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Sample records for ito substrate modification

  1. ITO DBR electrodes fabricated on PET substrate for organic electronics.

    PubMed

    Tien, W C; Chu, A K

    2014-02-24

    A conductive distributed Bragg reflector (DBR) fabricated on PET substrate using the single indium tin oxide (ITO) material is proposed. The large index contrast of the DBRs was obtained by depositing alternating layers of dense and porous ITO films. The high refractive index of the dense ITO films was achieved by long-throw radio-frequency magnetron sputtering technique at room temperature. On the other hand, the porous ITO films with low refractive index were fabricated by supercritical CO2 (SCCO2) treatment at 60 °C. The index contrast of the dense and porous ITO films as larger as 0.59 at blue spectral range was obtained. For the 4.5-period ITO DBR fabricated on PET substrate, the reflectance and sheet resistance of 85.1% and 47 Ω/◻ were achieved at 475 nm. PMID:24663715

  2. Flexible OLED fabrication with ITO thin film on polymer substrate

    NASA Astrophysics Data System (ADS)

    Kim, Sung Il; Lee, Kyo Woong; Bhusan Sahu, Bibhuti; Geon Han, Jeon

    2015-09-01

    This paper reports the synthesis of flexible indium tin oxide (ITO) films in a dual pulse magnetron sputtering (DPMS) system at low temperature (<100 °C) deposition condition. This study also presents experimental demonstration of the ITO films for their possible use in the fabrication of organic light emitting diode (OLED) device, and the device performance on the super polycarbonate substrates. The presented data reveals the feasibility of ITO films, with a very low sheet resistance of ∼30 Ω/□ and high transmittance of ∼88% at 550 nm, simply by the magnetron pulse mode operations with increasing pulse frequency from 0 to 50 kHz.

  3. Modification and Wettability Study ITO Glass Coated with ZnO Film by Electrochemical Deposition and Hydrothermal Deposition.

    PubMed

    Fang, Mei; Zou, Changwei; Gong, Manfeng

    2016-03-01

    ITO glass is a substrate often utilized to construct various IT devices and sensors, favored for its excellent characteristics such as rapid electron transfer kinetics, non-toxicity, chemical stability, and high electron transmission. In this paper, film with ZnO-modified nanostructures on ITO glass was fabricated by both electrochemical deposition and hydrothermal deposition, respectively. The ZnO film as-deposited was then modified by surface modification reagent (FOTMS) to obtain a hydrophobic surface. SEM, XRD, and ZYGO were used to characterize their properties. The contact angles were then measured to characterize and compare the wettability of non-modified ITO glass and ITO glass modified by zinc oxide films. PMID:27455756

  4. Effects O2 plasma surface treatment on the electrical properties of the ITO substrate

    NASA Astrophysics Data System (ADS)

    Hong, Jin-Woong; Oh, Dong-Hoon; Shim, Sang-Min; Lee, Young-Sang; Kang, Yong-Gil; Shin, Jong-Yeol

    2012-05-01

    The indium-tin-oxide (ITO) substrate is used as a transparent electrode in organic light-emitting diodes (OLEDs) and organic photovoltaic cells. The effect of an O2 plasma surface treatment on the electrical properties of the ITO substrate was examined. The four-point probe method, an atomic force microscope (AFM), a LCR meter, a Cole-Cole plot, and a conductive mechanism analysis were used to assess the properties of the treated ITO substrates. The four-point probe method and the AFM study revealed a lower ITO surface resistance of 17.6 Ω/sq and an average roughness of 2 nm, respectively, for a substrate treated by a plasma at 250 W for 40 s. The lower surface resistance of the ITO substrate treated at 250 W for 40 s was confirmed by using a LCR meter. An amorphous fluoropolymer (AF) was deposited on an ITO substrate treated under the optimal conditions and on a non-plasma treated ITO substrate as well. The potential barriers for charge injection in these devices were 0.25 eV and 0.15 eV, respectively, indicating a 0.1-eV decrease due to the plasma treatment.

  5. Optical characterization of deposited ITO thin films on glass and PET substrates

    NASA Astrophysics Data System (ADS)

    Elmas, Saliha; Korkmaz, Şadan; Pat, Suat

    2013-07-01

    This work focuses on fabrication, characterization and understanding some physical properties of transparent and conductive ITO thin films. ITO thin films were deposited onto glass and polyethylene terephthalate (PET) substrates by thermionic vacuum arc (TVA) technique. TVA is a different technology for thin film deposition. Thicknesses and refractive indices of the ITO thin films have been determined by spectroscopic ellipsometry (SE) technique using Cauchy model for fitting. SE is a novel, nondestructive and powerful technique to investigate the optical characteristics of materials. Especially thickness and optical constants are measuring this device. Transmittances, reflectance of ITO coated samples were measured by UV-vis spectrophotometer and interferometer, respectively. The optical method was used to determine the band gaps of ITO thin films. Surface morphologies of produced films were characterized by atomic force microscope (AFM) for surface topography and roughness of ITO thin films. Resistivity measurements show that produced films show semiconductor properties.

  6. Improvement of organic solar cells by flexible substrate and ITO surface treatments

    NASA Astrophysics Data System (ADS)

    Cheng, Yuang-Tung; Ho, Jyh-Jier; Wang, Chien-Kun; Lee, William; Lu, Chih-Chiang; Yau, Bao-Shun; Nain, Jhen-Liang; Chang, Shun-Hsyung; Chang, Chiu-Cheng; Wang, Kang L.

    2010-10-01

    In this paper, surface treatments on polyethylene terephthalate with polymeric hard coating (PET-HC) substrates are described. The effect of the contact angle on the treatment is first investigated. It has been observed that detergent is quite effective in removing organic contamination on the flexible PET-HC substrates. Next, using a DC-reactive magnetron sputter, indium tin oxide (ITO) thin films of 90 nm are grown on a substrate treated by detergent. Then, various ITO surface treatments are made for improving the performance of the finally developed organic solar cells with structure Al/P3HT:PCBM/PEDOT:PSS/ITO/PET. It is found that the parameters of the ITO including resistivity, carrier concentration, transmittance, surface morphology, and work function depended on the surface treatments and significantly influence the solar cell performance. With the optimal conditions for detergent treatment on flexible PET substrates, the ITO film with a resistivity of 5.6 × 10 -4 Ω cm and average optical transmittance of 84.1% in the visible region are obtained. The optimal ITO surface treated by detergent for 5 min and then by UV ozone for 20 min exhibits the best WF value of 5.22 eV. This improves about 8.30% in the WF compared with that of the untreated ITO film. In the case of optimal treatment with the organic photovoltaic device, meanwhile, 36.6% enhancement in short circuit current density ( Jsc) and 92.7% enhancement in conversion efficiency ( η) over the untreated solar cell are obtained.

  7. Thickness Dependence of Properties of ITO Films Deposited on PET Substrates.

    PubMed

    Kim, Seon Tae; Kim, Tae Gyu; Cho, Hyun; Yoon, Su Jong; Kim, Hye Sung; Kim, Jin Kon

    2016-02-01

    Indium tin oxide (ITO) films with various thicknesses from 104 nm to 513 nm were prepared onto polyethylene terephthalate (PET) substrates by using r.f. magnetron sputtering without intentionally heating the substrates. The structural, optical, and electrical properties of ITO films were investigated as a function of film thickness. It was found that the amorphous nature of the ITO film was dominant below the thickness of about 200 nm but the degree of the crystallinity increased with an increasing thickness above the thickness of about 250 nm, resulting in the increase of carrier concentration and therefore reducing the electrical resistivity from 5.1 x 10(-3) to 9.4 x 10(-4) omega x cm. The average transmittance (400-800 nm) of the ITO deposited PET substrates decreased as the film thickness was increasing and was above 80% for the thickness below 315 nm. The results show that the improvement of the film crystallinity with the film thickness contributes to the increase of the carrier concentration and the enhancement of the electrical conductivity. PMID:27433686

  8. Excimer ablation of ITO on flexible substrates for large format display applications

    NASA Astrophysics Data System (ADS)

    Ghandour, Osman A.; Constantinide, Dan; Sheets, Ronald E.

    2002-06-01

    Excimer-based ablative patterning of Indium Tin Oxide (ITO) thin film on flexible substrates has been evaluated for large format display applications. In display package manufacturing, excimer-based ITO ablation can provide a great advantage over conventional photolithographic processing. It can eliminate many steps from the manufacturing cycle, resulting in significant cost reduction. Flexible substrate display packaging is desirable for at least two reasons. It allows roll-to-roll low cost, large volume manufacturing. Its low weight provides for an easy scale up to larger format displays. An XeCl excimer, 1x, amplitude mask pattern projection, scan-and-repeat system was utilized in the evaluation work. The mask pattern had line groupings of line-widths varying from 8 to 30 micrometers with line length of 44 mm. Lines from all the groupings were simultaneously ablated in 150 nm-thick ITO layer on a flexible 100 micrometers thick Polyethylene terephtalate (PET) substrate using scanning with optimized dwell duration of 10 pulses and optimized fluence level of 350 mJ/cm2. Lines ablated with mask line groupings of line-width greater than or equal to 11 micrometers showed complete electrical isolation indicating complete ITO removal. Scanning electron Microscopy (SEM) showed the presence of a slight curling effect at ablated line edges. The effect was studied as a function of wavelength and imaging resolution. A CO2 cleaning method was evaluated for removing the extruding curled material.

  9. Electrochemical detection of nitrite on poly(pyronin Y)/graphene nanocomposites modified ITO substrate

    NASA Astrophysics Data System (ADS)

    Şinoforoğlu, Mehmet; Dağcı, Kader; Alanyalıoğlu, Murat; Meral, Kadem

    2016-06-01

    The present study reports on an easy preparation of poly(pyronin Y)/graphene (poly(PyY)/graphene) nanocomposites thin films on indium tin oxide coated glass substrates (ITO). The thin films of poly(PyY)/graphene nanocomposites are prepared by a novel method consisting of three steps; (i) preparation of graphene oxide (GO) thin films on ITO by spin-coating method, (ii) self-assembly of PyY molecules from aqueous solution onto the GO thin film, (iii) surface-confined electropolymerization (SCEP) of the adsorbed PyY molecules on the GO thin film. The as-prepared poly(PyY)/graphene nanocomposites thin films are characterized by using electroanalytical and spectroscopic techniques. Afterwards, the graphene-based polymeric dye thin film on ITO is used as an electrode in an electrochemical cell. Its performance is tested for electrochemical detection of nitrite. Under optimized conditions, the electrocatalytical effect of the nanocomposites thin film through electrochemical oxidation of nitrite is better than that of GO coated ITO.

  10. A sensitive plasmonic copper(II) sensor based on gold nanoparticles deposited on ITO glass substrate.

    PubMed

    Ding, Lijun; Gao, Yan; Di, Junwei

    2016-09-15

    Gold nanoparticles (Au NPs) based plasmonic probe was developed for sensitive and selective detection of Cu(2+) ion. The Au NPs were self-assembled on transparent indium tin oxide (ITO) film coated glass substrate using poly dimethyl diallyl ammonium chloride (PDDA) as a linker and then calcined at 400°C to obtain pure Au NPs on ITO surface (ITO/Au NPs). The probe was fabricated by functionalizing l-cysteine (Cys) on to gold surface (ITO/Au NPs/Cys). The strong chelation of Cu(2+) with Cys formed a stable Cys-Cu complex, and resulted in the red-shift of localized surface plasmon resonance (LSPR) peak of the Au NPs. The introduction of bovine serum albumin (BSA) as the second complexant could form complex of Cys-Cu-BAS and further markedly enhanced the red-shift of the LSPR peak. This plasmonic probe provided a highly sensitive and selective detection towards Cu(2+) ions, with a wide linear detection range (10(-11)-10(-5)M) over 6 orders of magnitude. The simple and cost-effective probe was successfully applied to the determination of Cu(2+) in real samples. PMID:27093484

  11. Characteristic difference between ITO/ZrCu and ITO/Ag bi-layer films as transparent electrodes deposited on PET substrate

    NASA Astrophysics Data System (ADS)

    Lee, C. J.; Lin, H. K.; Sun, S. Y.; Huang, J. C.

    2010-10-01

    The metallic-glass film of ZrCu layer deposited by co-sputtering was utilized as the metallic layer in the bi-layer structure transparent conductive electrode of ITO/ZrCu (IZC) deposited on the PET substrate using magnetron sputtering at room temperature. In addition, the pure Ag metal layer was applied in the same structure of transparent conductive film, ITO/Ag, in comparison with the IZC film. The ZrCu layer could form a continuous and smooth film in thickness lower than 6 nm, compared with the island structure of pure Ag layer of the same thickness. The 30 nm ITO/3 nm ZrCu films could show the optical transmittance of 73% at 550 nm wavelength. The 30 nm ITO/12 nm ZrCu films could show the better sheet resistance of 20 Ω/sq, but it was still worse than that of the ITO/Ag films. It was suggested that an alloy system with lower resistivity and negative mixing heat between atoms might be another way to form a continuous layer in thickness lower than 6 nm for metal film.

  12. Effects of substrate temperature on properties of ITO-ZnO composition spread films fabricated by combinatorial RF magnetron sputtering

    SciTech Connect

    Heo, Gi-Seok; Gim, In-Gi; Park, Jong-Woon; Kim, Kwang-Young; Kim, Tae-Won

    2009-10-15

    We have fabricated ITO-ZnO composition spread films to investigate the effects of substrate temperature on their electrical and optical properties by using combinatorial RF magnetron sputtering. It turned out by X-ray measurement that the film with zinc contents above 16.0 at% [Zn/(In+Zn+Sn)] showed amorphous phase regardless of substrate temperature. The amorphous ITO-ZnO film had lower resistivity than polycrystalline films. When the films were deposited at 250 deg. C, the minimum resistivity of 3.0x10{sup -4} OMEGA cm was obtained with the zinc contents of 16.0 at%. The indium content could be reduced as high as {approx}30 at% compared to that of ITO for the films having similar resistivity ({approx}10{sup -4} OMEGA cm). However, a drastic increase of resistivity was observed for the ITO-ZnO films deposited at 350 deg. C, having zinc contents below 15.2 at%. - Graphical abstract: The effects of substrate temperature on properties of ITO-ZnO films were investigated by using combinatorial RF magnetron sputtering. The amorphous ITO-ZnO film had lower resistivity than polycrystalline films. The minimum resistivity of 3.0x10{sup -4} OMEGA cm was obtained with the substrate temperature of 250 deg. C and the zinc contents of 16.0 at%. The electronic states of ITO-ZnO films were discussed with related to the formation of transparent amorphous oxide semiconductor (TAOS).

