,6-tris(4-(9,9-dimethylacridan-10-yl)phenyl)-1,3,5-triazine (3ACR-TRZ), suitable for use in solution-processed organic light-emitting diodes (OLEDs). When doped into 4,4′-bis(carbazol-9-yl)biphenyl (CBP) host at 16 wt. %, 3ACR-TRZ showed a high photoluminescence quantum yield of 98%. Transient photoluminescence decay measurements of the 16 wt. % 3ACR-TRZ:CBP film confirmed that 3ACR-TRZ exhibits efficient TADF with a triplet-to-light conversion efficiency of 96%. This high conversion efficiency makes 3ACR-TRZ attractive as an emitting dopant in OLEDs. Using 3ACR-TRZ as an emitter, we fabricated a solution-processed OLED exhibiting a maximum external quantum efficiency of 18.6%.

  11. Simultaneous monitoring of singlet and triplet exciton variations in solid organic semiconductors driven by an external static magnetic field

    SciTech Connect

    Ding, Baofu Alameh, Kamal

    2014-07-07

    The research field of organic spintronics has remarkably and rapidly become a promising research area for delivering a range of high-performance devices, such as magnetic-field sensors, spin valves, and magnetically modulated organic light emitting devices (OLEDs). Plenty of microscopic physical and chemical models based on exciton or charge interactions have been proposed to explain organic magneto-optoelectronic phenomena. However, the simultaneous observation of singlet- and triplet-exciton variations in an external magnetic field is still unfeasible, preventing a thorough theoretical description of the spin dynamics in organic semiconductors. Here, we show that we can simultaneously observe variations of singlet excitons and triplet excitons in an external magnetic field, by designing an OLED structure employing a singlet-exciton filtering and detection layer in conjunction with a separate triplet-exciton detection layer. This OLED structure enables the observation of a Lorentzian and a non-Lorentzian line-shape magnetoresponse for singlet excitons and triplet excitons, respectively.

  12. Heteroleptic cyclometalated Ir(III) complexes with charge transporting groups: A theoretical study

    SciTech Connect

    Padmaperuma, Asanga B.; Fernandez, Carlos A.

    2012-09-13

    Efficient and stable high energy organic light emitting devices (OLEDs) are a vital component of new generation general illumination solutions. However, large charge imbalances in the emissive layer of OLEDs lead to charge accumulation and subsequent side reactions which lowers the device efficiency and dramatically shortens operational lifetime. Radical changes in the way emitter materials are designed are needed to address this problem. Conventional approaches have only focused on color tuning; however, multi-functional emitter materials are needed to assist the transport of charge in the emissive layer. We propose to design and synthesize new organometallic iridium phosphorescent materials with bipolar charge transport properties to be used in high energy OLEDs and white light configurations

  13. Film Properties and Polycrystallization of Organic Dyes on ITOs with Surface Treatment for Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Iwama, Yuki; Mori, Tatsuo; Mizutani, Teruyoshi

    ITO(Indium-Tin-Oxide) has been now widely used as the transparent anode for organic light-emitting devices(OLEDs). We used various methods of ITO surface treatment and examined the effects of them by measuring contact angle and calculating surface energy. We also prepared OLEDs with ITO treated by each method, and estimated their characteristics. The surface of ITO treated by UV-O3 or O2-plasma was more hydrophilic than that treated by only organic rinse or no treatment, and consequently the characteristic of the OLED was improved. We suppose these treatments affect the hole injection from ITO into organic layer, due to ionization potential or surface cleanness. We also investigated time degradation of NPD films on the ITO substrates. The films deposited with high deposition rate porycrystallized faster.

  14. Characteristics of blue organic light emitting diodes with different thick emitting layers

    NASA Astrophysics Data System (ADS)

    Li, Chong; Tsuboi, Taiju; Huang, Wei

    2014-08-01

    We fabricated blue organic light emitting diodes (called blue OLEDs) with emitting layer (EML) of diphenylanthracene derivative 9,10-di(2-naphthyl)anthracene (ADN) doped with blue-emitting DSA-ph (1-4-di-[4-(N,N-di-phenyl)amino]styryl-benzene) to investigate how the thickness of EML and hole injection layer (HIL) influences the electroluminescence characteristics. The driving voltage was observed to increase with increasing EML thickness from 15 nm to 70 nm. The maximum external quantum efficiency of 6.2% and the maximum current efficiency of 14 cd/A were obtained from the OLED with 35 nm thick EML and 75 nm thick HIL. High luminance of 120,000 cd/m2 was obtained at 7.5 V from OLED with 15 nm thick EML.

  15. Improvement of light extraction efficiency and reduction of driving voltage in organic light emitting diodes using a plasmonic crystal

    SciTech Connect

    Okamoto, Takayuki; Shinotsuka, Kei

    2014-03-03

    Two-dimensional periodic corrugation was introduced into the surface of metallic cathodes of organic light-emitting diodes (OLEDs) to extract surface plasmon energy, which is trapped in that surface, as free-space photons. The dependence of the improvement factor of the emission efficiency on the modulation depth of the corrugation was systematically investigated. The corrugation was fabricated by using a colloidal lithography technique, which can be easily applied to a wide area. The obtained maximum improvement factor in current efficiency was 1.67 for an OLED with a 40 nm modulation depth, whereas the improvement in power efficiency was 2.35 for an OLED with a 60 nm modulation depth. We attributed the former improvement factor purely to optical effects and the latter to both optical and electrical effects, namely, a reduction of the electrical resistance of the organic layers due to the introduced corrugation.

  16. All-solution processed transparent organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Höfle, Stefan; Czolk, Jens; Mertens, Adrian; Colsmann, Alexander

    2015-11-01

    In this work, we report on indium tin oxide-free, all-solution processed transparent organic light emitting diodes (OLEDs) with inverted device architecture. Conductive polymer layers are employed as both transparent cathodes and transparent anodes, with the top anodes having enhanced conductivities from a supporting stochastic silver nanowire mesh. Both electrodes exhibit transmittances of 80-90% in the visible spectral regime. Upon the incorporation of either yellow- or blue-light emitting fluorescent polymers, the OLEDs show low onset voltages, demonstrating excellent charge carrier injection from the polymer electrodes into the emission layers. Overall luminances and current efficiencies equal the performance of opaque reference OLEDs with indium tin oxide and aluminium electrodes, proving excellent charge carrier-to-light conversion within the device.

  17. Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures

    PubMed Central

    Wei, Mao-Kuo; Lin, Chii-Wann; Yang, Chih-Chung; Kiang, Yean-Woei; Lee, Jiun-Haw; Lin, Hoang-Yan

    2010-01-01

    In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs) and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode. PMID:20480033

  18. Operating organic light-emitting diodes imaged by super-resolution spectroscopy

    SciTech Connect

    King, John T.; Granick, Steve

    2016-06-21

    Super-resolution stimulated emission depletion microscopy is adapted here for materials characterization that would not otherwise be possible. With the example of organic lightemitting diodes (OLEDs), spectral imaging with pixel-by-pixel wavelength discrimination allows us to resolve local-chain environment encoded in the spectral response of the semiconducting polymer, and correlate chain packing with local electroluminescence by using externally applied current as the excitation source. We observe nanoscopic defects that would be unresolvable by traditional microscopy. They are revealed in electroluminescence maps in operating OLEDs with 50 nm spatial resolution. We find that brightest emission comes from regions with more densely packed chains. Conventional microscopy of an operating OLED would lack the resolution needed to discriminate these features, while traditional methods to resolve nanoscale features generally cannot be performed when the device is operating. Furthermore, this points the way towards real-time analysis of materials design principles in devices as they actually operate.