  13. Characterization of sprayed TiO2 on ITO substrates for solar cell applications.

    PubMed

    Arunachalam, A; Dhanapandian, S; Manoharan, C; Sridhar, R

    2015-10-01

    Titanium dioxide (TiO2) thin films had been deposited with various substrate temperatures by spray pyrolysis technique onto ITO substrates. All films exhibited polycrystalline nature with the preferred orientation along (101) plane. At the substrate temperature 450 °C, the film favored the formation of anatase phase. The higher substrate temperature (475 °C) favored the appearance of rutile structure. The SEM image of the film at substrate temperature (Ts=450 °C) showed high structural quality with the porous nature. The typical AFM image of TiO2 film deposited at the substrate temperature, 450 °C depicted the regular arrangement of fine closely packed tetragonal structured grains. The transmittance of the spectra exhibited above 85% with energy band gap of 3.6 eV. From the study of photoluminescence, the emission at 417 nm, 437 nm and with weak emission at 551 nm was observed, which confirmed the lesser defects in the samples. The electrical resistivity was found to be 6.856×10(1) Ω cm for the substrate temperature 450 °C. The efficiency of anatase TiO2 photoelectrode deposited at the substrate temperature 450 °C based cell was much higher than the efficiency of TiO2 photoelectrode deposited at the substrate temperature 475 °C based cell. PMID:26004100

  14. Improved patterning of ITO coated with gold masking layer on glass substrate using nanosecond fiber laser and etching

    NASA Astrophysics Data System (ADS)

    Tan, Nguyen Ngoc; Hung, Duong Thanh; Anh, Vo Tran; BongChul, Kang; HyunChul, Kim

    2015-05-01

    In this paper, an indium-tin oxide (ITO) thin-film patterning method for higher pattern quality and productivity compared to the short-pulsed laser direct writing method is presented. We sputtered a thin ITO layer on a glass substrate, and then, plated a thin gold layer onto the ITO layer. The combined structure of the three layers (glass-ITO-gold) was patterned using laser-induced plasma generated by an ytterbium pulsed fiber laser (λ = 1064 nm). The results showed that the process parameters of 50 mm/s in scanning speed, 14 ns pulse duration, and a repetition rate of 7.5 kHz represented optimum conditions for the fabrication of ITO channels. Under these conditions, a channel 23.4 μm wide and 20 nm deep was obtained. However, built-up spikes (∼15 nm in height) resulted in a decrease in channel quality, and consequently, short circuit occurred at some patterned positions. These built-up spikes were completely removed by dipping the ITO layer into an etchant (18 wt.% HCl). A gold masking layer on the ITO surface was found to increase the channel surface quality without any decrease in ITO thickness. Moreover, the effects of repetition rate, scanning speed, and etching characteristics on surface quality were investigated.

  15. Laser scribing of indium tin oxide (ITO) thin films deposited on various substrates for touch panels

    NASA Astrophysics Data System (ADS)

    Tseng, Shih-Feng; Hsiao, Wen-Tse; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei; Chou, Chang-Pin

    2010-12-01

    In this study, a Nd:YAG laser with wavelength of 1064 nm is used to scribe the indium tin oxide (ITO) thin films coated on three types of substrate materials, i.e. soda-lime glass, polycarbonate (PC), and cyclic-olefin-copolymer (COC) materials with thickness of 20 nm, 30 nm, and 20 nm, respectively. The effect of exposure time adjusted from 10 μs to 100 μs on the ablated mark width, depth, and electrical properties of the scribed film was investigated. The maximum laser power of 2.2 W was used to scribe these thin films. In addition, the surface morphology, surface reaction, surface roughness, optical properties, and electrical conductivity properties were measured by a scanning electron microscope, a three-dimensional confocal laser scanning microscope, an atomic force microscope, and a four-point probe. The measured results of surface morphology show that the residual ITO layer was produced on the scribed path with the laser exposure time at 10 μs and 20 μs. The better edge qualities of the scribed lines can be obtained when the exposure time extends from 30 μs to 60 μs. When the laser exposure time is longer than 60 μs, the partially burned areas of the scribed thin films on PC and COC substrates are observed. Moreover, the isolated line width and resistivity values increase when the laser exposure time increases.

  16. Comparative study on the thickness-dependent properties of ITO and GZO thin films grown on glass and PET substrates

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Park, J.-K.; Baik, Y. J.; Kim, W. M.; Jeong, J.; Seong, T.-Y.

    2012-11-01

    The thickness-dependent properties of amorphous Sn-doped In2O3 (ITO) and polycrystalline Ga-doped ZnO (GZO) films grown on polyethylene terephthalate (PET) with a polymeric hard coating were compared with those deposited on Corning glass. The film thickness varied from 20 to 1310 nm. The electrical properties of the ITO films on PET were almost similar to those of the ITO films on glass. On the other hand, GZO films showed slightly poorer electrical properties when deposited on PET, but the difference was marginal. The electrical properties of amorphous ITO films were independent of film thickness, but polycrystalline GZO films exhibited monotonicallyimproving behavior with increasing thickness, mainly due to enhanced crystallinity and increased grain size with increasing film thickness. Although the air-referenced transmittance spectra of films on PET were about 2-3% lower than those on glass due to the lower transmittance of PET, the substrate-referenced optical transmittances of films on PET were higher than those on glass, reflecting the somewhat coarse structure of films on PET. Both the ITO and the GZO films on PET with a polymeric hard coating were shown to yield properties comparable to those oof both films on glass.

  17. Surface Modification of Nanocellulose Substrates

    NASA Astrophysics Data System (ADS)

    Zoppe, Justin Orazio

    Cellulose fibers constitute an important renewable raw material that is utilized in many commercial applications in non-food, paper, textiles and composite materials. Chemical functionalization is an important approach for improving the properties of cellulose based materials. Different approaches are used to graft polymeric chains onto cellulose substrates, which can be classified by two principal routes, namely 'grafting onto' or 'grafting from' methods. Never-dried cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with various macromolecules. In addition, the use of cellulose nanocrystals to reinforce poly(epsilon-caprolactone) (PCL) nanofibers was studied. Chemical grafting with low molecular weight polycaprolactone diol onto cellulose nanocrystals was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Significant improvements in the mechanical properties of the nanofibers after reinforcement with unmodified cellulose nanocrystals were confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNCs showed ca. 1.5-fold increase in Young's modulus and ultimate strength compared to PCL webs. The CNCs were also grafted with poly(N-isopropylacrylamide) (poly(NiPAAm)) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SETLRP) under various conditions at room temperature. The grafting process depended on the initiator and/or monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. In addition, the colloidal stability and thermo

  18. Highly conductive PEDOT:PSS on flexible substrate as ITO-free anode for polymer solar cells

    SciTech Connect

    Del Mauro, A. De Girolamo; Ricciardi, R.; Montanino, M.; Morvillo, P.; Minarini, C.

    2014-05-15

    In this work, highly conductive anode based on PEDOT:PSS is proposed as substitute of Indio-Tin Oxide (ITO) in flexible solar cells. The anodic conductive polymer was spin coated on a 125 μm thick polyethylene naphthalate (PEN) substrate. The obtained film was characterized in terms of structure and physical- chemical proprieties. The obtained results are very promising and the conductive film will be investigated in future as electrode in a complete polymeric solar cell.

  19. Synthesis and Analysis of MnTiO3 Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Martin, Emerick; Sahiner, Mehmet-Alper

    Perovskites like Manganese Titanium Oxide have interesting chemical properties that may be advantageous to the development of p-n junction photovoltaic cells. Due to the limited understanding behind the compound, it is essential to know the characteristics of it when it is deposited in thin film form. The cells were created using pulsed laser deposition method for two separate mediums (first layers after ITO). ZnO was deposited onto ITO glass for the first sample. For the second sample, a layer of pure Molybdenum was deposited onto the ITO glass. The MnTiO3 was then deposited onto both samples. There was a target thickness of 1000 Angstroms, but ellipsometry shows that, for the Mo based sample, that film thickness was around 1500 Angstroms. There were inconclusive results for the ZnO based sample. The concentration of active carriers was measured using a Hall Effect apparatus for the Mo based sample. The XRD analyses were used to confirm the perovskite structure of the films. Measurements for photoelectric conversion efficiency were taken using a Keathley 2602 ScourceMeter indicated low values for efficiency. The structural information that is correlated with the low electrical performance of this sample will be discussed. SHU-NJSGC Summer 2015 Fellowship.

  20. Optoelectronic properties and interfacial durability of CNT and ITO on boro-silicate glass and PET substrates with nano- and heterostructural aspects

    NASA Astrophysics Data System (ADS)

    Park, Joung-Man; Wang, Zuo-Jia; Kwon, Dong-Jun; DeVries, Lawrence

    2011-02-01

    Nano- and hetero-structures of carbon nanotube (CNT) and indium tin oxide (ITO) can control significantly piezoelectric and optoelectronic properties in Microelectromechanical Systems (MEMS) as sensing and actuator under cyclic loading. Optimized preparing conditions were obtained for multi-functional purpose of the specimen by obtaining the best dispersion and turbidity in the solution. Optical transmittance and electrical properties were investigated for CNT and ITO dipping and spraying coating on boro-silicate glass and polyethylene terephthalate (PET) substrates by electrical resistance measurement under cyclic loading and wettability test. Uniform dip-coating was performed using Wilhelmy plate method due to its simple and convenience. Spraying coating was applied to the specimen additionally. The change in the electrical resistance and optical properties of coated layer were mainly dependent upon the number of dip-coating, the concentration of CNT and ITO solutions, and the surface treatment condition. Electric properties of coating layers were measured using four-point probe method, and surface resistance was calculated using a dual configuration method. Optical transmittance of CNT and ITO coated PET film was also evaluated using UV spectrum. Surface energy and their hydrophilic and hydrophobic properties of CNT and ITO coated substrates were investigated by wettability test via static and dynamic contact angle measurements. As the elapsing time of cyclic loading passed, the stability of surface resistance and thus comparative interfacial adhesion between coated layer and substrates was evaluated to compare the thermodynamic work of adhesion, Wa. As dip-coating number increased, surface resistance of coated CNT decreased, whereas the transmittance decreased step-by-step due to the thicker CNT and ITO networked layer. Nano- and heterostructural effects of CNT and ITO solution on the optical and electrical effects have been studied continuously.

  1. Fabrication of hetero-junction diode using NiO thin film on ITO/glass substrate

    NASA Astrophysics Data System (ADS)

    Soni, Sonali; Sharma, Vinay; Kuanr, Bijoy K.

    2016-05-01

    Fabrication, characterization and testing of hetero-junctions of NiO thin films were done. Nickel films were evaporated on polished ITO coated glass substrates using thermal deposition. The films were annealed at high temperatures in the presence of oxygen to obtain NiO films. The rectifying current-voltage (I-V) properties confirmed that a hetero-junction diode was successfully formed. The AC and DC behavior of hetero-junction using DC silver-probes were determined. The threshold voltage, ideality factor and reverse saturation current of hetero junction were determined. We have compared these I-V characteristics with semiconducting PN junction diode. To test the device characteristics, we used the structure as a diode clipper at various frequencies. It is showed that our device is a better high-frequency junction-device than a normal PN junction diode.

  2. Substrate biasing effect on the physical properties of reactive RF-magnetron-sputtered aluminum oxide dielectric films on ITO glasses.

    PubMed

    Liang, Ling Yan; Cao, Hong Tao; Liu, Quan; Jiang, Ke Min; Liu, Zhi Min; Zhuge, Fei; Deng, Fu Ling

    2014-02-26

    High dielectric constant (high-k) Al2O3 thin films were prepared on ITO glasses by reactive RF-magnetron sputtering at room temperature. The effect of substrate bias on the subband structural, morphological, electrode/Al2O3 interfacial and electrical properties of the Al2O3 films is systematically investigated. An optical method based on spectroscopic ellipsometry measurement and modeling is adopted to probe the subband electronic structure, which facilitates us to vividly understand the band-tail and deep-level (4.8-5.0 eV above the valence band maximum) trap states. Well-selected substrate biases can suppress both the trap states due to promoted migration of sputtered particles, which optimizes the leakage current density, breakdown strength, and quadratic voltage coefficient of capacitance. Moreover, high porosity in the unbiased Al2O3 film is considered to induce the absorption of atmospheric moisture and the consequent occurrence of electrolysis reactions at electrode/Al2O3 interface, as a result ruining the electrical properties. PMID:24490685

  3. Evaluation of the single yeast cell's adhesion to ITO substrates with various surface energies via ESEM nanorobotic manipulation system.

    PubMed

    Shen, Yajing; Ahmad, Mohd Ridzuan; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Fukuda, Toshio

    2011-12-01

    Cell-surface adhesion force is important for cell activities and the development of bio materials. In this paper, a method for in situ single cell (W303) adhesion force measurement was proposed based on nanorobotic manipulation system inside an environment scanning electron microscope (ESEM). An end effector was fabricated from a commercial atomic force microscope (AFM) cantilever by focused ion beam (FIB) etching. The spring constant of it was calibrated by nanomanipulation approach. Three kinds of hydrophilic and hydrophobic ITO plates were prepared by using VUV-irradiation and OTS coating techniques. The shear adhesion strength of the single yeast cell to each substrate was measured based on the deflection of the end effector. The results demonstrated that the cell adhesion force was larger under the wet condition in the ESEM environment than in the aqueous condition. It also showed that the cell adhesion force to hydrophilic surface was larger than that to the hydrophobic surface. Studies of single cell's adhesion on various plate surfaces and environments could give new insights into the tissue engineering and biological field. PMID:22249767

  4. Electrical Properties Analysis of Copper doped CdTe/CdS Deposited Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Lesinski, Darren; Flaherty, James; Sahiner, M. Alper

    CdTe proves to be a viable source for renewable energy in the form of photovoltaic conversion. While CdTe/CdS naturally provide interesting results adding dopants to the cell can yield higher conversion efficiencies. Copper, famous for its electrical properties, can be used as a dopant in the CdTe layer. In conjunction with its dopant characteristics Copper also improves cell performance by acting as a low resistant and high current back contact. All thin films were synthesized using pulsed laser deposition onto ITO coated glass substrates. The CdS layer across all cells has an approximate thickness of 1500 Angstroms. The following CdTe layer has an approximate thickness of 5500 Angstroms. This created the base cell that was then doped. Cu, typically deposited using sublimation or vapor deposition, was done by PLD as well. Two of the three base cells were treated with Cu using the same deposition parameters. The third cell also received a CdCl treatment on top of the Cu layer to understand the effect when the oxygen layer is deferred. Ellipsometer measurements were used to confirm layer thickness. XRD analysis was used to confirm the presence of Cu and the crystal structure of the thin films. A Hall Effect Measurement system was used to measure active charge carrier concentration introduced by dopant. Also, a Keithley sourcemeter was utilized to determine photovoltaic properties. Notable results discussed will be the effects of Copper dopant on the electrical properties of CdS/CdTe based solar cells.

  5. Inorganic Surface Modification of Nonwoven Polymeric Substrates

    NASA Astrophysics Data System (ADS)

    Halbur, Jonathan Chandler

    In this study, atomic layer deposition (ALD), a vapor phase inorganic thin film deposition technique, is used to modify the surface of a range of industrially relevant polymers to enhance surface properties or impart additional functionalities. Several unique demonstrations of polymer surface modification are presented including uniform nanomaterial photodeposition to the surface of nonowoven fabrics and the first application of photocatalytic thin film coated nonwovens for advanced filtration of heavy metals from solution. Recent advances in polymer synthesis and processing technologies have resulted in the production of novel polymer systems with unique chemistries and sub-micron scale dimensions. As a result, advanced fiber systems have received much attention for potential use in a wide range of industrially and medically important applications such as advanced and selective filtration, catalysis, flexible electronics, and tissue engineering. However, tailoring the surface properties of the polymer is still needed in order to realize the full range of advanced applications, which can be difficult given the high complexity and non-uniformity of nonwoven polymeric structures. Uniform and controllable inorganic surface modification of nonwovens allows the introduction or modification of many crucial polymer properties with a wide range of application methods.

  6. Controllable electrochemical synthesis of ZnO nanorod arrays on flexible ITO/PET substrate and their structural and optical properties

    NASA Astrophysics Data System (ADS)

    Ko, Yeong Hwan; Kim, Myung Sub; Yu, Jae Su

    2012-10-01

    The structural and optical properties of vertically aligned zinc oxide (ZnO) nanorod arrays (NRAs) which were grown on the flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrate (i.e., ITO/PET substrate) with a thin sputtered ZnO seed layer via the electrochemical deposition method were studied. By changing the applied voltage and zinc nitrate concentration, the height/width and density of ZnO NRAs were controlled, with investigation on their crystallinity and optical properties. To understand the effect of ZnO seed layer on the growth property of ZnO nanorods, they were also grown on ITO/PET without any seed layer. Under an applied cathodic voltage of -2 V and zinc nitrate concentration of 10 mM, the ZnO NRAs increased the total transmittance up to 88.7% in the visible wavelength region due to the antireflective property and their X-ray diffraction (0 0 2) peak intensity was largely enhanced. Additionally, the near band edge emission of ZnO was significantly enhanced in photoluminescence spectrum. The light scattering and surface wetting properties were also explored.

  7. Silver nanocluster films on ITO coated glass as novel substrates for the detection of molecules using Surface Enhanced Raman Scattering (SERS)

    NASA Astrophysics Data System (ADS)

    Botta, Raju; Upender, G.; Bansal, C.

    2015-02-01

    A novel surface enhanced Raman scattering (SERS) substrates were prepared by a nanocluster deposition system. Silver nanoclusters were deposited on the indium tin oxide (ITO) coated glass slides. These films were annealed at 300°C for two hours to obtain the required size distribution for the desirable optical properties. The surface morphology of the films was examined using filed emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The surface plasmon resonance (SPR) of the pre annealed and the annealed Ag deposited ITO coated glass substrates were measured using UV-Vis spectrophotometer. The SERS studies were carried out on these substrates with Methylene Blue (MB) as a test molecule with 10-4 to 10-8 M concentrations using 514.5 nm and 632.81 nm laser excitation wavelengths. The results show that Ag nanoclusters of average particle size of ~ 150 nm act as very good SERS substrates for the detection 10-6 M of MB. Both the electromagnetic (EM) and chemical enhancement could be contributed to the SERS signal enhancement of MB molecule.

  8. ITO/poly(aniline)/sol-gel glass: An optically transparent, pH-responsive substrate for supported lipid bilayers

    PubMed Central

    Al-Obeidi, Ahmed; Ge, Chenhao; Orosz, Kristina S.; Saavedra, S. Scott

    2014-01-01

    Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO) electrode overcoated with a a poly(aniline) (PANI) thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB). The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4–9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm2/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation, and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels. PMID:25328882

  9. Poly(aniline) nanowires in sol-gel coated ITO: A pH-responsive substrate for planar supported lipid bilayers

    PubMed Central

    Ge, Chenhao; Orosz, Kristina S.; Armstrong, Neal R.; Saavedra, S. Scott

    2011-01-01

    Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying, fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers. PMID:21707069

  10. Electrooptical properties and structural features of amorphous ITO

    SciTech Connect

    Amosova, L. P.

    2015-03-15

    Thin indium-tin oxide (ITO) films are deposited onto cold substrates by magnetron-assisted sputtering. The dependences of the structural, electrical, and optical properties of the films on the oxygen content in the atmosphere of sputtering and the growth rate are studied. It is shown that, if the substrate temperature is no higher than the ITO crystallization temperature and the conditions of growth deviate from the optimal relationship between the oxygen pressure and the growth rate, the resistance of the layers can be six or seven orders of magnitude higher than the resistance of conducting amorphous layers and reach hundreds of megaohms. At the same time, the optical properties of insulating layers in the visible spectral region are completely identical to the properties of the conducing amorphous modification. A conceptual model of defects responsible for the insulating properties of amorphous ITO is proposed.

  11. Structure, optical and electrical properties of Bi2VO5.5 films deposited on ITO/glass substrates by chemical solution method

    NASA Astrophysics Data System (ADS)

    Guo, Ming; Shen, Yude; Liu, Changxin; Yang, Pingxiong

    2011-02-01

    Bismuth vanadate (Bi2VO5.5) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrates by chemical solution method combined with a rapid thermal annealing process. The structure of the films was characterized with X-ray diffraction and atomic force microscopy. The Bi2VO5.5 films annealed at 600 °C showed a good match with the ITO coated glass substrates and had a desired perovskite structure with high (00l) preferred orientation. The spherical grains with a homogeneous distribution of high crystallinity and packing density were observed. Optical properties of the Bi2VO5.5 thin films were studied by Raman spectra and the lattice vibration modes of the films were obtained. A low frequency dielectric dispersion was observed in the films. Dielectric constant and loss was about 75 and 0.076 at 10kHz, respectively. The ac conductivity obeyed Jonscher's universal power law, which may be originated a possible hopping mechanism for Bi2VO5.5 thin films. The complex impedance traces revealed material dielectric dispersion nature and the presence of grain effects in the films.

  12. Growth of the [110] oriented TiO2 nanorods on ITO substrates by sputtering technique for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Meng, Lijian; Chen, Hong; Li, Can; Dos Santos, Manuel

    2014-09-01

    TiO2 films have been deposited on ITO substrates by dc reactive magnetron sputtering technique. It has been found that the sputtering pressure is a very important parameter for the structure of the deposited TiO2 films. When the pressure is lower than 1 Pa, the deposited film has a dense structure and shows a preferred orientation along the [101] direction. However, the nanorod structure has been obtained as the sputtering pressure is higher than 1 Pa. These nanorods structure TiO2 film shows a preferred orientation along the [110] direction. The phases of the deposited TiO2 films have been characterized by the x-ray diffraction and the Raman scattering measurements. All the films show an anatase phase and no other phase has been observed. The results of the SEM show that these TiO2 nanorods are perpendicular to the ITO substrate. The TEM measurement shows that the nanorods have a very rough surface. The dye-sensitized solar cells (DSSCs) have been assembled using these TiO2 nanorod films prepared at different sputtering pressures as photoelectrode. And the effect of the sputtering pressure on the properties of the photoelectric conversion of the DSSCs has been studied.

  13. SURFACE MODIFICATION OF ZIRCALOY-4 SUBSTRATES WITH NICKEL ZIRCONIUM INTERMETALLICS

    SciTech Connect

    Luscher, Walter G.; Gilbert, Edgar R.; Pitman, Stan G.; Love, Edward F.

    2013-02-01

    Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel-zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370°C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness.

  14. CuS p- type thin film characterization deposited on Ti, ITO and glass substrates using spray pyrolysis deposition (SPD) for light emitting diode (LED) application

    NASA Astrophysics Data System (ADS)

    Sabah, Fayroz A.; Ahmed, Naser M.; Hassan, Z.; Rasheed, Hiba S.; Azzez, Shrook A.; Al-Hazim, Nabeel Z.

    2016-07-01

    The copper sulphide (CuS) thin films were grown with good adhesion by spray pyrolysis deposition (SPD) on Ti, ITO and glass substrates at 200 °C. The distance between nozzle and substrate is 30 cm. The composition was prepared by mixing copper chloride CuCl2.2H2O as a source of Cu2+ and sodium thiosulfate Na2S2O3.5H2O as a source of and S2-. Two concentrations (0.2 and 0.4 M) were used for each CuCl2 and Na2S2O3 to be prepared and then sprayed (20 ml). The process was started by spraying the solution for 3 seconds and after 10 seconds the cycle was repeated until the solution was sprayed completely on the hot substrates. The structural characteristics were studied using X-ray diffraction; they showed covellite CuS hexagonal crystal structure for 0.2 M concentration, and covellite CuS hexagonal crystal structure with two small peaks of chalcocite Cu2S hexagonal crystal structure for 0.4 M concentration. Also the surface and electrical characteristics were investigated using Field Emission Scanning Electron Microscopy (FESEM) and current source device, respectively. The surface study for the CuS thin films showed nanorods to be established for 0.2 M concentration and mix of nanorods and nanoplates for 0.4 M concentration. The electrical study showed ohmic behavior and low resistivity for these films. Hall Effect was measured for these thin films, it showed that all samples of CuS are p- type thin films and ensured that the resistivity for thin films of 0.2 M concentration was lower than that of 0.4 M concentration; and for the two concentrations CuS thin film deposited on ITO had the lowest resistivity. This leads to the result that the conductivity was high for CuS thin film deposited on ITO substrate, and the conductivity of the three thin films of 0.2 M concentration was higher than that of 0.4 M concentration.

  15. Substrate Recognition and Modification by the Nosiheptide Resistance Methyltransferase

    PubMed Central

    Chen, Dongrong; Murchie, Alastair I. H.

    2015-01-01

    Background The proliferation of antibiotic resistant pathogens is an increasing threat to the general public. Resistance may be conferred by a number of mechanisms including covalent or mutational modification of the antibiotic binding site, covalent modification of the drug, or the over-expression of efflux pumps. The nosiheptide resistance methyltransferase (NHR) confers resistance to the thiazole antibiotic nosiheptide in the nosiheptide producer organism Streptomyces actuosus through 2ʹO-methylation of 23S rRNA at the nucleotide A1067. Although the crystal structures of NHR and the closely related thiostrepton-resistance methyltransferase (TSR) in complex with the cofactor S-Adenosyl-L-methionine (SAM) are available, the principles behind NHR substrate recognition and catalysis remain unclear. Methodology/Principal Findings We have analyzed the binding interactions between NHR and model 58 and 29 nucleotide substrate RNAs by gel electrophoresis mobility shift assays (EMSA) and fluorescence anisotropy. We show that the enzyme binds to RNA as a dimer. By constructing a hetero-dimer complex composed of one wild-type subunit and one inactive mutant NHR-R135A subunit, we show that only one functional subunit of the NHR homodimer is required for its enzymatic activity. Mutational analysis suggests that the interactions between neighbouring bases (G1068 and U1066) and A1067 have an important role in methyltransfer activity, such that the substitution of a deoxy sugar spacer (5ʹ) to the target nucleotide achieved near wild-type levels of methylation. A series of atomic substitutions at specific positions on the substrate adenine show that local base-base interactions between neighbouring bases are important for methylation. Conclusion/Significance Taken together these data suggest that local base-base interactions play an important role in aligning the substrate 2’ hydroxyl group of A1067 for methyl group transfer. Methylation of nucleic acids is playing an

  16. Improved efficiency and stability of flexible dye sensitized solar cells on ITO/PEN substrates using an ionic liquid electrolyte.

    PubMed

    Han, Yu; Pringle, Jennifer M; Cheng, Yi-Bing

    2015-01-01

    Flexible dye-sensitized solar cells (DSSCs) built on plastic substrates have attracted great interest as they are lightweight and can be roll-to-roll printed to accelerate production and reduce cost. However, plastic substrates such as PEN and PET are permeable to water, oxygen and volatile electrolyte solvents, which is detrimental to the cell stability. Therefore, to address this problem, in this work, an ionic liquid (IL) electrolyte is used to replace the volatile solvent electrolyte. The initial IL-based devices only achieved around 50% of the photovoltaic conversion efficiency of the cells using the solvent electrolyte. Current-voltage and electrochemical impedance spectroscopy (EIS) analysis of the cells in the dark indicated that this lower efficiency mainly originated from (i) a lack of blocking layer to reduce recombination, and (ii) a lower charge collection efficiency. To combat these problems, cells were developed using a 12 nm thick blocking layer, produced by atomic layer deposition, and 1 μm thick P25 TiO2 film sensitized with the hydrophobic MK-2 dye. These flexible DSSCs utilizing an IL electrolyte exhibit significantly improved efficiencies and a <10% drop in performance after 1000 h aging at 60°C under continuous light illumination. PMID:25476521

  17. Growth and physical properties of p-Zn x Cd1- x S thin films thermally evaporated on ITO-coated glass substrates

    NASA Astrophysics Data System (ADS)

    Yoon, Eun Jeong; Han, Dong Hun; Lee, Jeoung Ju; Lee, Jong Duk; Kang, Kwang Yong; Lee, Seung Hwan; Shewale, Prashant Shivaji

    2015-01-01

    Zn x Cd1- x S ( x = 0.15, 0.44, 0.62, 0.80, and 0.95) thin films of about 340 nm in thickness were deposited on indium-tin-oxide (ITO)-coated glass substrates by using thermal evaporation of high-purity ZnS and CdS mixed tablets in high vacuum. X-ray diffraction spectra showed that the Zn x Cd1- x S thin films were preferentially grown along the (111) orientation. The Zn x Cd1- x S crystal structure was a mixture structure of the ZnS and the CdS cubic zincblende structures with lattice constants a = 5.670 Å to a = 5.734 Å for CdS and a = 5.437 Å for ZnS. The ( αh ν)2 vs. h ν plots for the Zn x Cd1- x S thin films showed that all samples had direct transition band gaps. The energy band gaps of the Zn x Cd1- x S thin films increased monotonically from 2.45 eV for x = 0.15 to 3.37 eV for x = 0.95. The dynamical behavior of the charge carriers in the Zn x Cd1- x S thin films was investigated by using the photoinduced discharge characteristics (PIDC) technique.

  18. Thickness dependent optical properties of PEMA and (PEMA)0.85/(ZnO)0.15 nanocomposite films deposited by spray pyrolysis technique on ITO substrate

    NASA Astrophysics Data System (ADS)

    Thakur, Anjna; Thakur, Priya; Yadav, Kamlesh

    2016-05-01

    In this paper, poly (ethyl methacrylate) (PEMA) and (PEMA)0.85/(ZnO)0.15 nanocomposite films for 2, 3, 4 and 5 minutes have been deposited by spray pyrolysis technique on indium tin oxide (ITO) coated substrate. The effect of thickness of the film on the morphological and optical properties of PEMA and (PEMA)0.85/(ZnO)0.15 nanocomposite films are studied. The morphological and optical properties of pure PEMA and (PEMA)0.85/(ZnO)0.15 nanocomposite films are compared. The field emission scanning electron microscopy (FESEM) shows that as the thickness of film increases, uniformity of films increases. It is found from UV-Visible spectra that the energy band gap decreases with increasing the deposition time and refractive index increases with increasing the thickness of the film. The band gap of the nanocomposites is found less than the pure polymer film and opposite trend is observed for refractive index. The optical absorption of PEMA/ZnO nanocomposite films is higher than pure PEMA film. The thickness of the nanocomposite film plays a significant role in the tunability of the optical properties.