  19. Promising operational stability of high-efficiency organic light-emitting diodes based on thermally activated delayed fluorescence

    PubMed Central

    Nakanotani, Hajime; Masui, Kensuke; Nishide, Junichi; Shibata, Takumi; Adachi, Chihaya

    2013-01-01

    Organic light-emitting diodes (OLEDs) are attractive for next-generation displays and lighting applications because of their potential for high electroluminescence (EL) efficiency, flexibility and low-cost manufacture. Although phosphorescent emitters containing rare metals such as iridium or platinum produce devices with high EL efficiency, these metals are expensive and their blue emission remains unreliable for practical applications. Recently, a new route to high EL efficiency using materials that emit through thermally activated delayed fluorescence (TADF) was demonstrated. However, it is unclear whether devices that emit through TADF, which originates from the contributions of triplet excitons, are reliable. Here we demonstrate highly efficient, stable OLEDs that emit via TADF by controlling the position of the carrier recombination zone, resulting in projected lifetimes comparable to those of tris(2-phenylpyridinato)iridium(III)-based reference OLEDs. Our results indicate that TADF is intrinsically stable under electrical excitation and optimization of the surrounding materials will enhance device reliability. PMID:23820465

  20. Out-coupling membrane for large-size organic light-emitting panels with high efficiency and improved uniformity

    NASA Astrophysics Data System (ADS)

    Ding, Lei; Wang, Lu-Wei; Zhou, Lei; Zhang, Fang-hui

    2016-12-01

    An out-coupling membrane embedded with a scattering film of SiO2 spheres and polyethylene terephthalate (PET) plastic was successfully developed for 150 × 150 mm2 green OLEDs. Comparing with a reference OLED panel, an approximately 1-fold enhancement in the forward emission was obtained with an out-coupling membrane adhered to the surface of the external glass substrate of the panel. Moreover, it was verified that the emission color at different viewing angles can be stabilized without apparent spectral distortion. Particularly, the uniformity of the large-area OLEDs was greatly improved. Theoretical calculation clarified that the improved performance of the lighting panels is primarily attributed to the effect of particle scattering.

  1. Purely Organic Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes.

    PubMed

    Wong, Michael Y; Zysman-Colman, Eli

    2017-03-03

    The design of thermally activated delayed fluorescence (TADF) materials both as emitters and as hosts is an exploding area of research. The replacement of phosphorescent metal complexes with inexpensive organic compounds in electroluminescent (EL) devices that demonstrate comparable performance metrics is paradigm shifting, as these new materials offer the possibility of developing low-cost lighting and displays. Here, a comprehensive review of TADF materials is presented, with a focus on linking their optoelectronic behavior with the performance of the organic light-emitting diode (OLED) and related EL devices. TADF emitters are cross-compared within specific color ranges, with a focus on blue, green-yellow, orange-red, and white OLEDs. Organic small-molecule, dendrimer, polymer, and exciplex emitters are all discussed within this review, as is their use as host materials. Correlations are provided between the structure of the TADF materials and their optoelectronic properties. The success of TADF materials has ushered in the next generation of OLEDs.

  2. Very low resistance ZnS/Ag/ZnS/Ag/ZnS nano-multilayer anode for organic light emitting diodes applications.

    PubMed

    Kermani, Hamideh; Fallah, Hamid Reza; Hajimahmoodzadeh, Morteza; Tabatabaei, Seyed Vahid

    2013-02-01

    In this paper, design and simulation of conductive nanometric multilayer systems are discussed and optimum thickness of Ag and ZnS layers are calculated to reach simultaneously to high transmittance and low sheet resistance. The conductive transparent ZnS/Ag/ZnS/Ag/ZnS (ZAZAZ) nanometric multilayer systems are deposited on glass substrates at room temperature by a thermal evaporation method. The electrical, optical, and structural properties of these multilayers, such as sheet resistance, optical transmittance, and the root-mean-square surface roughness are obtained. High quality nanometric multilayer systems with sheet resistance of 2.7 Ω/sq and the optical transmittance of ~75.5% are obtained for the ZAZAZ system. Organic light emitting diodes (OLEDs) were fabricated and tested on the ZAZAZ anode. The ZAZAZ multilayer anode based OLED shows the performance comparable to that of the indium-tin oxide anode based OLED.

  3. Optically Detected Magnetic Resonance and Thermal Activation Spectroscopy Study of Organic Semiconductors

    SciTech Connect

    Kim, Chang-Hwan

    2003-01-01

    Organic electronic materials are a new class of emerging materials. Organic light emitting devices (OLEDs) are the most promising candidates for future flat panel display technologies. The photophysical characterization is the basic research step one must follow to understand this new class of materials and devices. The light emission properties are closely related to the transport properties of these materials. The objective of this dissertation is to probe the relation between transport and photophysical properties of organic semiconductors. The transport characteristics were evaluated by using thermally stimulated current and thermally stimulated luminescence techniques. The photoluminescence detected magnetic resonance and photoluminescence quantum yield studies provide valuable photophysical information on this class of materials. OLEDs are already in the market. However, detailed studies on the degradation mechanisms are still lacking. Since both optically detected magnetic resonance and thermal activation spectroscopy probe long-lived defect-related states in organic semiconductors, the combined study generates new insight on the OLED operation and degradation mechanisms.

  4. Aligning the Band Structures of Polymorphic Molybdenum Oxides and Organic Emitters in Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Yun, Jongmin; Jang, Woosun; Lee, Taehun; Lee, Yonghyuk; Soon, Aloysius

    2017-02-01

    Heavy transition-metal oxides are widely studied for key applications in electronics and energy technologies. In cutting-edge organic-light-emitting-diode (OLED) devices, there remain scientific challenges to achieve an efficient transfer of charges between electrodes and the organic layer. Recently, polymorphic MoO3 has been actively investigated to exploit its unique high work-function values, especially for its use in the electrode buffer layer to effectively transfer the charges in OLED devices. However, no systematic fundamental studies of its electronic structure are available. Thus, in this study, we use first-principles density-functional theory to investigate both the crystal structure and the electronic structure of the MoO3 polymorphs, and we conclude with a simple perspective to screen the best candidate for OLED applications via a hole transport-barrier descriptor.

  5. Highly efficient white top-emitting organic light-emitting diodes comprising laminated microlens films.

    PubMed

    Thomschke, Michael; Reineke, Sebastian; Lüssem, Björn; Leo, Karl

    2012-01-11

    White top-emitting organic light-emitting diodes (OLEDs) attract much attention, as they are optically independent from the substrate used. While monochrome top-emitting OLEDs can be designed easily to have high-emission efficiency, white light emission faces obstacles. The commonly used thin metal layers as top electrodes turn the device into a microresonator having detrimental narrow and angular dependent emission characteristics. Here we report on a novel concept to improve the color quality and efficiency of white top-emitting OLEDs. We laminate a refractive index-matched microlens film on the top-emitting device. The microlens film acts both as outcoupling-enhancing film and an integrating element, mixing the optical modes to a broadband spectrum.

  6. Organic electroluminescent structures for new generation of display systems

    NASA Astrophysics Data System (ADS)

    Ermakov, Oleg N.; Kaplunov, Michail G.; Efimov, Oleg N.; Stakharny, Sergey A.

    2007-05-01

    Brief history, modern state and development trends of organic electroluminescent structures technology (so-called OLED technology) are reviewed including research activities in this field in Russia. It's noted that OLED technology is one of the most promising newly emerging display technologies. Due to advantages of these devices (low power consumption, potential flexibility, wide color range) it is particularly well suited for small area display applications (micro displays) such as cell phones, virtual imaging systems, portable electronics. Experimental results for homemade blue light emitting OLED structures and hermetically sealed numeric displays are presented including photoluminescence (PL) and electroluminescence (EL ) current-voltage and brightness characteristics. It is noted that visible electroluminescence is observed at ultra low current level of nearly 1 μA, luminous efficiency exceeding 1 lm/W thus being nearly the same as for super bright inorganic inGaN/IGaN LEDs. Special attention is paid for destabilizing factors (temperature and degradation phenomena) influence on device characteristics.

  7. Fabrication of Organic Light-Emitting Diodes Using Photosynthetic Pigments Extracted from Spinach

    NASA Astrophysics Data System (ADS)

    Ohtani, Naoki; Kitagawa, Natsuko; Matsuda, Takashi

    2011-01-01

    We fabricated organic light-emitting diodes (OLEDs) containing chlorophylls in the active region, which were extracted from spinach using a chemical method. Photoluminescence (PL) cannot be observed in the thin film of the extracted chlorophylls owing to concentration quenching. To overcome the concentration quenching, a host material, poly[(m-phenylenevinylene)-alt-(2,5-dihexyloxy-p-phenylenevinylene)] (PPV) was added in the active region. This leads to the observaton of electroluminescence (EL) signals originating from chlorophyll a. We also evaluated the lifetime of the PL and EL. Consequently, the OLEDs containing carotenoids in the active region exhibit the light-emission much longer time than that without carotenoidos. This is assigned to the antioxidant activities of carotenoids. OLEDs containing a large amount of carotenoids are resistant to the oxidation damage.

  8. Solution-processed transparent blue organic light-emitting diodes with graphene as the top cathode

    PubMed Central

    Chang, Jung-Hung; Lin, Wei-Hsiang; Wang, Po-Chuan; Taur, Jieh-I; Ku, Ting-An; Chen, Wei-Ting; Yan, Shiang-Jiuan; Wu, Chih-I

    2015-01-01

    Graphene thin films have great potential to function as transparent electrodes in organic electronic devices, due to their excellent conductivity and high transparency. Recently, organic light-emitting diodes (OLEDs)have been successfully demonstrated to possess high luminous efficiencies with p-doped graphene anodes. However, reliable methods to fabricate n-doped graphene cathodes have been lacking, which would limit the application of graphene in flexible electronics. In this paper, we demonstrate fully solution-processed OLEDs with n-type doped multilayer graphene as the top electrode. The work function and sheet resistance of graphene are modified by an aqueous process which can also transfer graphene on organic devices as the top electrodes. With n-doped graphene layers used as the top cathode, all-solution processed transparent OLEDs can be fabricated without any vacuum process. PMID:25892370

  9. Light manipulation for organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Ou, Qing-Dong; Zhou, Lei; Li, Yan-Qing; Tang, Jian-Xin

    2014-10-01

    To realize high-efficiency organic light-emitting diodes (OLEDs), it is essential to boost out-coupling efficiency. Here we review our latest reports upon light manipulation for OLEDs by integrating a dual-side bio-inspired deterministic quasi-periodic moth's eye nanostructure with broadband anti-reflective and quasi-omnidirectional properties. Light out-coupling efficiency of OLEDs with stacked triple emission units is over 2 times that of a conventional device, resulting in drastic increase in external quantum efficiency and current efficiency to 119.7% and 366 cd A-1 without introducing spectral distortion and directionality. Theoretical calculations furthermore clarify that the improved device performance is primarily attributed to the effective extraction of the waveguide and surface plasmonic modes of the confined light over all the emission wavelengths and viewing-angles.

  10. In Vitro and In Vivo Effects of Natural Putative Secretagogues of Glucagon-Like Peptide-1 (GLP-1)

    PubMed Central

    Rafferty, Eamon P.; Wylie, Alastair R.; Elliott, Chris T.; Chevallier, Olivier P.; Grieve, David J.; Green, Brian D.

    2011-01-01

    Glucagon-like peptide-1 (GLP-1) is an intestinal hormone with well-established glucose-lowering activity. The in vitro and in vivo actions of natural putative secretagogues of GLP-1 were investigated. The acute GLP-1 releasing activity of olive leaf extract (OLE), glutamine (GLN), alpha casein (ACAS), beta casein (BCAS) and chlorogenic acid (CGA) were assessed in STC-1 cells and C57BL/6 mice. All compounds except ACAS significantly increased acute in vitro GLP-1 secretion (66–386%; P<0.05–0.001). Oral gavage of OLE and GLN modestly increased plasma GLP-1 concentrations (48% and 41%, respectively), but did not lower glycaemic excursions. OLE and GLN are potent stimulators of GLP-1 secretion both in vitro and in vivo and chronic studies should assess their suitability as nutritional therapies for type 2 diabetes. PMID:21886907

  11. Design and implementation of organic LED-based displays for signage application

    NASA Astrophysics Data System (ADS)

    Sharma, Pratibha; Kwok, Harry

    2006-06-01

    Organic light-emitting diodes (OLEDs) have been utilized successfully for various applications such as microdisplays in cell-phones and digital cameras. However, the application of OLEDs for large area signage displays has not yet been established. This paper presents novel design techniques for implementing OLEDs as light sources for signage application. The designs are examined on the basis of signage uniformity, cost and manufacturing complexity. Advantages and limitations of each design are described. It is determined that a trade-off is required to choose a design for implementation. After evaluation and comparison of the designs, the most optimal design is chosen and implemented. Measurement results with the optimal design are described.

  12. Efficient red, green, blue and white organic light-emitting diodes with same exciplex host

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Hao; Wu, Szu-Wei; Huang, Chih-Wei; Hsieh, Chung-Tsung; Lin, Sung-En; Chen, Nien-Po; Chang, Hsin-Hua

    2016-03-01

    Recently, exciplex had drawn attention because of its potential for efficient electroluminescence or for use as a host in organic light-emitting diodes (OLEDs). In this study, four kinds of hole transport material/electron transport material combinations were examined to verify the formation of exciplex and the corresponding energy bandgaps. We successfully demonstrated that the combination of tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 3,5,3‧,5‧-tetra(m-pyrid-3-yl)phenyl[1,1‧]biphenyl (BP4mPy) could form a stable exciplex emission with an adequate energy gap. Using exciplex as a host in red, green, and blue phosphorescent OLEDs with an identical trilayer architecture enabled effective energy transfer from exciplex to emitters, achieving corresponding efficiencies of 8.8, 14.1, and 15.8%. A maximum efficiency of 11.3% and stable emission was obtained in white OLEDs.

  13. Tetra-methyl substituted copper (II) phthalocyanine as a hole injection enhancer in organic light-emitting diodes

    SciTech Connect

    Wang, Yu-Long; Xu, Jia-Ju; Lin, Yi-Wei; Chen, Qian; Shan, Hai-Quan; Xu, Zong-Xiang E-mail: val.roy@cityu.edu.hk; Yan, Yan; Roy, V. A. L. E-mail: val.roy@cityu.edu.hk

    2015-10-15

    We have enhanced hole injection and lifetime in organic light-emitting diodes (OLEDs) by incorporating the isomeric metal phthalocyanine, CuMePc, as a hole injection enhancer. The OLED devices containing CuMePc as a hole injection layer (HIL) exhibited higher luminous efficiency and operational lifetime than those using a CuPc layer and without a HIL. The effect of CuMePc thickness on device performance was investigated. Atomic force microscope (AFM) studies revealed that the thin films were smooth and uniform because the mixture of CuMePc isomers depressed crystallization within the layer. This may have caused the observed enhanced hole injection, indicating that CuMePc is a promising HIL material for highly efficient OLEDs.

  14. An extremely low-index photonic crystal layer for enhanced light extraction from organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Shim, Yong Sub; Hwang, Ju Hyun; Park, Cheol Hwee; Jung, Sun-Gyu; Park, Young Wook; Ju, Byeong-Kwon

    2016-02-01

    This paper reports organic light-emitting diodes (OLEDs) with improved light extraction fabricated by embedding an extremely low-index photonic crystal (LIPC) layer. The LIPC layer increases the optical efficiency through the reduced wave-guide mode between the substrate and anode both by increased light resonance and by a strengthened diffraction effect from an extremely low-refractive-index medium, specifically a line structure composed of a vacuum gap. As a result, the current efficiency and power efficiency of the LIPC-OLEDs are 1.51 and 1.93 times higher, respectively, than the reference device at 1000 cd m-2. Because most of the light extraction is significant, especially in the forward direction, at the specific wavelengths satisfying the Bragg's diffraction equation, it is possible to calculate the anomalous spectrum of the LIPC-OLED through the finite-difference time domain (FDTD) method.This paper reports organic light-emitting diodes (OLEDs) with improved light extraction fabricated by embedding an extremely low-index photonic crystal (LIPC) layer. The LIPC layer increases the optical efficiency through the reduced wave-guide mode between the substrate and anode both by increased light resonance and by a strengthened diffraction effect from an extremely low-refractive-index medium, specifically a line structure composed of a vacuum gap. As a result, the current efficiency and power efficiency of the LIPC-OLEDs are 1.51 and 1.93 times higher, respectively, than the reference device at 1000 cd m-2. Because most of the light extraction is significant, especially in the forward direction, at the specific wavelengths satisfying the Bragg's diffraction equation, it is possible to calculate the anomalous spectrum of the LIPC-OLED through the finite-difference time domain (FDTD) method. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07312j

  15. Adalimumab treatment optimization for psoriasis: Results of a long-term phase 2/3 Japanese study.

    PubMed

    Asahina, Akihiko; Ohtsuki, Mamitaro; Etoh, Takafumi; Gu, Yihua; Okun, Martin M; Teixeira, Henrique D; Yamaguchi, Yuji; Nakagawa, Hidemi

    2015-11-01

    The tumor necrosis factor-α inhibitor, adalimumab, is approved to treat moderate-to-severe plaque psoriasis (40 mg every-other-week or 80 mg every-other-week following inadequate response at 40 mg in Japan). This open-label extension (OLE) trial evaluated the optimal adalimumab dose for long-term efficacy and safety in Japanese patients with moderate-to-severe plaque psoriasis following a prior 24-week, phase 2/3, randomized, double-blind study. Of the 169 patients from the phase 2/3 trial, 147 entered the OLE on 40 mg (n = 89) or 80 mg (n = 58) adalimumab every-other-week. Patients on 40 mg with Psoriasis Area and Severity Index (PASI) of less than 50 could escalate to 80 mg. At week 52 (28 of OLE), patients entering the OLE on 80 mg were reduced to 40 mg, with the option to re-escalate. For patients entering the OLE on 40 mg, final PASI 50/75/90 response rates were 85.1%/73.3%/60.4%, respectively, including effects of dose escalation. Among patients whose dose was escalated, final PASI 50/75/90 response rates were 70.0%/53.3%/36.7%, respectively. For patients entering the OLE on 80 mg, final PASI 50/75/90 response rates were 92.5%/84.9%/73.6%, respectively, including effects of dose re-escalation. Overall incidence rates of adverse events (AE) and injection-site reaction AE declined over time; rates for serious AE and infections were generally stable. Clinically meaningful efficacy of adalimumab was sustained to 4 years. Dose escalation to 80 mg every-other-week for patients with suboptimal response to 40 mg every-other-week, and dose reduction to 40 mg every-other-week for patients satisfactorily controlled on 80 mg every-other-week, are viable strategies for adalimumab optimization.