  19. Effects of annealing temperature on optical, morphological, and electrical characteristics of polyfluorene-derivative thin films on ITO glass substrate.

    PubMed

    Lim, Way Foong; Quah, Hock Jin; Hassan, Zainuriah

    2016-02-20

    The effects of postdeposition annealing temperature (125°C-200°C) toward optical, morphological, and electrical characteristics of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-phenylene)] end capped with dimethylphenyl group deposited on indium tin oxide glass substrates were investigated. Green and red-infrared photoluminescence emissions, originating from П-conjugation aggregates and keto-type defects did not attenuate the intensity of the blue emission peak. This suggested that the aggregates and defects might serve as local traps for radiative recombination. In samples annealed at 125°C-175°C, a decreasing optical energy gap (E(g)) that decreased barrier height as well as an increasing amount of traps have increased current conduction via thermionic emission and trap-assisted tunneling. Nonetheless, an acquisition of the largest E(g) and amount of traps testified that thermionic emission was dominating current conduction, surpassing trap-assisted tunneling in samples annealed at 200°C. PMID:26906569

  20. Molecular dynamics studies of thin film nucleation and substrate modification

    NASA Astrophysics Data System (ADS)

    Hu, Yanhong

    Deposition of energetic particles on solid surfaces has found increasing application in surface science. However, the detailed surface chemistry and relevant atomic mechanisms are not well understood. Molecular dynamics (MD) simulations are an ideal method to study these processes atomistically because they usually occur on short time scales (of the order of a few picoseconds). In this dissertation, MD simulations are performed to investigate thin film formation through organic cluster beam deposition and chemical modification of carbon nanotube/polymer composites via polyatomic ion beam deposition. The interatomic forces are calculated from the reactive empirical bond-order (REBO) potential for carbon-based systems coupled with the Lennard-Jones potentials. The reliability of this approach is examined by comparing its predictions for ethylene-cluster beam deposition with the results of a more accurate order-N nonorthogonal tight-binding method. The results show that the REBO potential captures the general characters of the relevant chemistry. The deposition processes of interest occur at room temperature; hence, appropriate temperature control methods must be employed in the simulations. A comparison study of four temperature control methods during the simulation of cluster deposition finds that the generalized Langevin equation approach is sufficient for dissipation of excess system energy if the deposition occurs on a large enough substrate at a moderate incident energy (<40 eV/cluster-atom). A new temperature control method has been developed for use at higher incident energies. In the simulations of thin film formation through organic cluster beam deposition, the dependence of the results on the intracluster bonding, incident angle and deposition direction is examined. Beams of ethylene clusters, adamantane molecules, and C20 molecules are thus deposited on a diamond surface with varying lateral momenta along two different crystallographic orientations at

  1. Studies on polyurethane adhesives and surface modification of hydrophobic substrates

    NASA Astrophysics Data System (ADS)

    Krishnamoorthy, Jayaraman

    studies involved making functionalized, thickness-controlled, wettability-controlled multilayers on hydrophobic substrates and the adsorption of carboxylic acid-terminated poly(styrene-b-isoprene) on alumina/silica substrates. Poly(vinyl alcohol) has been shown to adsorb onto hydrophobic surfaces irreversibly due to hydrophobic interactions. This thin semicrystalline coating is chemically modified using acid chlorides, butyl isocyanate and butanal to form thicker and hydrophobic coatings. The products of the modification reactions allow adsorption of a subsequent layer of poly(vinyl alcohol) that could subsequently be hydrophobized. This 2-step (adsorption/chemical modification) allows layer-by-layer deposition to prepare coatings with thickness, chemical structure and wettability control on any hydrophobic surface. Research on adsorption characteristics of carboxylic acid-terminated poly(styrene-b-isoprene) involved syntheses of block copolymers with the functional group present at specific ends. Comparative adsorption studies for carboxylic acid-terminated and hydrogen-terminated block copolymers was carried out on alumina and silica substrates.

  2. Sol-gel synthesis, characterization and optical properties of mercury-doped TiO 2 thin films deposited on ITO glass substrates

    NASA Astrophysics Data System (ADS)

    Mechiakh, R.; Ben Sedrine, N.; Chtourou, R.

    2011-08-01

    The Hg-doped and undoped nano-crystalline TiO 2 films on ITO glass substrates surface and polycrystalline powders were prepared by sol-gel dip coating technique. The crystal structure and surface morphology of TiO 2 were characterized by means of X-ray diffractometer (XRD), atomic force microscope (AFM), spectrophotometer, Fourier-transform infrared (FTIR), and spectroscopic ellipsometry (SE). The results indicated that the powder of TiO 2, doped with 5% Hg in room temperature was only composed of the anatase phase whereas in the undoped powder exhibits an amorphous phase were present. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature 400 °C. The average crystallite size of the undoped TiO 2 films was about 8.17 nm and was increased with Hg-doping in the TiO 2 films. Moreover, the grains distributed more uniform and the surface roughness was greater in the Hg-doped TiO 2 films than in the undoped one. Refractive index and porosity were calculated from the measured transmittance spectrum. The values of the index of refraction are in the range (1.95-2.49) and the porosity is in the range (47-2.8). The coefficient of transmission varies from 60 to 90%. SE study was used to determine the annealing temperature effect on the optical properties in the wavelength range from 0.25 to 2 μm and the optical gap of the Hg-doped TiO 2 thin films.

  3. Characteristics of indium-tin-oxide (ITO) nanoparticle ink-coated layers recycled from ITO scraps

    NASA Astrophysics Data System (ADS)

    Cha, Seung-Jae; Hong, Sung-Jei; Lee, Jae Yong

    2015-09-01

    This study investigates the characteristics of an indium-tin-oxide (ITO) ink layer that includes nanoparticles synthesized from ITO target scraps. The particle size of the ITO nanoparticle was less than 15 nm, and the crystal structure was cubic with a (222) preferred orientation. Also, the composition ratio of In to Sn was 92.7 to 7.3 in weight. The ITO nanoparticles were well dispersed in the ink solvent to formulate a 20-wt% ITO nanoparticle ink. Furthermore, the ITO nanoparticle ink was coated onto a glass substrate, followed by heat-treatment at 600 °C. The layer showed good sheet resistances below 400 Ω/□ and optical transmittances higher than 88% at 550 nm. Thus, we can conclude that the characteristics of the layer make it highly applicable to a transparent conductive electrode.

  4. Pulsed laser deposition of ITO thin films and their characteristics

    SciTech Connect

    Zuev, D. A. Lotin, A. A.; Novodvorsky, O. A.; Lebedev, F. V.; Khramova, O. D.; Petuhov, I. A.; Putilin, Ph. N.; Shatohin, A. N.; Rumyanzeva, M. N.; Gaskov, A. M.

    2012-03-15

    The indium tin oxide (ITO) thin films are grown on quartz glass substrates by the pulsed laser deposition method. The structural, electrical, and optical properties of ITO films are studied as a function of the substrate temperature, the oxygen pressure in the vacuum chamber, and the Sn concentration in the target. The transmittance of grown ITO films in the visible spectral region exceeds 85%. The minimum value of resistivity 1.79 Multiplication-Sign 10{sup -4} {Omega} cm has been achieved in the ITO films with content of Sn 5 at %.

  5. Modification of polymeric substrates using surface-grafted nanoscaffolds

    NASA Astrophysics Data System (ADS)

    Thompson, Kimberlee Fay

    Surface grafting and modification of poly(acrylic acid) (PAA) were performed on nylon 6,6 carpet fibers to achieve permanent stain and soil resistance. PAA was grafted to nylon and modified with 1H, 1H-pentadecafluorooctyl amine (PDFOA) using an amidation agent, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM). The first goal was to optimize acrylamide modification of PAA in solution. Aqueous reactions with taurine, hydroxyethyl amine, and butyl amine progressed ˜100%, while PDFOA reactions in MeOH progressed ˜80%. Reaction products precipitated at 77% butyl or 52% PDFOA acrylamide contents. The second goal was to optimize the PAA grafting process. First, PAA was adsorbed onto nylon 6,6 films. Next, DMTMM initiated grafting of adsorbed PAA. PAA surface coverage was ˜78%, determined by contact angle analysis of the top 0.1--1 nm and x-ray photoelectron spectroscopy (XPS) analysis of the top 3--10 nm. The third goal was to modify PAA grafted nylon films with butyl amine and PDFOA. Randomly methylated beta-cyclodextrin (RAMEB) solubilized PDFOA in water. Contact angle detected ˜100% surface reaction for each amine, while XPS detected ˜77% butyl amine (H2O) and ˜50% for PDFOA (MeOH or H2O pH = 7) reactions. In H2O pH = 12, the PDFOA reaction progressed ˜89%, perhaps due to greater efficiency, access and solubility. The fourth goal was to perform surface depth profiling via angle-resolved XPS analysis (ARXPS). The PAA surface coverage from contact angle and XPS was confirmed. Further, adsorbed PAA was thicker than grafted PAA, supporting the theory that PAA adsorption occurs in thick layers onto nylon followed by DMTMM-activated spreading and grafting of thinner PAA layers across the surface. The PDFOA reaction in McOH produced a highly fluorinated but thin exterior and an unreacted PAA interior. The PDFOA reaction in H 2O pH = 12 produced a completely fluorinated exterior and highly fluorinated interior. Thus surface modification levels

  6. Surface Modification of Polymer Substrates by Oxygen Ion Irradiation

    SciTech Connect

    Takaoka, G. H.; Ryuto, H.; Araki, R.; Yakushiji, T.

    2008-11-03

    Oxygen cluster ions and/or monomer ions were used for the sputtering and the surface modification of polymers such as polycarbonate (PC) and polyethylene terephthalate (PET). For the case of oxygen cluster ion irradiation, the sputtered depth increased with increase of the acceleration voltage, and the sputtering yield was much larger than that by the monomer ion irradiation. The sputtered particles represented the polymer structure, which indicated that the bond scission by the cluster ion irradiation resulted in an ejection of monomer molecule through the intermolecular collision. On the other hand, for the oxygen monomer ion irradiation, the implanted depth increased with increase of the acceleration voltage, and the bond scission occurred at the deep region through the binary collision with the high energetic ions. Therefore, the sputtering yield for the polymer surfaces decreased, and the sputtering effect became very small. Furthermore, the simultaneous use of oxygen cluster and monomer ions was more effective for oxidation of the PET surfaces rather than the monomer ion irradiation or the cluster ion irradiation. As a result, the contact angle measurement showed that the wettability of the PET surfaces irradiated by the simultaneous use of oxygen cluster and monomer ions was much enhanced.

  7. Patterning of ITO with picosecond lasers

    NASA Astrophysics Data System (ADS)

    Račiukaitis, Gediminas; Brikas, Marijus; Gedvilas, Mindaugas; Darčianovas, Gediminas

    2007-02-01

    Indium-tin oxide (ITO) is the main material for making transparent electrodes in electronic devices and flat panel displays. Laser-direct-write technology has been widely used for patterning ITO. The well defined edges and good electrical isolation at a short separation are required for the modern OLED and RFID devices of high packing density. High repetition rate lasers with a short, picosecond pulse width offer new possibilities for high efficiency structuring of transparent conductors on glass and other substrates. The results of patterning the ITO film on glass with picosecond lasers at various wavelengths are presented. Laser radiation initiated ablation of the material, forming trenches in ITO. Profile of the trenches was analyzed with a phase contrast optical microscope, a stylus type profiler, SEM and AFM. Clean removal of the ITO layer was achieved with the 266 nm radiation when laser fluence was above the threshold at 0.20 J/cm2, while for the 355 nm radiation the threshold was higher, above 0.46 J/cm2. The glass substrate was damaged in the area where the fluence was higher than 1.55 J/cm2. The 532 nm radiation allowed getting well defined trenches, but a lot of residues in the form of dust were generated on the surface. UV radiation at the 266 nm provided the widest working window for ITO ablation without damage of the substrate. Use of UV laser radiation with fluences close to the ablation threshold made it possible to minimize surface contamination and the recast ridge formation during the process.

  8. Substrate and head group modifications for enhanced stability in molecular electronic devices

    NASA Astrophysics Data System (ADS)

    Ferrato, Michael-Anthony

    Poor Self-Assembled Monolayer (SAM) stability is a barrier which impedes the incorporation of molecular layers as functional components in electronic device architectures. Here we investigate the molecular electronic characteristics of two well established approaches to enhancing SAM stability. In Chapter 2 we investigate the electrochemical modification of Au substrates by the underpotential deposition of silver monolayers (AgUPD). In Chapter 3 we study chelating dithiophosphinic acid (DTPA) head groups to anchor SAM molecules to substrates. Based on molecular electronic characterization using EGaIn Tip testbeds, we observed that AgUPD substrates maintained the inherent electronic character of n-alkanethiolate SAMs, but reduced charge transport by almost 1 order of magnitude as compared with the same SAMs on bulk Au substrates. Similar molecular electronic characterization of (diphenyl)dithiophosphinic acid SAMs on Au substrates revealed that the DTPA head group induced a ~3 order of magnitude drop in charge transport as compared with analogous thiophenol SAMs.

  9. Effects of different substrate surface modifications on the epitaxial ZnO/Si

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Jin, Changlian; Zhan, Huahan; Chen, Xiaohang; Xu, Fuchun; Zhou, Yinghui; Wang, Huiqiong; Kang, Junyong

    2013-09-01

    To produce high quality ZnO/Si for the applications in short wavelength optoelectronic devices, the effects of different silicon surface modifications on the overgrown ZnO thin film were investigated. Samples were grown by a plasma assistant molecular beam epitaxy at room temperature, avoiding the oxidation of the Si surface and the thermal stress caused by difference of the thermal expansion coefficients between ZnO and silicon. Different modifications on the Si(100) substrate surface including nitridation, oxidation, and depositions of Mg and Zn, were employed. The effects on the overgrown ZnO layers and the interlayer SiOx were investigated by atomic force microscopy, photoluminescence, X-ray diffraction and auger depth electron spectroscopy. All the modifications were effective in different degrees at reducing the SiOx amorphous layer. However, different mechanisms resulted in distinct performance in crystal structure and optical property.