  16. Photophysics of thermally activated delayed fluorescence molecules

    NASA Astrophysics Data System (ADS)

    Dias, Fernando B.; Penfold, Thomas J.; Monkman, Andrew P.

    2017-03-01

    Thermally activated delayed fluorescence (TADF) has recently emerged as one of the most attractive methods for harvesting triplet states in metal-free organic materials for application in organic light emitting diodes (OLEDs). A large number of TADF molecules have been reported in the literature with the purpose of enhancing the efficiency of OLEDs by converting non-emissive triplet states into emissive singlet states. TADF emitters are able to harvest both singlets and triplet states through fluorescence (prompt and delayed), the latter due to the thermally activated reverse intersystem crossing mechanism that allows up-conversion of low energy triplet states to the emissive singlet level. This allows otherwise pure fluorescent OLEDs to overcome their intrinsic limit of 25% internal quantum efficiency (IQE), which is imposed by the 1:3 singlet–triplet ratio arising from the recombination of charges (electrons and holes). TADF based OLEDS with IQEs close to 100% are now routinely fabricated in the green spectral region. There is also significant progress for blue emitters. However, red emitters still show relatively low efficiencies. Despite the significant progress that has been made in recent years, still significant challenges persist to achieve full understanding of the TADF mechanism and improve the stability of these materials. These questions need to be solved in order to fully implement TADF in OLEDs and expand their application to other areas. To date, TADF has been exploited mainly in the field of OLEDs, but applications in other areas, such as sensing and fluorescence microscopies, are envisaged. In this review, the photophysics of TADF molecules is discussed, summarising current methods to characterise these materials and the current understanding of the TADF mechanism in various molecular systems.

  17. Elucidation of mechanisms underlying the protective effects of olive leaf extract against lead-induced neurotoxicity in Wistar rats.

    PubMed

    Seddik, Leila; Bah, Thierno Madjou; Aoues, Abdelkader; Slimani, Miloud; Benderdour, Mohamed

    2011-01-01

    Recently, we identified that olive leaf extract (OLE) prevents lead (Pb)-induced abnormalities in behavior and neurotransmitters production in chronic Pb exposure in rats. The aim of the present study was to provide additional evidence that OLE acts as an anti-apoptotic, anti-inflammatory, and antioxidant mediator in Pb exposed rats. 4-weeks old Wistar rats were exposed or not to 250 mg/l Pb for 13-weeks and then exposed to tap water containing or not 0.1% OLE for additional 2-weeks. Atomic absorption spectrophotometry showed significantly elevated Pb levels in the hippocampus and serum and reaches 5 and 42 µg/mg tissue, respectively. In the hippocampus, the examination of markers of apoptosis and inflammation revealed an increase in caspase-3 activity and DNA fragmentation as well as tumor necrosis factor alpha, interleukin-1 beta and prostaglandin E2 in Pb-exposed rats. In addition, our findings showed that Pb induced 4-hydroxynonenal production and inhibited antioxidant-related enzyme activity, such as glutathione-S-transferase as wells as energy metabolism-related enzyme activity, such as NADP-isocitrate dehydrogenase and glucose transporter. Upon examination of signaling pathways involved in apoptosis process, we found that Pb induced p38 mitogen activated protein kinase (MAPK) and Akt phosphorylation, but in contrast, inhibited that of ERK(1/2). Interestingly, OLE administration diminished tissue Pb deposition and prevented all Pb effects. In the frontal cortex, our data also showed that OLE-abolished Pb-induced caspase-3 activity and DNA fragmentation. Collectively, these data support the use of OLE by traditional medicine to counter Pb neurotoxicity.

  18. Wideband antireflective circular polarizer exhibiting a perfect dark state in organic light-emitting-diode display.

    PubMed

    Kim, Bong Choon; Lim, Young Jin; Song, Je Hoon; Lee, Jun Hee; Jeong, Kwang-Un; Lee, Joong Hee; Lee, Gi-Dong; Lee, Seung Hee

    2014-12-15

    We proposed wideband antireflective circular polarizer for realizing a true black state in all viewing directions in organic light-emitting-diode displays (OLEDs). Present commercialized wideband circular polarizer consisted of a half wave and a quarter wave plates having the refractive index parameter (Nz) of 1.5 in both films exhibits light leakage in the oblique viewing directions, deteriorating image quality of a black state. We evaluated Nzs of both films and proposed a new wideband antireflective circular polarizer with a perfect dark state in all viewing directions with Nz = 0.5 in both plates, which will greatly improve image quality of OLEDs.

  19. An Easy Approach to Control β-Phase Formation in PFO Films for Optimized Emission Properties.

    PubMed

    Zhang, Qi; Chi, Lang; Hai, Gang; Fang, Yueting; Li, Xiangchun; Xia, Ruidong; Huang, Wei; Gu, Erdan

    2017-02-18

    We demonstrate a novel approach to control β-phase content generated in poly(9,9-dioctylfluorene) (PFO) films. A very small amount of paraffin oil was used as the additive to the PFO solution in toluene. The β-phase fraction in the spin-coated PFO films can be modified from 0% to 20% simply by changing the volume percentage of paraffin oil in the mixed solution. Organic light emitting diodes (OLEDs) and amplified spontaneous emission (ASE) study confirmed low β-phase fraction promise better OLEDs device, while high β-phase fraction benefits ASE performance.

  20. A study on the evaporation process with multiple point-sources

    NASA Astrophysics Data System (ADS)

    Jun, Sunghoon; Kim, Minseok; Kim, Suk Han; Lee, Moon Yong; Lee, Eung Ki

    2013-10-01

    In Organic Light Emitting Display (OLED) manufacturing processes, there is a need to enlarge the mother glass substrate to raise its productivity and enable OLED TV. The larger the size of the glass substrate, the more difficult it is to establish a uniform thickness profile of the organic thin-film layer in the vacuum evaporation process. In this paper, a multiple point-source evaporation process is proposed to deposit a uniform organic layer uniformly. Using this method, a uniformity of 3.75% was achieved along a 1,300 mm length of Gen. 5.5 glass substrate (1300 × 1500 mm2).

  1. Structurally Integrated Photoluminescent Chemical and Biological Sensors: An Organic Light-Emitting Diode-Based Platform

    NASA Astrophysics Data System (ADS)

    Shinar, J.; Shinar, R.

    The chapter describes the development, advantages, challenges, and potential of an emerging, compact photoluminescence-based sensing platform for chemical and biological analytes, including multiple analytes. In this platform, the excitation source is an array of organic light-emitting device (OLED) pixels that is structurally integrated with the sensing component. Steps towards advanced integration with additionally a thin-film-based photodetector are also described. The performance of the OLED-based sensing platform is examined for gas-phase and dissolved oxygen, glucose, lactate, ethanol, hydrazine, and anthrax lethal factor.

  2. Charge injection and transport properties of an organic light-emitting diode

    PubMed Central

    Juhasz, Peter; Nevrela, Juraj; Micjan, Michal; Novota, Miroslav; Uhrik, Jan; Stuchlikova, Lubica; Jakabovic, Jan; Harmatha, Ladislav

    2016-01-01

    Summary The charge behavior of organic light emitting diode (OLED) is investigated by steady-state current–voltage technique and impedance spectroscopy at various temperatures to obtain activation energies of charge injection and transport processes. Good agreement of activation energies obtained by steady-state and frequency-domain was used to analyze their contributions to the charge injection and transport. We concluded that charge is injected into the OLED device mostly through the interfacial states at low voltage region, whereas the thermionic injection dominates in the high voltage region. This comparison of experimental techniques demonstrates their capabilities of identification of major bottleneck of charge injection and transport. PMID:26925351

  3. Interface modification and material synthesis of organic light-emitting diodes using plasma technology

    NASA Astrophysics Data System (ADS)

    Liang, Rongqing; Ou, Qiongrong; Yang, Cheng; He, Kongduo; Yang, Xilu; Zhong, Shaofeng; plasma application Team

    2015-09-01

    Organic light-emitting diodes (OLEDs), due to their unique properties of solution processability, compatibility with flexible substrates and with large-scale printing technology, attract huge interest in the field of lighting. The integration of plasma technology into OLEDs provides a new route to improve their performance. Here we demonstrate the modification of indium-tin-oxide (ITO) work function by plasma treatment, synthesis of thermally activated delayed fluorescence (TADF) materials using plasma grafting (polymerisation), and multi-layer solution processing achieved by plasma cross-linking.

  4. Effect of horizontal molecular orientation on triplet-exciton diffusion in amorphous organic films

    NASA Astrophysics Data System (ADS)

    Sawabe, T.; Takasu, I.; Yonehara, T.; Ono, T.; Yoshida, J.; Enomoto, S.; Amemiya, I.; Adachi, C.

    2012-09-01

    Triplet harvesting is a candidate technology for highly efficient and long-life white OLEDs, where green or red phosphorescent emitters are activated by the triplet-excitons diffused from blue fluorescent emitters. We examined two oxadiazole-based electron transport materials with different horizontal molecular orientation as a triplet-exciton diffusion layer (TDL) in triplet-harvesting OLEDs. The device characteristics and the transient electroluminescent analyses of the red phosphorescent emitter showed that the triplet-exciton diffusion was more effective in the highly oriented TDL. The results are ascribed to the strong orbital overlap between the oriented molecules, which provides rapid electron exchange (Dexter energy transfer) in the TDL.

  5. Eastern Kodak Company

    SciTech Connect

    Y.S. Tyan

    2009-06-30

    Lighting consumes more than 20% of electricity generated in the United States. Solid state lighting relies upon either inorganic or organic light-emitting diodes (OLEDs). OLED devices because of their thinness, fast response, excellent color, and efficiency could become the technology of choice for future lighting applications, provided progress is made to increase power efficiency and device lifetime and to develop cost-effective manufacturing processes. As a first step in this process, Eastman Kodak Company has demonstrated an OLED device architecture having an efficacy over 50 lm/W that exceeds the specifications of DOE Energy Star Program Requirements for Solid State Lighting. The project included work designed to optimize an OLED device, based on a stacked-OLED structure, with performance parameters of: low voltage; improved light extraction efficiency; improved internal quantum efficiency; and acceptable lifetime. The stated goal for the end of the project was delivery of an OLED device architecture, suitable for development into successful commercial products, having over 50 lum/W power efficiency and 10,000 hours lifetime at 1000 cd/m{sup 2}. During the project, Kodak developed and tested a tandem hybrid IES device made with a fluorescent blue emitter, a phosphorescent yellow emitter, and a phosphorescent red emitter in a stacked structure. The challenge was to find low voltage materials that do not absorb excessive amounts of emitted light when the extraction enhancement structure is applied. Because an extraction enhancement structure forces the emitted light to travel several times through the OLED layers before it is emitted, it exacerbates the absorption loss. A variety of ETL and HTL materials was investigated for application in the low voltage SSL device structure. Several of the materials were found to successfully yield low operating device voltages without incurring excessive absorption loss when the extraction enhancement structure was applied

  6. MoO3 as combined hole injection layer and tapered spacer in combinatorial multicolor microcavity organic light emitting diodes

    SciTech Connect

    Liu, R.; Xu, Chun; Biswas, Rana; Shinar, Joseph; Shinar, Ruth

    2011-09-01

    Multicolor microcavity ({mu}C) organic light-emitting diode (OLED) arrays were fabricated simply by controlling the hole injection and spacer MoO{sub 3} layer thickness. The normal emission was tunable from {approx}490 to 640 nm and can be further expanded. A compact, integrated spectrometer with two-dimensional combinatorial arrays of {mu}C OLEDs was realized. The MoO{sub 3} yields more efficient and stable devices, revealing a new breakdown mechanism. The pixel current density reaches {approx}4 A/cm{sup 2} and a maximal normal brightness {approx}140 000 Cd/m{sup 2}, which improves photoluminescence-based sensing and absorption measurements.

  7. Efficient Triplet Exciton Fusion in Molecularly Doped Polymer Light-Emitting Diodes.

    PubMed

    Di, Dawei; Yang, Le; Richter, Johannes M; Meraldi, Lorenzo; Altamimi, Rashid M; Alyamani, Ahmed Y; Credgington, Dan; Musselman, Kevin P; MacManus-Driscoll, Judith L; Friend, Richard H

    2017-04-01

    Solution-processed polymer organic light-emitting diodes (OLEDs) doped with triplet-triplet annihilation (TTA)-upconversion molecules, including 9,10-diphenylanthracene, perylene, rubrene and TIPS-pentacene, are reported. The fraction of triplet-generated electroluminescence approaches the theoretical limit. Record-high efficiencies in solution-processed OLEDs based on these materials are achieved. Unprecedented solid-state TTA-upconversion quantum yield of 23% (TTA-upconversion reaction efficiency of 70%) at electrical excitation well below one-sun equivalent is observed.

  8. Organic light emitting diodes with structured electrodes

    SciTech Connect

    Mao, Samuel S.; Liu, Gao; Johnson, Stephen G.

    2012-12-04

    A cathode that contain nanostructures that extend into the organic layer of an OLED has been described. The cathode can have an array of nanotubes or a layer of nanoclusters extending out from its surface. In another arrangement, the cathode is patterned and etched to form protruding nanostructures using a standard lithographic process. Various methods for fabricating these structures are provided, all of which are compatible with large-scale manufacturing. OLEDs made with these novel electrodes have greatly enhanced electron injection, have good environmental stability.

  9. Suppression of roll-off characteristics of organic light-emitting diodes by narrowing current injection/transport area to 50 nm

    SciTech Connect

    Hayashi, Kyohei Inoue, Munetomo; Yoshida, Kou; Nakanotani, Hajime; Mikhnenko, Oleksandr; Nguyen, Thuc-Quyen E-mail: adachi@cstf.kyushu-u.ac.jp; Adachi, Chihaya E-mail: adachi@cstf.kyushu-u.ac.jp

    2015-03-02

    Using e-beam nanolithography, the current injection/transport area in organic light-emitting diodes (OLEDs) was confined into a narrow linear structure with a minimum width of 50 nm. This caused suppression of Joule heating and partial separation of polarons and excitons, so the charge density where the electroluminescent efficiency decays to the half of the initial value (J{sub 0}) was significantly improved. A device with a narrow current injection width of 50 nm exhibited a J{sub 0} that was almost two orders of magnitude higher compared with that of the unpatterned OLED.

  10. Tuning charge balance in PHOLEDs with ambipolar host materials to achieve high efficiency

    SciTech Connect

    Padmaperuma, Asanga B.; Koech, Phillip K.; Cosimbescu, Lelia; Polikarpov, Evgueni; Swensen, James S.; Chopra, Neetu; So, Franky; Sapochak, Linda S.; Gaspar, Daniel J.

    2009-08-27

    The efficiency and stability of blue organic light emitting devices (OLEDs) continue to be a primary roadblock to developing organic solid state white lighting. For OLEDs to meet the high power conversion efficiency goal, they will require both close to 100% internal quantum efficiency and low operating voltage in a white light emitting device.1 It is generally accepted that such high quantum efficiency, can only be achieved with the use of organometallic phosphor doped OLEDs. Blue OLEDs are particularly important for solid state lighting. The simplest (and therefore likely the lowest cost) method of generating white light is to down convert part of the emission from a blue light source with a system of external phosphors.2 A second method of generating white light requires the superposition of the light from red, green and blue OLEDs in the correct ratio. Either of these two methods (and indeed any method of generating white light with a high color rendering index) critically depends on a high efficiency blue light component.3 A simple OLED generally consists of a hole-injecting anode, a preferentially hole transporting organic layer (HTL), an emissive layer that contains the recombination zone and ideally transports both holes and electrons, a preferentially electron-transporting layer (ETL) and an electron-injecting cathode. Color in state-of-the-art OLEDs is generated by an organometallic phosphor incorporated by co-sublimation into the emissive layer (EML).4 New materials functioning as hosts, emitters, charge transporting, and charge blocking layers have been developed along with device architectures leading to electrophosphorescent based OLEDs with high quantum efficiencies near the theoretical limit. However, the layers added to the device architecture to enable high quantum efficiencies lead to higher operating voltages and correspondingly lower power efficiencies. Achievement of target luminance power efficiencies will require new strategies for lowering

  11. Highly Simplified Tandem Organic Light-Emitting Devices Incorporating a Green Phosphorescence Ultrathin Emitter within a Novel Interface Exciplex for High Efficiency.