  10. Enhanced photoluminescence in Au-embedded ITO nanowires.

    PubMed

    Kim, Hyunsu; Park, Sunghoon; Jin, Changhyun; Lee, Chongmu

    2011-12-01

    Gold (Au)-embedded indium tin oxide (ITO) nanowires were synthesized by thermal evaporation of a mixture of In(2)O(3,) SnO(2) and graphite powders on Si (100) substrates coated with Au thin films followed by annealing. At the initial stages of annealing, Au formed a continuous linear core located along the long axis of each ITO nanowire. The morphology of the Au core changed from a continuous line to a discrete line, and then to a droplet-like chain, finally evolving into a peapod in which crystalline Au nanoparticles were encapsulated in crystalline ITO with increasing annealing temperature. The ITO nanowires with the Au core showed an emission band at ~380 nm in the ultraviolet region. The ultraviolet emission intensity increased rapidly with increasing annealing temperature. The intensity of emission from the Au-peapod ITO nanowires (annealed at 750 °C) was approximately 20 times higher than that of the emission from the Au-core/ITO-shell ITO nanowires with a continuous linear shaped-Au core (annealed at 550 °C). This ultraintense ultraviolet emission might have originated mainly from the enhanced crystalline quality of the annealed ITO nanowires. PMID:22087582

  11. Electrochemical characterization of organosilane-functionalized nanostructured ITO surfaces

    NASA Astrophysics Data System (ADS)

    Pruna, R.; Palacio, F.; López, M.; Pérez, J.; Mir, M.; Blázquez, O.; Hernández, S.; Garrido, B.

    2016-08-01

    The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis of redox active molecules. ITO films were fabricated by using electron beam evaporation at different substrate temperatures and subsequently annealed for promoting their crystallization. The morphology of the deposited material was monitored by scanning electron microscopy, confirming the deposition of either thin films or nanowires, depending on the substrate temperature. Electrochemical surface characterization revealed a 45 % increase in the electroactive surface area of nanostructured ITO with respect to thin films, one third lower than the geometrical surface area variation determined by atomic force microscopy. ITO surfaces were functionalized with a model organic molecule known as 6-(ferrocenyl)hexanethiol. The chemical attachment was done by means of a glycidoxy compound containing a reactive epoxy group, the so-called 3-glycidoxypropyltrimethoxy-silane. ITO functionalization was useful for determining the benefits of nanostructuration on the surface coverage of active molecules. Compared to ITO thin films, an increase in the total peak height of 140 % was observed for as-deposited nanostructured electrodes, whereas the same measurement for annealed electrodes resulted in an increase of more than 400 %. These preliminary results demonstrate the ability of nanostructured ITO to increase the surface-to-volume ratio, conductivity and surface area functionalization, features that highly benefit the performance of biosensors.

  12. Fabrication and selective surface modification of 3-dimensionally textured biomedical polymers from etched silicon substrates.

    PubMed

    Kapur, R; Spargo, B J; Chen, M S; Calvert, J M; Rudolph, A S

    1996-01-01

    A new method is described for producing biomedically relevant polymers with precisely defined micron scale surface texture in the x, y, and z planes. Patterned Si templates were fabricated using photolithography to create a relief pattern in photoresist with lateral dimensions as small as 1 micron. Electroless Ni was selectively deposited in the trenches of the patterned substrate. The Ni served as a resilient mask for transferring the patterns onto the Si substrate to depths of up to 8.5 microns by anisotropic reactive ion etching with a fluorine-based plasma. The 3-dimensional (3-D) textured silicon substrates were used as robust, reusable molds for pattern transfer onto poly (dimethyl siloxane), low density poly (ethylene), poly (L-lactide), and poly (glycolide) by either casting or injection molding. The fidelity of the pattern transfer from the silicon substrates to the polymers was 90 to 95% in all three planes for all polymers for more than 60 transfers from a single wafer, as determined by scanning electron microscopy and atomic force microscopy. Further, the 3-D textured polymers were selectively modified to coat proteins either in the trenches or on the mesas by capillary modification or selective coating techniques. These selectively patterned 3-D polymer substrates may be useful for a variety of biomaterial applications. PMID:8953387

  13. Surface modification of several dental substrates by non-thermal, atmospheric plasma brush

    PubMed Central

    Chen, Mingsheng; Zhang, Ying; Driver, M. Sky; Caruso, Anthony N.; Yu, Qingsong; Wang, Yong

    2013-01-01

    Objective The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of four dental substrates. Methods Specimens of dental substrates including dentin, enamel, and two composites Filtek Z250, Filtek LS Silorane were prepared (~2 mm thick, ~10 mm diameter). The prepared surfaces were treated for 5–45 s with a non-thermal atmospheric plasma brush working at temperatures from 36 to 38 °C. The plasma-treatment effects on these surfaces were studied with contact-angle measurement, X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM). Results The non-thermal atmospheric argon plasma brush was very efficient in improving the surface hydrophilicity of four substrates studied. The results indicated that water contact angle values decreased considerably after only 5 s plasma treatment of all these substrates. After 30 s treatment, the values were further reduced to <5°, which was close to a value for super hydrophilic surfaces. XPS analysis indicated that the percent of elements associated with mineral in dentin/enamel or fillers in the composites increased. In addition, the percent of carbon (%C) decreased while %O increased for all four substrates. As a result, the O/C ratio increased dramatically, suggesting that new oxygen-containing polar moieties were formed on the surfaces after plasma treatment. SEM surface images indicated that no significant morphology change was induced on these dental substrates after exposure to plasmas. Significance Without affecting the bulk properties, a super-hydrophilic surface could be easily achieved by the plasma brush treatment regardless of original hydrophilicity/hydrophobicity of dental substrates tested. PMID:23755823

  14. Thermally induced modifications of the optic properties of lead zirconate titanate thin films obtained on different substrates by sol-gel synthesis

    SciTech Connect

    D'Elia, Stefano; Castriota, Marco; Scaramuzza, Nicola; Versace, Carlo; Cazzanelli, Enzo; Vena, Carlo; Strangi, Giuseppe; Bartolino, Roberto; Policicchio, Alfonso; Agostino, Raffaele Giuseppe

    2008-12-15

    Lead zirconium titanate PbZr{sub 0.53}Ti{sub 0.47}O{sub 3} (PZT) thin films have been obtained by sol-gel synthesis, deposited on different substrates [float glass, indium tin oxide (ITO)-coated float glass, and intrinsic silicon wafer], and later subjected to different thermal treatments. The morphologic and the structural properties of both PZT thin films and substrates have been investigated by scanning electron microscope and their composition was determined by energy dispersive x-ray (EDX) analysis. Moreover, variable angle spectroscopic ellipsometry provides relevant information on the electronic and optical properties of the samples. In particular, the optical constant dispersion of PZT deposited on ITO-coated float glasses shows a small absorption resonance in the near IR region, not observed in PZT films deposited on the other substrates, so that such absorption resonance can be explained by interfacial effects between ITO and PZT layers. This hypothesis is also supported by EDX measurements, showing an interdiffusion of lead and indium ions, across the PZT-ITO interface, that can generate a peculiar charge distribution in this region.

  15. Dependence of light outcoupling in organic light-emitting devices on ITO thickness and roughness

    NASA Astrophysics Data System (ADS)

    Zhang, Yingjie; Aziz, Hany

    2015-09-01

    The efficiency of organic light-emitting devices (OLEDs) is shown to significantly depend on both the thickness and roughness of the indium tin oxide (ITO) anode. The effects of changing the ITO thickness from 45 nm to 130 nm are found to be able to vary the current efficiency by 40%. The underlying mechanism is studied and revealed to be related to microcavity effects. The transmittance of the ITO substrate changes significantly with the ITO thickness, resulting in variations in microcavity, and thus light outcoupling efficiency. On the other hand, the effects of increasing the ITO roughness (rms) from 3.3 nm to 8.5 nm are found to increase light scattering at the ITO/organic interface, thus improving extraction of light trapped in the organic/ITO wave-guided mode. In addition to the enhancement in current efficiency, the device fabricated on rough ITO shows similar driving voltage to that made on smooth ITO, indicating that charge balance is not altered by ITO roughness. Contrary to common belief in the community, the lifetime of the OLED is not affected when using rough ITO. The results demonstrate the significant efficiency benefits of using ITO with optimal thicknesses and higher roughness in OLEDs.

  16. ZnO nanostructures directly grown on paper and bacterial cellulose substrates without any surface modification layer.

    PubMed

    Costa, Saionara V; Gonçalves, Agnaldo S; Zaguete, Maria A; Mazon, Talita; Nogueira, Ana F

    2013-09-21

    In this report, hierarchical ZnO nano- and microstructures were directly grown for the first time on a bacterial cellulose substrate and on two additional different papers by hydrothermal synthesis without any surface modification layer. Compactness and smoothness of the substrates are two important parameters that allow the growth of oriented structures. PMID:23912253

  17. Enhancing the Properties of Carbon and Gold Substrates by Surface Modification

    SciTech Connect

    Jennifer Anne Harnisch

    2002-06-27

    The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol (BHT) SAMs. BHT chemisorbs to the gold surface in a previously unprecedented planar fashion. Carbon and gold substrates can be chemically altered by several methodologies resulting in new surface properties. The development of modification protocols and their application in the analytical arena is considered herein.

  18. Catheter ablation of persistent atrial fibrillation: The importance of substrate modification

    PubMed Central

    Letsas, Konstantinos P; Efremidis, Michael; Sgouros, Nikolaos P; Vlachos, Konstantinos; Asvestas, Dimitrios; Sideris, Antonios

    2015-01-01

    Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively “healthy islands” within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes. PMID:25810810

  19. N-terminal modifications of cellular proteins: The enzymes involved, their substrate specificities and biological effects

    PubMed Central

    Varland, Sylvia; Osberg, Camilla; Arnesen, Thomas

    2015-01-01

    The vast majority of eukaryotic proteins are N-terminally modified by one or more processing enzymes. Enzymes acting on the very first amino acid of a polypeptide include different peptidases, transferases, and ligases. Methionine aminopeptidases excise the initiator methionine leaving the nascent polypeptide with a newly exposed amino acid that may be further modified. N-terminal acetyl-, methyl-, myristoyl-, and palmitoyltransferases may attach an acetyl, methyl, myristoyl, or palmitoyl group, respectively, to the α-amino group of the target protein N-terminus. With the action of ubiquitin ligases, one or several ubiquitin molecules are transferred, and hence, constitute the N-terminal modification. Modifications at protein N-termini represent an important contribution to proteomic diversity and complexity, and are essential for protein regulation and cellular signaling. Consequently, dysregulation of the N-terminal modifying enzymes is implicated in human diseases. We here review the different protein N-terminal modifications occurring co- or post-translationally with emphasis on the responsible enzymes and their substrate specificities. PMID:25914051

  20. Laser induced modification of mechanical properties of nanostructures: graphene–water adsorbate–substrate

    NASA Astrophysics Data System (ADS)

    Pivovarov, P. A.; Frolov, V. D.; Zavedeev, E. V.; Khomich, A. A.; Konov, V. I.

    2016-08-01

    The possibility of laser induced modification of local mechanical properties of polycrystalline chemical vapor deposition graphene on silicon substrate in air has been demonstrated. Nanosecond laser pulses (wavelength 532 nm) with focal spot diameter ~1 μm were used. Samples were placed and irradiated inside a scanning probe microscope (SPM) that allowed in situ studies of surface morphology and mechanical phase contrast in SPM tapping mode before and after multipulsed laser treatment. It was found that along with local profile transformation of graphene sheet (formation of nanopits and nanobumps), transformation of mechanical properties of graphene on a substrate structure took place. Such laser modified graphene area is larger than (but of the order of) the irradiation spot size. Its appearance is related to laser induced radial extension of an adsorbed water nanolayer intercalated between graphene and substrate. It is shown that the process of water layer lateral migration has a reversible character. This effect is proved by laser spot shift and sequential irradiation.

  1. Ultrathin and ultrasmooth Au films as transparent electrodes in ITO-free organic light-emitting devices.

    PubMed

    Bi, Yan-Gang; Feng, Jing; Ji, Jin-Hai; Chen, Yang; Liu, Yu-Shan; Li, Yun-Fei; Liu, Yue-Feng; Zhang, Xu-Lin; Sun, Hong-Bo

    2016-05-21

    An ultrathin, ultrasmooth and flexible Au film as an alternative of the indium-tin oxide (ITO) electrode in organic light-emitting devices (OLEDs) has been reported. The 7 nm Au film shows excellent surface morphology, optical and electronic characteristics including a root-mean-square roughness of 0.35 nm, a high transparency of 72% at 550 nm, and a sheet resistance of 23.75 Ω sq(-1). These features arise from the surface modification of the glass substrate by using a SU-8 film, which fixes metal atoms via chemical bond interactions between Au and SU-8 film to suppress the island growth mode. A 17% enhancement in current efficiency has been obtained from the OLEDs based on the ultrathin Au electrodes compared to that of the devices with the ITO electrodes. The OLEDs with the ultrathin Au/SU-8 anodes exhibit high flexibility and mechanical robustness. PMID:27128168

  2. Ultrathin and ultrasmooth Au films as transparent electrodes in ITO-free organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Bi, Yan-Gang; Feng, Jing; Ji, Jin-Hai; Chen, Yang; Liu, Yu-Shan; Li, Yun-Fei; Liu, Yue-Feng; Zhang, Xu-Lin; Sun, Hong-Bo

    2016-05-01

    An ultrathin, ultrasmooth and flexible Au film as an alternative of the indium-tin oxide (ITO) electrode in organic light-emitting devices (OLEDs) has been reported. The 7 nm Au film shows excellent surface morphology, optical and electronic characteristics including a root-mean-square roughness of 0.35 nm, a high transparency of 72% at 550 nm, and a sheet resistance of 23.75 Ω sq-1. These features arise from the surface modification of the glass substrate by using a SU-8 film, which fixes metal atoms via chemical bond interactions between Au and SU-8 film to suppress the island growth mode. A 17% enhancement in current efficiency has been obtained from the OLEDs based on the ultrathin Au electrodes compared to that of the devices with the ITO electrodes. The OLEDs with the ultrathin Au/SU-8 anodes exhibit high flexibility and mechanical robustness.An ultrathin, ultrasmooth and flexible Au film as an alternative of the indium-tin oxide (ITO) electrode in organic light-emitting devices (OLEDs) has been reported. The 7 nm Au film shows excellent surface morphology, optical and electronic characteristics including a root-mean-square roughness of 0.35 nm, a high transparency of 72% at 550 nm, and a sheet resistance of 23.75 Ω sq-1. These features arise from the surface modification of the glass substrate by using a SU-8 film, which fixes metal atoms via chemical bond interactions between Au and SU-8 film to suppress the island growth mode. A 17% enhancement in current efficiency has been obtained from the OLEDs based on the ultrathin Au electrodes compared to that of the devices with the ITO electrodes. The OLEDs with the ultrathin Au/SU-8 anodes exhibit high flexibility and mechanical robustness. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00599c

  3. Surface modification of polymeric substrates by plasma-based ion implantation

    NASA Astrophysics Data System (ADS)

    Okuji, S.; Sekiya, M.; Nakabayashi, M.; Endo, H.; Sakudo, N.; Nagai, K.