    PubMed

    Xu, Ting; Zhou, Jun-Gui; Huang, Chen-Chao; Zhang, Lei; Fung, Man-Keung; Murtaza, Imran; Meng, Hong; Liao, Liang-Sheng

    2017-03-17

    Herein we report a novel design philosophy of tandem OLEDs incorporating a doping-free green phosphorescent bis[2-(2-pyridinyl-N)phenyl-C](acetylacetonato)iridium(III) (Ir(ppy)2(acac)) as an ultrathin emissive layer (UEML) into a novel interface-exciplex-forming structure of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and 1,3,5-tri(p-pyrid-3-yl-phenyl)benzene (TmPyPB). Particularly, relatively low working voltage and remarkable efficiency are achieved and the designed tandem OLEDs exhibit a peak current efficiency of 135.74 cd/A (EQE = 36.85%) which is two times higher than 66.2 cd/A (EQE = 17.97%) of the device with a single emitter unit. This might be one of the highest efficiencies of OLEDs applying ultrathin emitters without light extraction. Moreover, with the proposed structure, the color gamut of the displays can be effectively increased from 76% to 82% NTSC if the same red and blue emissions as those in the NTSC are applied. A novel form of harmonious fusion among interface exciplex, UEML, and tandem structure is successfully realized, which sheds light on further development of ideal OLED structure with high efficiency, simplified fabrication, low power consumption, low cost, and improved color gamut, simultaneously.

  12. 50 CFR 300.117 - Prohibitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... assistance, including access as necessary to communications equipment, to CCAMLR inspectors. (g) Refuse to... issued pursuant to § 300.111. (m) Use any means or device that would reduce the size or obstruct the... vessel carries an OLE type-approved mobile transceiver unit and complies with the requirements...

  13. A versatile thermally activated delayed fluorescence emitter for both highly efficient doped and non-doped organic light emitting devices.

    PubMed

    Tsai, Wei-Lung; Huang, Ming-Hao; Lee, Wei-Kai; Hsu, Yi-Jiun; Pan, Kuan-Chung; Huang, Yi-Hsiang; Ting, Hao-Chun; Sarma, Monima; Ho, Yu-Yi; Hu, Hung-Chieh; Chen, Chung-Chia; Lee, Meng-Ting; Wong, Ken-Tsung; Wu, Chung-Chih

    2015-09-14

    A thermally activated delayed fluorescent (TADF) emitter (DMAC-TRZ) was reported either as the emitting dopant in a host or as the non-doped (neat) emitting layer to achieve high EL EQEs of up to 26.5% and 20% in OLEDs, respectively.

  14. Exploring the Potential of Nucleic Acid Bases in Organic Light Emitting Diodes

    DTIC Science & Technology

    2014-01-01

    biomaterials) that are renewable, inexpen- sive, ecologically safe, and with fi ne-tuned properties for poten- tial applications in electronic devices. Natural...electronics have the ultimate intention of creating “green electronics” that are Naturally occurring biomolecules have increasingly found...material properties , simplicity of use, and reduced cost indicate the promise of nucleobases for future OLED development. environmentally

  15. China’s Aircraft Carrier Dilemma

    DTIC Science & Technology

    2006-01-01

    nothing developed from them. Empresa Nacional Bazán, which merged with Astilleros Españoles S.A. (AESA) to form Navantia in 2000, reportedly attempted...acquisition and lengthy refurbishing seem to contradict the stated intention of its original buyer, Macao’s Agencia Turisticae Diversoes Chong Lot Limitada

  16. An Archeological Survey of Selected Federal Lands on the West Bank of the Big Bend/Lake Sharpe Project Area, Lyman and Stanley Counties, South Dakota, 1983: Supporting Documentation.

    DTIC Science & Technology

    1984-06-01

    MOUND, VILG , HBTIO, ET.) Buried Prehiatorie & Artifa-t- cartter CULTURAL AFFILIATIONS Unknown Prehistoric: Plains Villa~ Poe-otq -ole LOCATION SF)h...TYPE OF URAINS NO, VILG , HBTIO, EC)Artifact scatter CULTURAL AFFILIATIONS Unknown Prehistoric LOCATION NWh N NW~ NI& j SECTION__g_.. TOMNSHIP 4N

  17. Are Learning Style Preferences of Health Science Students Predictive of Their Attitudes towards E-Learning?

    ERIC Educational Resources Information Center

    Brown, Ted; Zoghi, Maryam; Williams, Brett; Jaberzadeh, Shapour; Roller, Louis; Palermo, Claire; McKenna, Lisa; Wright, Caroline; Baird, Marilyn; Schneider-Kolsky, Michal; Hewitt, Lesley; Sim, Jenny; Holt, Tangerine-Ann

    2009-01-01

    The objective for this study was to determine whether learning style preferences of health science students could predict their attitudes to e-learning. A survey comprising the "Index of Learning Styles" (ILS) and the "Online Learning Environment Survey" (OLES) was distributed to 2885 students enrolled in 10 different health…

  18. 78 FR 68134 - Sunshine Act Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-13

    ... at Ole Miss, Oxford, Mississippi. The public may comment on any agenda item or subject at a public... meeting will be called to order to consider the agenda items listed below. On-site registration will be... Board meeting. Status: Open. Agenda Chairman's Welcome Old Business Approval of minutes of August...

  19. Highly efficient bipolar connecting layers for tandem organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Niu, L.; Guan, Y.; Kong, C.; Cui, Y.; Ren, Y.; Tao, S.; Zhou, J.; Yu, J.

    2011-12-01

    A highly efficient tandem organic light-emitting device (OLED) has been fabricated by using an effective bipolar connecting layer structure. The connecting layers were made up of a layer of magnesium (Mg): 2,7-dipyrenyl-9,9-diphenyl fluorene (N-DPF) and a layer of tungsten trioxide (WO3). Such a connecting layer structure permits efficient opposite holes and electrons flowing into two adjacent emitting units. The current efficiency of the two-unit tandem device can be dramatically enhanced by more than four times compared with that of the conventional single-unit device. At 60 mA/cm2, the current efficiency of the tandem OLED using the connecting layers of Mg: N-DPF/WO3 was about 8.15 cd/A. The results can be marked as a breakthrough approach to improve the current efficiency and brightness of OLEDs. Furthermore, a model of the carrier tunneling into light-emitting units is proposed based on carrier balance and field-assisted tunneling. It indicates that the connecting layer structure functions as the origin of high efficiency for the tandem OLEDs.

  20. Theoretical investigation into optical and electronic properties of 1,8-naphthalimide derivatives.

    PubMed

    Jin, Ruifa; Tang, Shanshan

    2013-04-01

    A series of 1,8-naphthalimide derivatives has been designed to explore their optical, electronic, and charge transport properties as charge transport and/or luminescent materials for organic light-emitting diodes (OLEDs). The frontier molecular orbitals (FMOs) analysis have shown that the vertical electronic transitions of absorption and emission are characterized as intramolecular charge transfer (ICT) for electron-donating and aromatic groups substituted derivatives. However, the ICT character of the electron-withdrawing substituted derivatives is not significant. The calculated results show that their optical and electronic properties are affected by the substituent groups in 4-position of 1,8-naphthalimide. Our results suggest that 1,8-naphthalimide derivatives with electron-donating -OCH3 and -N(CH3)2 (1 and 2), electron-withdrawing -CN and-COCH3 (3 and 4), 2-(thiophen-2-yl)thiophene (5), 2,3-dihydrothieno[3,4-b][1, 4]dioxine (6), 2-phenyl-1,3,4-oxadiazole (7), and benzo[c][1,2,5]thiadiazole (8) fragments are expected to be promising candidates for luminescent materials for OLEDs, particularly for 5 and 7. In addition, 3 and 7 can be used as promising hole transport materials for OLEDs. This study should be helpful in further theoretical investigations on such kind of systems and also to the experimental study for charge transport and/or luminescent materials for OLEDs.

  1. Mulifunctional Dendritic Emitter: Aggregation-Induced Emission Enhanced, Thermally Activated Delayed Fluorescent Material for Solution-Processed Multilayered Organic Light-Emitting Diodes.