    2006-01-01

    Plasma-based ion implantation (PBII) as a tool for polymer modification is studied. Polymeric films have good performances for flexible use, such as food packaging or electronic devices. Compared with inorganic rigid materials, polymers generally have large permeability for gases and moisture, which causes packaged contents and devices to degrade. In order to add a barrier function, surface of polymeric films are modified by PBII. One of the advantageous features of this method over deposition is that the modified surface does not have peeling problem. Besides, micro-cracks due to mechanical stress in the modified layer can be decreased. From the standpoint of mass production, conventional ion implantation that needs low-pressure environment of less than 10-3 Pa is not suitable for continuous large-area processing, while PBII works at rather higher pressure of several Pa. In terms of issues mentioned above, PBII is one of the most expected techniques for modification on flexible substrates. However, the mechanism how the barrier function appears by ion implantation is not well explained so far. In this study, various kinds of polymeric films, including polyethyleneterephthalate (PET), are modified by PBII and their barrier characteristics that depend on the ion dose are evaluated. In order to investigate correlations of the barrier function with implanted ions, modified surface is analyzed with X-ray photoelectron spectroscopy (XPS). It is assumed that the diffusion and sorption coefficients are changed by ion implantation, resulting in higher barrier function.

  4. Dialdehyde derivatives of purine mononucleotides: substrate properties and affinity modification of myosin ATPase

    SciTech Connect

    Grishin, M.N.; Kodentsova, V.M.; Abdraimova, U.A.; Nikolaeva, O.P.; Petushkova, E.V.

    1986-03-20

    It was established that the dialdehyde derivative of ATP (oxo-ATP) is a good substrate of the Ca-ATPase of heavy meromyosin: (1.2-1.4) x 10/sup -4/ M; V = V/sub ATP/. At the same time, it is capable of inducing irreversible inhibition of the enzyme. Since oxo-ATP is rapidly digested by myosin, forming oxo-ADP, this inhibition is a consequence of the interaction of the enzyme with oxo-ADP. It was shown that the inhibition of heavy meromyosin (HMM), by oxo-ADP occurs according to the kinetics characteristic of affinity modification; moreover, ATP entirely protects HMM from the loss of activity. Similar data on the irreversible inhibition of ATPase activity under the action of oxo-ADP were obtained in the case of myosin, heavy meromyosin, subfragment-1, and natural actomyosin, as well as in the absence of divalent cations, which is evidence of modification of the active site of myosin ATPase.

  5. Structural modification of TiAlN coatings by preliminary Ti Ion bombardment of a steel substrate

    NASA Astrophysics Data System (ADS)

    Shugurov, A. R.; Akulinkin, A. A.; Panin, A. V.; Perevalova, O. B.; Sergeev, V. P.

    2016-03-01

    The TiAlN coatings deposited onto steel 12Cr18Ni9Ti substrates before and after preliminary treatment by Ti ion beams are studied by X-ray diffraction, transmission electron microscopy, atomic force microscopy, and nanoindentation. The modification of the surface layer of a substrate is shown to change the structure and the preferred orientation of the coatings. The mechanical properties of the TiAlN coatings are found to depend substantially on the ion bombardment time.

  6. ITO/InP solar cells: A comparison of devices fabricated by ion beam and RF sputtering of the ITO

    NASA Technical Reports Server (NTRS)

    Coutts, T. J.

    1987-01-01

    This work was performed with the view of elucidating the behavior of indium tin oxide/indium phosphide (ITO/InP) solar cells prepared by RF and ion beam sputtering. It was found that using RF sputter deposition of the ITO always leads to more efficient devices than ion beam sputter deposition. An important aspect of the former technique is the exposure of the single crystal p-InP substrates to a very low plasma power prior to deposition. Substrates treated in this manner have also been used for ion beam deposition of ITO. In this case the cells behave very similarly to the RF deposited cells, thus suggesting that the lower power plasma exposure (LPPE) is the crucial process step.

  7. Rapid fabrication of a silicon modification layer on silicon carbide substrate.

    PubMed

    Bai, Yang; Li, Longxiang; Xue, Donglin; Zhang, Xuejun

    2016-08-01

    We develop a kind of magnetorheological (MR) polishing fluid for the fabrication of a silicon modification layer on a silicon carbide substrate based on chemical theory and actual polishing requirements. The effect of abrasive concentration in MR polishing fluid on material removal rate and removal function shape is investigated. We conclude that material removal rate will increase and tends to peak value as the abrasive concentration increases to 0.3 vol. %, and the removal function profile will become steep, which is a disadvantage to surface frequency error removal at the same time. The removal function stability is also studied and the results show that the prepared MR polishing fluid can satisfy actual fabrication requirements. An aspheric reflective mirror of silicon carbide modified by silicon is well polished by combining magnetorheological finishing (MRF) using two types of MR polishing fluid and computer controlled optical surfacing (CCOS) processes. The surface accuracy root mean square (RMS) is improved from 0.087λ(λ=632.8  nm) initially to 0.020λ(λ=632.8  nm) in 5.5 h total and the tool marks resulting from MRF are negligible. The PSD analysis results also shows that the final surface is uniformly polished. PMID:27505358

  8. Room-temperature fabricated, fully transparent resistive memory based on ITO/CeO2/ITO structure for RRAM applications

    NASA Astrophysics Data System (ADS)

    Ismail, Muhammad; Rana, Anwar Manzoor; Talib, Ijaz; Tsai, Tsung-Ling; Chand, Umesh; Ahmed, Ejaz; Nadeem, Muhammad Younus; Aziz, Abdul; Shah, Nazar Abbas; Hussain, Muhammad

    2015-01-01

    Fully transparent resistive random access memory (TRRAM) device based on CeO2 as active layer using indium-tin-oxide (ITO) electrodes was fabricated on glass substrate. The ITO/CeO2/ITO memory device shows 81% transmission of visible light, optical band gap energy of 4.05 eV, and exhibits reliable bipolar resistive switching behavior. X-ray diffraction of CeO2 thin films demonstrated a weak polycrystalline phase. The low field conduction is dominated by Ohmic type while Poole-Frenkel effect is responsible for conduction in the high field region. The device reliability investigations, such as data retention (over 104 s) under applied stress and endurance tests conducted at room temperature and 85 °C show potential of our TRRAM devices for future non-volatile memory applications.

  9. Optical properties of ITO nanocoatings for photovoltaic and energy building applications

    NASA Astrophysics Data System (ADS)

    Kaplani, E.; Kaplanis, S.; Panagiotaras, D.; Stathatos, E.

    2014-10-01

    Targeting energy savings in buildings, photovoltaics and other sectors, significant research activity is nowadays focused on the production of spectral selective nanocoatings. In the present study an ITO coating on glass substrate is prepared from ITO powder, characterized and analysed. The spectral transmittance and reflectance of the ITO coated glass and of two other commercially developed ITO coatings on glass substrate were measured and compared. Furthermore, a simulation algorithm was developed to determine the optical properties of the ITO coatings in the visible, solar and near infrared regions in order to assess the impact of the ITO coatings in the energy performance of buildings, and particularly the application in smart windows. In addition, the current density produced by a PV assuming each of the ITO coated glass served as a cover was computed, in order to assess their effect in PV performance. The preliminary ITO coating prepared and the two other coatings exhibit different optical properties and, thus, have different impact on energy performance. The analysis assists in a better understanding of the desired optical properties of nanocoatings for improved energy performance in PV and buildings.

  10. Nanoscale surface modification of plastic substrates for advanced tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Donkov, N.; Safonov, V.; Zykova, A.; Smolik, J.; Rogovska, R.; Goltsev, A.; Dubrava, T.; Rossokha, I.; Georgieva, V.

    2012-12-01

    Modified surface properties such as composition, nano roughness, wettability have effect on the most important processes at biomaterial interface. The research of stem cells (MSCs) adhesive potential, morphology, phenotypical characteristics on oxide coated and plastic substrate with different surface parameters was made. The oxide coatings deposition on plastic substrates shifts the surface properties at the more hydrophilic region and results in next positive cell/ biomaterial response in vitro tests. The MSCs marker number increases on the oxide nano structural surface of plastic substrates.

  11. Molecular bases for the recognition of short peptide substrates and cysteine-directed modifications of human insulin-degrading enzyme

    PubMed Central

    Malito, Enrico; Ralat, Luis A.; Manolopoulou, Marika; Tsay, Julie L.; Wadlington, Natasha L.; Tang, Wei-Jen

    2009-01-01

    Insulin degrading enzyme (IDE) utilizes a large catalytic chamber to selectively bind and degrade peptide substrates such as insulin and amyloid β (Aβ). Tight interactions with substrates occur at an exosite located ~30Å away from the catalytic center that anchors the N-terminus of substrates to facilitate binding and subsequent cleavages at the catalytic site. However, IDE also degrades peptide substrates that are too short to occupy both the catalytic site and the exosite simultaneously. Here, we use kinins as a model system to address the kinetics and regulation of human IDE with short peptides. IDE specifically degrades bradykinin and kallidin at the Pro/Phe site. A 1.9Å crystal structure of bradykinin-bound IDE reveals the binding of bradykinin to the exosite, and not to the catalytic site. In agreement with observed high Km values, this suggests low affinity of bradykinin for IDE. This structure also provides the molecular basis on how the binding of short peptides at the exosite could regulate substrate recognition. We also found that human IDE is potently inhibited by physiologically relevant concentrations of S-nitrosylation and oxidation agents. Cysteine-directed modifications play a key role, since an IDE mutant devoid of all thirteen cysteines is insensitive to the inhibition by S-nitroso-glutathione, hydrogen peroxide, or N-ethylmaleimide. Specifically, cysteine 819 of human IDE is located inside the catalytic chamber pointing towards an extended hydrophobic pocket and is critical for the inactivation. Thiol-directed modification of this residue likely causes local structural perturbation to reduce substrate binding and catalysis. PMID:18986166

  12. Modification of Switchgrass Substrate pH Using Compost, Peatmoss, and Elemental Sulfur

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum) biomass is being evaluated as a potential alternative to pine bark as the primary potting component in containerized nursery crops. Substrates comprised entirely of switchgrass have higher pH than what is considered desirable in container substrates. The objective of...

  13. Modification of the surface state of rough substrates by two different varnishes and influence on the reflected light

    NASA Astrophysics Data System (ADS)

    Elias, Mady; René de la Rie, E.; Delaney, John K.; Charron, Eric; Morales, Kathryn M.

    2006-10-01

    Modification of the visual appearance when a rough surface is covered by a varnish is mostly attributed to the levelling of the substrate surface, which depends on the molecular weight of the varnish. The topography of varnished surfaces, however, has never been measured directly. Surfaces of varnishes applied over glass substrates of varying roughness were studied, therefore, using mechanical profilometry. Two different varnishes made with a low and a high molecular weight resin were studied. Both varnishes lower the r.m.s. roughness of the substrates and filter the high spatial frequencies. These results are amplified for the varnish containing the low molecular weight resin. The light reflected by the varnished samples is modelled from these topographical data. Its angular distribution, calculated from the probability density of slopes is presented, taking into account separately the air/varnish and the varnish/substrate interfaces. These analyses are presented in a back-scattering configuration. They show that varnishing significantly reduces the angular width of the reflected light and that this effect is magnified for the low molecular weight resin. Modelling furthermore shows that the influence of the roughness of the varnish/substrate interface is negligible in the total reflected light.

  14. Atom-scale covalent electrochemical modification of single-layer graphene on SiC substrates by diaryliodonium salts

    DOE PAGESBeta

    Gearba, Raluca I.; Mueller, Kory M.; Veneman, Peter A.; Holliday, Bradley J.; Chan, Calvin K.; Stevenson, Keith J.

    2015-05-09

    Owing to its high conductivity, graphene holds promise as an electrode for energy devices such as batteries and photovoltaics. However, to this end, the work function and doping levels in graphene need to be precisely tuned. One promising route for modifying graphene’s electronic properties is via controlled covalent electrochemical grafting of molecules. We show that by employing diaryliodonium salts instead of the commonly used diazonium salts, spontaneous functionalization is avoided. This then allows for precise tuning of the grafting density. Moreover, by employing bis(4-nitrophenyl)iodonium(III) tetrafluoroborate (DNP) salt calibration curves, the surface functionalization density (coverage) of glassy carbon was controlled usingmore » cyclic voltammetry in varying salt concentrations. These electro-grafting conditions and calibration curves translated directly over to modifying single layer epitaxial graphene substrates (grown on insulating 6H-SiC (0 0 0 1)). In addition to quantifying the functionalization densities using electrochemical methods, samples with low grafting densities were characterized by low-temperature scanning tunneling microscopy (LT-STM). We show that the use of buffer-layer free graphene substrates is required for clear observation of the nitrophenyl modifications. Furthermore, atomically-resolved STM images of single site modifications were obtained, showing no preferential grafting at defect sites or SiC step edges as supposed previously in the literature. Most of the grafts exhibit threefold symmetry, but occasional extended modifications (larger than 4 nm) were observed as well.« less

  15. Atom-scale covalent electrochemical modification of single-layer graphene on SiC substrates by diaryliodonium salts

    SciTech Connect

    Gearba, Raluca I.; Mueller, Kory M.; Veneman, Peter A.; Holliday, Bradley J.; Chan, Calvin K.; Stevenson, Keith J.

    2015-05-09

    Owing to its high conductivity, graphene holds promise as an electrode for energy devices such as batteries and photovoltaics. However, to this end, the work function and doping levels in graphene need to be precisely tuned. One promising route for modifying graphene’s electronic properties is via controlled covalent electrochemical grafting of molecules. We show that by employing diaryliodonium salts instead of the commonly used diazonium salts, spontaneous functionalization is avoided. This then allows for precise tuning of the grafting density. Moreover, by employing bis(4-nitrophenyl)iodonium(III) tetrafluoroborate (DNP) salt calibration curves, the surface functionalization density (coverage) of glassy carbon was controlled using cyclic voltammetry in varying salt concentrations. These electro-grafting conditions and calibration curves translated directly over to modifying single layer epitaxial graphene substrates (grown on insulating 6H-SiC (0 0 0 1)). In addition to quantifying the functionalization densities using electrochemical methods, samples with low grafting densities were characterized by low-temperature scanning tunneling microscopy (LT-STM). We show that the use of buffer-layer free graphene substrates is required for clear observation of the nitrophenyl modifications. Furthermore, atomically-resolved STM images of single site modifications were obtained, showing no preferential grafting at defect sites or SiC step edges as supposed previously in the literature. Most of the grafts exhibit threefold symmetry, but occasional extended modifications (larger than 4 nm) were observed as well.