    PubMed

    Matsuoka, Kenichi; Albrecht, Ken; Yamamoto, Kimihisa; Fujita, Katsuhiko

    2017-01-31

    Thermally activated delayed fluorescence (TADF) materials emerged as promising light sources in third generation organic light-emitting diodes (OLED). Much effort has been invested for the development of small molecular TADF materials and vacuum process-based efficient TADF-OLEDs. In contrast, a limited number of solution processable high-molecular weight TADF materials toward low cost, large area, and scalable manufacturing of solution processed TADF-OLEDs have been reported so far. In this context, we report benzophenone-core carbazole dendrimers (GnB, n = generation) showing TADF and aggregation-induced emission enhancement (AIEE) properties along with alcohol resistance enabling further solution-based lamination of organic materials. The dendritic structure was found to play an important role for both TADF and AIEE activities in the neat films. By using these multifunctional dendritic emitters as non-doped emissive layers, OLED devices with fully solution processed organic multilayers were successfully fabricated and achieved maximum external quantum efficiency of 5.7%.

  2. In plane optical sensor based on organic electronic devices

    NASA Astrophysics Data System (ADS)

    Koetse, Marc; Rensing, Peter; van Heck, Gert; Sharpe, Ruben; Allard, Bart; Wieringa, Fokko; Kruijt, Peter; Meulendijks, Nicole; Jansen, Henk; Schoo, Herman

    2008-08-01

    Sensors based on organic electronic devices are emerging in a wide range of application areas. Here we present a sensor platform using organic light emitting diodes (OLED) and organic photodiodes (OPD) as active components. By means of lamination and interconnection technology the functional foils with OLED and OPD arrays form an in-plane optical sensor platform (IPOS). This platform can be extended with a wireless data and signal processing unit yielding a sensor node. The focus of our research is to engage the node in a healthcare application, in which a bandage is able to monitor the vital signs of a person, a so-called Smart Bandage. One of the principles that is described here is based on measuring the absorption modulation of blood volume induced by the pulse (photoplethysmography). The information from such a bandage could be used to monitor wound healing by measuring the perfusion in the skin. The OLED and OPD devices are manufactured on separate foils and glass substrates by means of printing and coating technologies. Furthermore, the modular approach allows for the application of the optical sensing unit in a variety of other fields including chemical sensing. This, ultimately enables the measurement of a large variety of physiological parameters using the same bandage and the same basic sensor architecture. Here we discuss the build-up of our device in general terms. Specific characteristics of the used OLEDs and OPDs are shown and finally we demonstrate the functionality by simultaneously recorded photoplethysmograms of our device and a clinical pulseoximeter.

  3. Installation Restoration Program. Expanded Site Investigation Report. 148th Combat Communications Squadron, Ontario Air National Guard Station, California Air National Guard, Ontario, California

    DTIC Science & Technology

    1993-11-01

    readig baIIIIn redig NAntaaye •AAt#pji4, -r,9 Borehole Log3 (Condmistio sh"n) Sorehols Location: AW CA:-rtd-v CA Ckv h Bor ~ole 4 , ae 41ý . Iri *j...afle the samples were analyzed. Both of theme procedures ar not considered to be good labonaory pracdaes. TF4TATPIVLY W TUFIM COMPOUNDS: No

  4. Accurate optical simulation of nano-particle based internal scattering layers for light outcoupling from organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Egel, Amos; Gomard, Guillaume; Kettlitz, Siegfried W.; Lemmer, Uli

    2017-02-01

    We present a numerical strategy for the accurate simulation of light extraction from organic light emitting diodes (OLEDs) comprising an internal nano-particle based scattering layer. On the one hand, the light emission and propagation through the OLED thin film system (including the scattering layer) is treated by means of rigorous wave optics calculations using the T-matrix formalism. On the other hand, the propagation through the substrate is modeled in a ray optics approach. The results from the wave optics calculations enter in terms of the initial substrate radiation pattern and the bidirectional reflectivity distribution of the OLED stack with scattering layer. In order to correct for the truncation error due to a finite number of particles in the simulations, we extrapolate the results to infinitely extended scattering layers. As an application example, we estimate the optimal particle filling fraction for an internal scattering layer in a realistic OLED geometry. The presented treatment is designed to emerge from electromagnetic theory with as few additional assumptions as possible. It could thus serve as a baseline to validate faster but approximate simulation approaches.

  5. "GodMode Is His Video Game Name": Situating Learning and Identity in Structures of Social Practice

    ERIC Educational Resources Information Center

    Bricker, Leah A.; Bell, Philip

    2012-01-01

    In this paper, we report on the structural nexus of one youth's gaming practices across contexts and over time. We utilize data from an ethnography of youth science and technology learning, as well as expertise development, across settings and developmental time. We use Ole Dreier's theory of persons to understand how this youth is able to develop…

  6. Voodoo Dolls, Charms, and Spells in the Classroom: Teaching, Screening, and Deconstructing the Misrepresentation of the African Religion

    ERIC Educational Resources Information Center

    Reuber, Alexandra

    2011-01-01

    "New Orleans voodoo," also called "créole voodoo," is an amalgamation of an honoring of the spirits of the dead, a respect for the elderly and the spiritual life, African knowledge of herbs and charms, and European elements of Catholicism. It is a religion of ancestor worship that is unknown to us, and that we are not…

  7. Particle Distributions and Laser-Particle Interactions in an RF Discharge of Silane.

    DTIC Science & Technology

    1985-11-20

    PROGRAM ELEMENT PROJECT. TASK AREA 6 WORK UNIT NUMBERS Northwiestern University, Department of Chemistry NR 056-729 11. CONTROLLING OFFICE MAMIE AND...AGENCY NAME A AOORESS(Ui different ce C4M~u.ind Office) It. SECURITY CLASS. (of Ole #%wf) ONR, Chicago 536 South Clark Street Unclassified Chicago

  8. Direct evidence of molecular aggregation and degradation mechanism of organic light-emitting diodes under joule heating: an STM and photoluminescence study.

    PubMed

    Gong, Jian-Ru; Wan, Li-Jun; Lei, Sheng-Bin; Bai, Chun-Li; Zhang, Xiao-Hong; Lee, Shuit-Tong

    2005-02-10

    The Joule heating effect on electroluminescent efficiency is important in the degradation origin of organic light-emitting diodes (OLED). Scanning tunneling microscopy (STM) and photoluminescence (PL) measurements were performed on the guest molecule BT (1,4-bis(benzothiazole-vinyl) benzene), host molecule TPBI (2, 2',2' '-(1,3,5-phenylene)tris-[1-phenyl-1H-benzimidazole]), and their mixture deposited on an HOPG surface to study the OLED degradation mechanism due to thermal heating. At room temperature, BT and TPBI in the mixed layer show good compatibility and high PL intensity, but at higher temperatures, they show phase separation and aggregation into their own domains and a concomitant decrease in PL intensity. The PL intensity loss suggests ineffective energy transfer from TPBI to BT due to phase separation, which may cause OLED degradation. Scanning tunneling spectroscopy (STS) results show that the band gaps of TPBI and BT remain unchanged with the annealing temperature, suggesting that the heat-induced decay of OLED is related to the interfacial structural change rather than the respective molecular band gap. The results provide direct evidence showing how the molecular structures of the mixed layer vary and affect the PL intensity due to temperature.

  9. 50 CFR 404.5 - Requirements for a vessel monitoring system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... NORTHWESTERN HAWAIIAN ISLANDS MARINE NATIONAL MONUMENT § 404.5 Requirements for a vessel monitoring system. (a... deemed appropriate by OLE. (g) Activities Regarding Vessel Monitoring Systems. Effective August 28, 2006, the following activities regarding vessel monitoring systems are prohibited and thus unlawful for...

  10. Development of a Run Time Math Library for the 1750A Airborne Microcomputer.

    DTIC Science & Technology

    1985-12-01

    ORTE: 18 JULY 1985 * * VERSION: 1.0 * * NIrE: CosF * * ?OLE NUMBER: 1.0 * * ESCRIPTION: " This function is invoked to computo the...FixToChaor * * MODULE NUBE : 1.0 * * DESCRIPTIOI: * * This routine is used to convert fixed-point values into * dl mactar representation. This routine

  11. Nanohybrids of Mg/Al layered double hydroxide and long-chain (C18) unsaturated fatty acid anions: Structure and sorptive properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-chain (C18) unsaturated fatty acid anions, elaidate (ELA), oleate (OLE), linoleate (LINO), and linolenate (LINOLEN), were intercalated into Mg/Al (3:1) layered double hydroxide (LDH) and the resultant organo-LDH nanohybrid materials were characterized and subsequently evaluated as sorbents of s...

  12. 76 FR 63281 - Submission for OMB Review; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ... Assessment Program Laboratory Application. OMB Control Number: 0693-0053. Form Number(s): None. Type of... equipment. To perform these assessments, and continue the program, NIST needs to be able to collect... program involves NIST (Office of Law Enforcement Standards-OLES) experts assessing...

  13. High prevalence of vitamin D insufficiency among elite Spanish athletes the importance of outdoor training adaptation.

    PubMed

    Valtueña, Jara; Dominguez, D; Til, L; González-Gross, M; Drobnic, F

    2014-07-01

    INTRODUCCIÓN: En los últimos años, el descubrimiento de receptores musculares para la vitamina D sugiere un papel significativo de esta vitamina en el tejido muscular, adquiriendo una relevancia especial en deportistas. No existen apenas datos disponibles acerca de las concentraciones de vitamina D en deportistas de élite Españoles.

  14. [The role of BCP in electroluminescence of multilayer organic light-emitting devices].

    PubMed

    Deng, Zhao-Ru; Yang, Sheng-Yi; Lou, Zhi-Dong; Meng, Ling-Chuan

    2009-03-01

    As a hole-blocking layer, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is usually used in blue and white light electroluminescent devices. The ability of blocking holes of BCP layer depends on its thickness, and basically holes can tunnel through thin BCP layer. In order to know the role of BCP layer in electroluminescence (EL) of multilayer organic light-emitting diodes (OLEDs), in the present paper, the authors designed a multilayer OLED ITO/NPB/BCP/Alq3 : DCJTB/Alq3/Al and investigated the influence of thickness of BCP on the EL spectra of multilayer OLEDs at different applied voltages. The experimental data show that thin BCP layer can block holes partially and tune the energy transfer between different emissive layers, and in this way, it is easy to obtain white emission, but its EL spectra will change with the applied voltages. The EL spectra of multilayer device will remain relatively stable when BCP layer is thick enough, and the holes can hardly tunnel through when the thickness of BCP layer is more than 15 nm. Furthermore, the stability of EL spectra of the multilayer OLED at different applied voltages was discussed.

  15. Tailoring Directive Gain for High-Contrast, Wide-Viewing-Angle Organic Light-Emitting Diodes Using Speckle Image Holograpy Metasurfaces.

    PubMed

    Zhou, Lei; Ou, Qing-Dong; Shen, Su; Zhou, Yun; Fan, Yuan-Yuan; Zhang, Jun; Tang, Jian-Xin

    2016-08-31

    Holography metasurfaces have been used to control the propagation of light to an unprecedented level, exhibiting the immense potential for light steering in organic light-emitting diodes (OLEDs). Here, a new approach to tailoring directive gain for high contrast, wide-viewing-angle OLEDs is proposed by implementing a spcekle image holography (SIH) metasurface. The experimental and theoretical results provide the direct proofs that the SIH metasurface can play very important roles not only in releasing the trapped energy flow insides the devices but also in tailoring the wavefronts to the preferred patterns due to its "regional orientation" k-vectors patterns. The resulting power efficiency and external quantum efficiency of the OLEDs using a SIH metasurface are 1.97 and 1.95 times that of the reference device with a standard architecture. Furthermore, the wavefronts of emitted light are delicately modulated in a polarization-independent manner, yielding 2.5 times higher contrast ratio compared to the reference device. This unique engineered directive gain property is also well-retained for the viewing angles varing from normal to titled ±60° without spectral distortion. These results enrich the understanding of light wavefronts control in OLEDs and highlight its potential application in display as well as light steering for other optoelectronics.

  16. Solid-State Lighting R&D Plan - 2015

    SciTech Connect

    Bardsley, Norman; Bland, Stephen; Hansen, Monica; Pattison, Lisa; Pattison, Morgan; Stober, Kelsey; Yamada, Mary

    2015-05-28

    Provides analysis and direction for ongoing R&D activities to advance SSL technology and increase energy savings, reviewing SSL technology status and trends for both LEDs and OLEDs and offering an overview of the current DOE SSL R&D project portfolio.

  17. Low-temperature gas-barrier films by atomic layer deposition for encapsulating organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Tseng, Ming-Hung; Yu, Hui-Huan; Chou, Kun-Yi; Jou, Jwo-Huei; Lin, Kung-Liang; Wang, Chin-Chiun; Tsai, Feng-Yu

    2016-07-01

    Dependences of gas-barrier performance on the deposition temperature of atomic-layer-deposited (ALD) Al2O3, HfO2, and ZnO films were studied to establish low-temperature ALD processes for encapsulating organic light-emitting diodes (OLEDs). By identifying and controlling the key factors, i.e. using H2O2 as an oxidant, laminating Al2O3 with HfO2 or ZnO layers into AHO or AZO nanolaminates, and extending purge steps, OLED-acceptable gas-barrier performance (water vapor transmission rates ˜ 10-6 g m-2 d-1) was achieved for the first time at a low deposition temperature of 50 °C in a thermal ALD mode. The compatibility of the low-temperature ALD process with OLEDs was confirmed by applying the process to encapsulate different types of OLED devices, which were degradation-free upon encapsulation and showed adequate lifetime during accelerated aging tests (pixel shrinkage <5% after 240 h at 60 °C/90% RH).

  18. Light conversion efficiency of top-emitting organic light-emitting diode structure.

    PubMed

    Lee, Hyeongi; Won, Taeyoung

    2014-11-01

    Top-emitting organic light-emitting diodes (OLEDs) with a microcavity structure are presented in this paper. We performed a finite element (FE) analysis of a trilayer OLED that was inserted between the reflective layer and the semi-reflective layer of a device. We carried out an optical analysis of this OLED device and calculated the optimal width between the reflective layer and the semi-reflective layer to consider the microcavity effect. Our simulation revealed that the thickness of each layer can affect the recombination rate at the emission layer. We used five OLED devices. Device A is a reference device with a 42.5 nm hole transport layer (HTL), a 15 nm emission layer (EML) and a 45 nm electron transport layer (ETL). We varied the thickness of the HTL of Device A to 20 nm and 65 nm, and designated these devices as Device B and Device C, respectively. We also varied the thickness of the ETL of Device A to 20 nm and 65 nm, and designated these devices as Device D and Device E, respectively. As the thickness of the HTL and the ETL are decreased, a higher recombination rate is achieved. However, the highest recombination rate does not necessarily correspond to the highest external quantum efficiency (EQE) owing to the resonance effect. Our simulation revealed that the overall thickness of the device seems to be a more significant factor owing to the path of light.

  19. A Light Scattering Layer for Internal Light Extraction of Organic Light-Emitting Diodes Based on Silver Nanowires.

    PubMed

    Lee, Keunsoo; Shin, Jin-Wook; Park, Jun-Hwan; Lee, Jonghee; Joo, Chul Woong; Lee, Jeong-Ik; Cho, Doo-Hee; Lim, Jong Tae; Oh, Min-Cheol; Ju, Byeong-Kwon; Moon, Jaehyun

    2016-07-13

    We propose and fabricate a random light scattering layer for light extraction in organic light-emitting diodes (OLEDs) with silver nanodots, which were obtained by melting silver nanowires. The OLED with the light scattering layer as an internal light extraction structure was enhanced by 49.1% for the integrated external quantum efficiency (EQE). When a wrinkle structure is simultaneously used for an external light extraction structure, the total enhancement of the integrated EQE was 65.3%. The EQE is maximized to 65.3% at a current level of 2.0 mA/cm(2). By applying an internal light scattering layer and wrinkle structure to an OLED, the variance in the emission spectra was negligible over a broad viewing angle. Power mode analyses with finite difference time domain (FDTD) simulations revealed that the use of a scattering layer effectively reduced the waveguiding mode while introducing non-negligible absorption. Our method offers an effective yet simple approach to achieve both efficiency enhancement and spectral stability for a wide range of OLED applications.

  20. Shortening and Angulation for Soft-Tissue Reconstruction of Extremity Wounds in a Combat Support Hospital

    DTIC Science & Technology

    2009-08-01

    until future definitive reconstructive procedures can be performed. In the setting of an amputation without the aid of a prosthesis . little improve...142 8. tl Ncudcck I . Klac’ W. Continuou’ skm expanS~nn for cmcnng ;.olt ’’"lu: dclcch of the foot ’ole. Unfallchirurg 1995: 9H( I): 40 -1 ~4