  16. Surface modification of SERS substrates with plasma-polymerized trimethylsilane nanocoating

    NASA Astrophysics Data System (ADS)

    Kim, Young Jo; Sun, Xin; Jones, John E.; Lin, Mengshi; Yu, Qingsong; Li, Hao

    2015-03-01

    Surface-enhanced Raman scattering (SERS) substrates were modified by depositing a nanometer-thick polymer coating on top of SERS-active surface. This thin hydrophobic nanocoating, achieved by low temperature plasma polymerization of trimethylsilane, was found to reduce surface energy of SERS substrate and in turn help relieve the analyte spreading on the surface of SERS substrates. Detection of melamine molecules with these surface-modified SERS substrates showed that this plasma nanocoating improved, not significantly though, SERS sensitivity in comparison with unmodified SERS substrates. It is believed that the increased hydrophobicity induced by this plasma nanocoating had two folds of beneficial effects on SERS sensitivity. First, the as-produced hydrophobic surface gave rise to preconcentration effect due to the reduced contact area between analyte molecules and the substrate surface. Second, the decreased surface energy of SERS substrates was helpful in placing analyte molecules in SERS hot spots. These two combined gains were deemed to outweigh the loss of SERS sensitivity caused by enlarged distance between metal surface and analyte molecules.

  17. Origin of the bottlenecks in preparing anodized aluminum oxide (AAO) templates on ITO glass.

    PubMed

    Foong, Thelese R B; Sellinger, Alan; Hu, Xiao

    2008-11-25

    Nanoporous anodic alumina (AAO) templates are routinely created with ease on substrates, particularly Si wafers. However, the inability to stabilize Al anodization on indium tin oxide (ITO) glass is a key stumbling block that has prevented AAO-assisted deposition of nanomaterial arrays extending from ITO that are attractive for a range of opto-electronic applications (e.g., solar cells and photonic devices). We report on the processing of stable AAO templates directly on ITO substrates by utilizing an ultrathin (0.3 nm) adhesion/passivation layer of Ti between ITO and Al. Precise control of the Ti layer thickness to within the subnanometer (0.2-0.5 nm) range is essential for the anodization process for two factors: (1) to prevent the delamination of Al and destruction of ITO; and (2) to prevent the formation of thick barrier layers at the bottom of the pore channels, which prevent pore connectivity to the conductive ITO substrate. We explore the complex correlation between the electrical properties of substrates (and interlayers) and barrier layer formation and further highlight the criteria for successful barrier layer removal. PMID:19206390

  18. Modification of Ti6Al4V Substrates with Well-defined Zwitterionic Polysulfobetaine Brushes for Improved Surface Mineralization

    PubMed Central

    2015-01-01

    Osteoconductive mineral coatings are beneficial for improving the osteointegration of metallic orthopedic/dental implants, but achieving adequate structural integration between the surface minerals and underlying metallic substrates has been a significant challenge. Here, we report covalent grafting of zwitterionic poly(sulfobetaine methacrylate) (pSBMA) brushes on the Ti6Al4V substrates to promote the surface-mineralization of hydroxyapatite with enhanced surface mineral coverage and mineral-substrate interfacial adhesion. We first optimized the atom transfer radical polymerization (ATRP) conditions for synthesizing pSBMA polymers in solution. Well-controlled pSBMA polymers (relative molecular weight up to 26kD, PDI = 1.17) with high conversions were obtained when the ATRP was carried out in trifluoroethanol/ionic liquid system at 60 °C. Applying identical polymerization conditions, surface-initiated atom transfer radical polymerization (SI-ATRP) was carried out to graft zwitterionic pSBMA brushes (PDI < 1.20) from the Ti6Al4V substrates, generating a stable superhydrophilic and low-fouling surface coating without compromising the bulk mechanic property of the Ti6Al4V substrates. The zwitterionic pSBMA surface brushes, capable of attracting both cationic and anionic precursor ions during calcium phosphate apatite mineralization, increased the surface mineral coverage from 32% to 71%, and significantly reinforced the attachment of the apatite crystals on the Ti6Al4V substrate. This facile approach to surface modification of metallic substrates can be exploited to generate multifunctional polymer coatings and improve the performance of metallic implants in skeletal tissue engineering and orthopedic and dental care. PMID:24828749

  19. Modification of Ti6Al4V substrates with well-defined zwitterionic polysulfobetaine brushes for improved surface mineralization.

    PubMed

    Liu, Pingsheng; Domingue, Emily; Ayers, David C; Song, Jie

    2014-05-28

    Osteoconductive mineral coatings are beneficial for improving the osteointegration of metallic orthopedic/dental implants, but achieving adequate structural integration between the surface minerals and underlying metallic substrates has been a significant challenge. Here, we report covalent grafting of zwitterionic poly(sulfobetaine methacrylate) (pSBMA) brushes on the Ti6Al4V substrates to promote the surface-mineralization of hydroxyapatite with enhanced surface mineral coverage and mineral-substrate interfacial adhesion. We first optimized the atom transfer radical polymerization (ATRP) conditions for synthesizing pSBMA polymers in solution. Well-controlled pSBMA polymers (relative molecular weight up to 26 kD, PDI = 1.17) with high conversions were obtained when the ATRP was carried out in trifluoroethanol/ionic liquid system at 60 °C. Applying identical polymerization conditions, surface-initiated atom transfer radical polymerization (SI-ATRP) was carried out to graft zwitterionic pSBMA brushes (PDI < 1.20) from the Ti6Al4V substrates, generating a stable superhydrophilic and low-fouling surface coating without compromising the bulk mechanic property of the Ti6Al4V substrates. The zwitterionic pSBMA surface brushes, capable of attracting both cationic and anionic precursor ions during calcium phosphate apatite mineralization, increased the surface mineral coverage from 32% to 71%, and significantly reinforced the attachment of the apatite crystals on the Ti6Al4V substrate. This facile approach to surface modification of metallic substrates can be exploited to generate multifunctional polymer coatings and improve the performance of metallic implants in skeletal tissue engineering and orthopedic and dental care. PMID:24828749

  20. Recent advances in the ITO/InP solar cell

    NASA Technical Reports Server (NTRS)

    Gessert, T. A.; Li, X.; Wanlass, M. W.; Coutts, T. J.

    1991-01-01

    It was demonstrated that Indium Tin Oxide (ITO)/InP solar cells can now be made on as-received p(-) bulk substrates which are of nearly equal quality to those which could previously only be made on epitaxially grown p(-) InP base layers. Although this advancement is due in part to both increases in substrate quality and a better understanding of back contact formation, it appears that the passivation/compensation effects resulting from having H2 in the sputtering gas tends to reduce significantly the performance differences previously observed between these two substrates. It is shown that since high efficiency ITO/InP cells can be made from as-received substrates, and since the type conversion process is not highly spatially dependent, large area ITO/InP cells (4 sq cm) with efficiencies approaching 17 percent (Global) can be made. Furthermore, the measured open circuit voltages (V sub OC) and quantum efficiencies (QEs) from these large cells suggest that, when they are processed using optimum grid designs, the efficiencies will be nearly equal to that of the smaller cells thus far produced. It has been shown, through comparative experiments involving ITO/InP and IO/InP cells, that Sn may not be the major cause of type conversion of the InP surface and thus further implies that the ITO may not be an essential element in this type of device. Specifically, very efficient photovoltaic solar cells were made by sputtering (Sn free) In2O3 showing that type conversion and subsequent junction formation will occur even in the absence of the sputtered SN species. The result suggests that sputter damage may indeed be the important mechanism(s) of type conversion. Finally, an initial study of the stability of the ITO/InP cell done over the course of about one year has indicated that the J(sub SC) (short circuit current) and the fill factor (FF) are measurably stable within experimental certainty.

  1. Preparation of a hole transport layer tethered to ITO surface via a self-assembled monolayer with reactive terminal group

    NASA Astrophysics Data System (ADS)

    Hagihara, Yuya; Kim, Seong-Ho; Tanaka, Kuniaki; Advincula, Rigoberto C.; Usui, Hiroaki

    2014-01-01

    Characteristics of a junction between a polymer thin film and an indium-tin oxide (ITO) substrate was controlled by forming covalent chemical bonds at the interface through self-assembled monolayers (SAMs) with reactive terminal groups. For this purpose, SAMs with vinyl, epoxide, and benzophenone terminal groups were formed on ITO substrates, on which a vinyl derivative of a hole transport molecule was vapor-deposited, and then annealed in vacuum. This procedure produced a polymer layer strongly attached to the substrate surface. It was also found that the charge injection from the ITO electrode to the polymer layer can be improved by chemically tethering the interface via the SAMs.

  2. Modification of Bi:YIG film properties by substrate surface ion pre-treatment

    SciTech Connect

    Shaposhnikov, A.N.; Prokopov, A.R.; Karavainikov, A.V.; Berzhansky, V.N.; Mikhailova, T.V.; Kotov, V.A.; Balabanov, D.E.; Sharay, I.V.; Salyuk, O.Y.; Vasiliev, M.; Golub, V.O.

    2014-07-01

    Highlights: • Effects of substrates ion beam treatment on magnetoptical properties Bi:YIG films. • Substrate surface damage results in sign inversion of the magneto-optical effects. • Atomically smooth films growth takes place on low energy ions treated substrates. • High energy ions treatment results in selective nucleation mechanism of the growth. - Abstract: The effect of a controlled ion beam pre-treatment of (1 1 1)-oriented Gd{sub 3}Ga{sub 5}O{sub 12} substrates on the magneto-optical properties and surface morphology of the ultrathin bismuth-substituted yttrium–iron garnet films with a composition Bi{sub 2.8}Y{sub 0.2}Fe{sub 5}O{sub 12} was studied. It has been shown that the observed sign inversion of magneto-optical effects (Faraday rotation and magnetic circular dichroism) observed in films that were deposited on the GGG substrate pre-treated by 1 keV and 4 keV Ar{sup +} ion beams is a result of the substrate surface amorphization caused by the ion bombardment.

  3. Laser selective patterning of ITO on flexible PET for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Xiao, Shizhou; Gröger, Björn; Fernandes, Susana Abreu; Ostendorf, Andreas

    2011-03-01

    Flexible organic photovoltaics have gained increasing interests during the last decades. Toward increasing the efficiency and decreasing the cost per Watt, they are on their way to the market. The approach of laser patterning technology has been expected to motivate the industrialization of organic photovoltaics. In this paper high repetition picosecond laser radiation fabricated trenches of ITO on flexible PET (Polyethylene terephthalate) substrate are presented. In order to obtain clean removal ITO layer without damaging PET substrate, 1064nm, 532nm and 355nm wavelengths with different laser fluencies and scanning strategies are applied and optimized. The results reveal the different principles for ablation of ITO layer with different wavelengths. The ITO layer is successfully and selectively removed by 1064nm laser radiation with 0.63J/cm2 fluence and 4m/s scanning speed.

  4. 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.

  5. Modification of dislocation behavior in GaN overgrown on engineered AlN film-on-bulk Si substrate

    NASA Astrophysics Data System (ADS)

    Tungare, Mihir; Weng, Xiaojun; Leathersich, Jeffrey M.; Suvarna, Puneet; Redwing, Joan M.; (Shadi) Shahedipour-Sandvik, F.

    2013-04-01

    The changes that the AlN buffer and Si substrate undergo at each stage of our substrate engineering process, previously shown to lead to a simultaneous and substantial reduction in film crack density and dislocation density in overgrown GaN, are presented. Evidence of ion-implantation assisted grain reorientation for AlN islands coupled with physical isolation from the bulk Si substrate prove to be the dominating driving forces. This is further emphasized with x-ray diffraction analysis that demonstrates a reduction in the in-plane lattice constant of AlN from 3.148 Å to 3.113 Å and a relative change in rotation of AlN islands by 0.135° with regard to the Si substrate after substrate engineering. Misfit dislocations at the AlN-Si interface and disorder that is normally associated with formation of amorphous SiNx at this interface are considered to be two of the major contributors to dislocation nucleation within overgrown GaN. Following our technique, the disappearance of disorder at the AlN-Si interface is observed. Extensive ellipsometry and transmission electron microscopy suggests that larger AlN islands with a smoother surface morphology could further reduce the dislocation density below that previously reported. A 1.2 μm GaN layer deposited on an AlN buffer with larger islands and smoother morphology exhibits a 14× reduction in surface pit density after undergoing the ion-implantation assisted substrate modification technique.

  6. LEDs on curved ceramic substrate with primary optics for modification of luminous intensity

    NASA Astrophysics Data System (ADS)

    Wei, An-Chi; Sze, Jyh-Rou; Chern, Jyh-Long

    2011-10-01

    Unlike the conventional LED luminary with a planar substrate and only the forward emission, the proposed LED luminary with a curved ceramic substrate can perform both the forward and the backward emissions. Assembled with the proper primary optics, an illustrated LED bulb has been designed, fabricated and measured. The measured luminous intensity of the LED bulb has shown the backward emission and designed distribution with the beam-angle of 133°. To broaden the application areas, such a LED bulb on a curved substrate has been modularized as a streetlight. The measured results of the proposed streetlight have shown that the beam angle of the luminous intensity and the luminaire efficiency are 132° and 86%, respectively. Meanwhile, its luminous characteristics also fit the standard for lighting design of urban roads.asei.c

  7. Agarose-Based Substrate Modification Technique for Chemical and Physical Guiding of Neurons In Vitro.

    PubMed

    Krumpholz, Katharina; Rogal, Julia; El Hasni, Akram; Schnakenberg, Uwe; Bräunig, Peter; Bui-Göbbels, Katrin

    2015-08-26

    A new low cost and highly reproducible technique is presented that provides patterned cell culture substrates. These allow for selective positioning of cells and a chemically and mechanically directed guiding of their extensions. The patterned substrates consist of structured agarose hydrogels molded from reusable silicon micro templates. These templates consist of pins arranged equidistantly in squares, connected by bars, which mold corresponding wells and channels in the nonadhesive agarose hydrogel. Subsequent slice production with a standard vibratome, comprising the described template pattern, completes substrate production. Invertebrate neurons of locusts and pond snails are used for this application as they offer the advantage over vertebrate cells as being very large and suitable for cultivation in low cell density. Their neurons adhere to and grow only on the adhesive areas not covered by the agarose. Agarose slices of 50 μm thickness placed on glass, polystyrene, or MEA surfaces position and immobilize the neurons in the wells, and the channels guide their neurite outgrowth toward neighboring wells. In addition to the application with invertebrate neurons, the technique may also provide the potential for the application of a wide range of cell types. Long-term objective is the achievement of isolated low-density neuronal networks on MEAs or different culture substrates for various network analysis applications. PMID:26237337

  8. ITOS meteorological satellite system: TIROS M spacecraft (ITOS 1), volume 1

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The ITOS system and mission are described along with the design of the TIROS M spacecraft, and the ITOS ground complex. The command subsystems, and the primary environmental sensor subsystem are discussed.

  9. Modification of graphene chemistry for metal nanoparticle growth: the effect of substrate selection

    NASA Astrophysics Data System (ADS)

    Zaniewski, Anna; Nemanich, Robert

    2014-03-01

    Graphene and metal nanoparticle composites are a promising class of materials with unique electronic, optical, and chemical properties. In this work, graphene is used as a reducing surface to grow metal nanoparticles out of solution-based metal precursors. The nanoparticle formation is found to strongly depend upon the graphene substrate selection. The studied substrates include silicon oxide, silicon, lithium niobate, and copper. Our results indicate that the chemical properties of graphene depend upon this selection. For example, for the same reaction times and concentration, the reduction of gold chloride to gold nanoparticles on graphene/lithium niobate results in 3% nanoparticle coverage compared to 20% coverage on graphene/silicon and 60% on graphene/copper. This work is supported through the National Science Foundation under Grant # DMR-1206935 .

  10. Surface modification for patterned cell growth on substrates with pronounced topographies using sacrificial photoresist and parylene-C peel-off

    NASA Astrophysics Data System (ADS)

    Larramendy, Florian; Yoshida, Shotaro; Jalabert, Laurent; Takeuchi, Shoji; Paul, Oliver

    2016-09-01

    A range of methods including soft lithography are available for patterning protein layers for cell adhesion on quasi-planar substrates. Suitably structured, these layers favor the geometrically constrained, controlled growth of cells and the development of cellular extensions on them. For this purpose, the ability to control the shape and dimension of cell-adhesive areas with high precision is crucial. For more advanced studies of cell interactions, the surface modification or functionalization of substrates with complex topographies is desirable. This paper describes a simple technique allowing to produce surface modification patterns using delicate molecules such as laminin on substrates exhibiting pronounced topographies with recessed and protruding microstructures. The technique is based on the combination of sacrificial photoresist structures with a connected parylene-C layer. This layer locally adheres to the substrate wherever the substrate needs to be protected against the surface modification. After surface modification, the parylene-C layer is peeled off. Patterns comprising arbitrary networks of modified and unmodified substrate areas can thus be realized. We demonstrate the technique with the guided growth of neuron-like PC12 cells on networks of laminin lines on substrates structured with micropillars and microwells.

  11. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253. All...) Qualification as an ITO. The ITO of a tribe in Oklahoma must document to the satisfaction of FNS that the ITO meets the definition of an ITO in § 254.2, is organized under the provisions of the Oklahoma...

  12. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253. All...) Qualification as an ITO. The ITO of a tribe in Oklahoma must document to the satisfaction of FNS that the ITO meets the definition of an ITO in § 254.2, is organized under the provisions of the Oklahoma...

  13. Characteristics of ITO films with oxygen plasma treatment for thin film solar cell applications

    SciTech Connect

    Park, Yong Seob; Kim, Eungkwon; Hong, Byungyou; Lee, Jaehyoeng

    2013-12-15

    Graphical abstract: The effect of O{sub 2} plasma treatment on the surface and the work function of ITO films. - Highlights: • ITO films were prepared on the glass substrate by RF magnetron sputtering method. • Effects of O{sub 2} plasma treatment on the properties of ITO films were investigated. • The work function of ITO film was changed from 4.67 to 5.66 eV by plasma treatment. - Abstract: The influence of oxygen plasma treatment on the electro-optical and structural properties of indium-tin-oxide films deposited by radio frequency magnetron sputtering method were investigated. The films were exposed at different O{sub 2} plasma powers and for various durations by using the plasma enhanced chemical vapor deposition (PECVD) system. The resistivity of the ITO films was almost constant, regardless of the plasma treatment conditions. Although the optical transmittance of ITO films was little changed by the plasma power, the prolonged treatment slightly increased the transmittance. The work function of ITO film was changed from 4.67 eV to 5.66 eV at the plasma treatment conditions of 300 W and 60 min.

  14. Highly Stretchable and Flexible Graphene/ITO Hybrid Transparent Electrode

    NASA Astrophysics Data System (ADS)

    Liu, Juhua; Yi, Yaohua; Zhou, Yihua; Cai, Huafei

    2016-02-01

    The flexible hybrid transparent electrode was prepared by a two-step process: graphene film was firstly grown on Cu foil by modified thermal chemical vapor deposition (CVD) and then transferred onto indium tin oxide (ITO) electrode on the polyethylene terephthalate (PET) substrate. The quality of the graphene is characterized by various analytic techniques, including the AFM, SEM, TEM, and Raman spectroscopy. The gradient flux was found to be beneficial to decrease defect. The thickness, morphology, light transmittance, and electromechanical properties of three conductive electrodes were investigated and compared. The outcomes show that the hybrid electrode could resist mechanical force and the results are better than original ITO electrode. It may be a potential trend to apply the graphene to other conducts in the flexible transparent conductive field.

  15. Highly Stretchable and Flexible Graphene/ITO Hybrid Transparent Electrode.

    PubMed

    Liu, Juhua; Yi, Yaohua; Zhou, Yihua; Cai, Huafei

    2016-12-01

    The flexible hybrid transparent electrode was prepared by a two-step process: graphene film was firstly grown on Cu foil by modified thermal chemical vapor deposition (CVD) and then transferred onto indium tin oxide (ITO) electrode on the polyethylene terephthalate (PET) substrate. The quality of the graphene is characterized by various analytic techniques, including the AFM, SEM, TEM, and Raman spectroscopy. The gradient flux was found to be beneficial to decrease defect. The thickness, morphology, light transmittance, and electromechanical properties of three conductive electrodes were investigated and compared. The outcomes show that the hybrid electrode could resist mechanical force and the results are better than original ITO electrode. It may be a potential trend to apply the graphene to other conducts in the flexible transparent conductive field. PMID:26920153

  16. Catalyst-free growth of ZnO nanowires on ITO seed/glass by thermal evaporation method: Effects of ITO seed layer thickness

    NASA Astrophysics Data System (ADS)

    Alsultany, Forat H.; Hassan, Z.; Ahmed, Naser M.

    2016-07-01

    A seed/catalyst-free growth of ZnO nanowires (ZnO-NWs) on a glass substrate were successfully fabricated using thermal evaporation technique. These nanowires were grown on ITO seed layers of different thicknesses of 25 and 75 nm, which were deposited on glass substrates by radio frequency (RF) magnetron sputtering. Prior to synthesized ITO nanowires, the sputtered ITO seeds were annealed using the continuous wave (CW) CO2 laser at 450 °C in air for 15 min. The effect of seed layer thickness on the morphological, structural, and optical properties of ZnO-NWs were systematically investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and UV-Vis spectrophotometer.

  17. Chemical mechanical polishing characteristics of ITO thin film prepared by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Lee, Kang-Yeon; Choi, Gwon-Woo; Kim, Yong-Jae; Choi, Youn-Ok; Kim, Nam-Oh

    2012-02-01

    Indium-tin-oxide (ITO) thin films have attracted intensive interest because of their unique properties of good conductivity, high optical transmittance over the visible region and easy patterning ability. ITO thin films have found many applications in anti-static coatings, thermal heaters, solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), electroluminescent devices, sensors and organic light-emitting diodes (OLEDs). ITO thin films are generally fabricated by using various methods, such as spraying, chemical vapor deposition (CVD), evaporation, electron gun deposition, direct current electroplating, high frequency sputtering, and reactive sputtering. In this research, ITO films were grown on glass substrates by using a radio-frequency (RF) magnetron sputtering method. In order to achieve a high transmittance and a low resistivity, we examined the various film deposition conditions, such as substrate temperature, working pressure, annealing temperature, and deposition time. Next, in order to improve the surface quality of the ITO thin films, we performed a chemical mechanical polishing (CMP) with different process parameters and compared the electrical and the optical properties of the polished ITO thin films. The best CMP conditions with a high removal rate, low nonuniformity, low resistivity and high transmittance were as follows: platen speed, head speed, polishing time, and slurry flow rate of 30 rpm, 30 rpm, 60 sec, and 60 ml/min, respectively.

  18. Fast anodization fabrication of AAO and barrier perforation process on ITO glass

    NASA Astrophysics Data System (ADS)

    Liu, Sida; Xiong, Zuzhou; Zhu, Changqing; Li, Ma; Zheng, Maojun; Shen, Wenzhong

    2014-04-01

    Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates.

  19. Free-standing GaAs nanowires growth on ITO glass by MOCVD

    NASA Astrophysics Data System (ADS)

    Wu, D.; Tang, X. H.; Olivier, A.; Li, X. Q.

    2015-04-01

    GaAs nanowires (NWs) are directly grown on indium tin oxide (ITO) glass substrate by metalorganic chemical vapour deposition (MOCVD), using Au nanoparticles (NPs) as catalyst. By functionalization of the ITO glass and optimization of the Au NPs deposition time, the Au NPs area density deposited on the ITO glass reaches 92 NP μm-2. Uniform and free-standing GaAs NWs without kinking or worm-shape defects have been grown at 430 °C. More than 96% of the NWs have tilt angles larger than 45° with respect of the substrate. The effects of the growth temperature and the Au NPs size on the GaAs NWs growth rate, the NW diameter, and tapering effect are investigated. These results of GaAs NWs growth are the essential step for understanding III-V NWs integration on transparent conductive oxide coated low cost substrate and developing high efficiencyhybrid solar cells.

  20. Fast anodization fabrication of AAO and barrier perforation process on ITO glass.

    PubMed

    Liu, Sida; Xiong, Zuzhou; Zhu, Changqing; Li, Ma; Zheng, Maojun; Shen, Wenzhong

    2014-01-01

    Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates. PMID:24708829

  1. Fast anodization fabrication of AAO and barrier perforation process on ITO glass

    PubMed Central

    2014-01-01

    Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates. PMID:24708829

  2. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Joong; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok; Kim, Han-Ki

    2015-10-01

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  3. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    SciTech Connect

    Kim, Hyo-Joong; Kim, Han-Ki; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok

    2015-10-15

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  4. Pulsed modification of germanium films on silicon, sapphire, and quartz substrates: Structure and optical properties

    SciTech Connect

    Novikov, H. A.; Batalov, R. I. Bayazitov, R. M.; Faizrakhmanov, I. A.; Lyadov, N. M.; Shustov, V. A.; Galkin, K. N.; Galkin, N. G.; Chernev, I. M.; Ivlev, G. D.; Prokop’ev, S. L.; Gaiduk, P. I.

    2015-06-15

    The structural and optical properties of thin Ge films deposited onto semiconducting and insulating substrates and modified by pulsed laser radiation are studied. The films are deposited by the sputtering of a Ge target with a low-energy Xe{sup +} ion beam. Crystallization of the films is conducted by their exposure to nanosecond ruby laser radiation pulses (λ = 0.694 μm) with the energy density W = 0.2−1.4 J cm{sup −2}. During pulsed laser treatment, the irradiated area is probed with quasi-cw (quasi-continuous-wave) laser radiation (λ = 0.532 and 1.064 μm), with the reflectance recorded R(t). Experimental data on the lifetime of the Ge melt are compared with the results of calculation, and good agreement between them is demonstrated. Through the use of a number of techniques, the dependences of the composition of the films, their crystal structure, the level of strains, and the reflectance and transmittance on the conditions of deposition and annealing are established.

  5. Modification of the substrate specificity of an acyl-acyl carrier protein thioesterase by protein engineering.

    PubMed

    Yuan, L; Voelker, T A; Hawkins, D J

    1995-11-01

    The plant acyl-acyl carrier protein (ACP) thioesterases (TEs) are of biochemical interest because of their roles in fatty acid synthesis and their utilities in the bioengineering of plant seed oils. When the FatB1 cDNA encoding a 12:0-ACP TE (Uc FatB1) from California bay, Umbellularia californica (Uc) was expressed in Escherichia coli and in developing oilseeds of the plants Arabidopsis thaliana and Brassica napus, large amounts of laurate (12:0) and small amounts of myristate (14:0) were accumulated. We have isolated a TE cDNA from camphor (Cinnamomum camphorum) (Cc) seeds that shares 92% amino acid identity with Uc FatB1. This TE, Cc FatB1, mainly hydrolyzes 14:0-ACP as shown by E. coli expression. We have investigated the roles of the N- and C-terminal regions in determining substrate specificity by constructing two chimeric enzymes, in which the N-terminal portion of one protein is fused to the C-terminal portion of the other. Our results show that the C-terminal two-thirds of the protein is critical for the specificity. By site-directed mutagenesis, we have replaced several amino acids in Uc FatB1 by using the Cc FatB1 sequence as a guide. A double mutant, which changes Met-197 to an Arg and Arg-199 to a His (M197R/R199H), turns Uc FatB1 into a 12:0/14:0 TE with equal preference for both substrates. Another mutation, T231K, by itself does not effect the specificity. However, when it is combined with the double mutant to generate a triple mutant (M197R/R199H/T231K), Uc FatB1 is converted to a 14:0-ACP TE. Expression of the double-mutant cDNA in E. coli K27, a strain deficient in fatty acid degradation, results in accumulation of similar amounts of 12:0 and 14:0. Meanwhile the E. coli expressing the triple-mutant cDNA produces predominantly 14:0 with very small amounts of 12:0. Kinetic studies indicate that both wild-type Uc FatB1 and the triple mutant have similar values of Km,app with respect to 14:0-ACP. Inhibitory studies also show that 12:0-ACP is a good

  6. Low temperature and self catalytic growth of ultrafine ITO nanowires by electron beam evaporation method and their optical and electrical properties

    SciTech Connect

    Kumar, R. Rakesh; Rao, K. Narasimha; Rajanna, K.; Phani, A.R.

    2014-04-01

    Highlights: • ITO nanowires were grown by e-beam evaporation method. • ITO nanowires growth done at low substrate temperature of 350 °C. • Nanowires growth was carried out without use of catalyst and reactive oxygen gas. • Nanowires growth proceeds via self catalytic VLS growth. • Grown nanowires have diameter 10–20 nm and length 1–4 μm long. • ITO nanowire films have shown good antireflection property. - Abstract: We report the self catalytic growth of Sn-doped indium oxide (ITO) nanowires (NWs) over a large area glass and silicon substrates by electron beam evaporation method at low substrate temperatures of 250–400 °C. The ITO NWs growth was carried out without using an additional reactive oxygen gas and a metal catalyst particle. Ultrafine diameter (∼10–15 nm) and micron long ITO NWs growth was observed in a temperature window of 300–400 °C. Transmission electron microscope studies confirmed single crystalline nature of the NWs and energy dispersive spectroscopy studies on the NWs confirmed that the NWs growth proceeds via self catalytic vapor-liquid-solid (VLS) growth mechanism. ITO nanowire films grown on glass substrates at a substrate temperature of 300–400 °C have shown ∼2–6% reflection and ∼70–85% transmission in the visible region. Effect of deposition parameters was systematically investigated. The large area growth of ITO nanowire films would find potential applications in the optoelectronic devices.

  7. A simple two-step method to fabricate highly transparent ITO/polymer nanocomposite films

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Zeng, Xiaofei; Kong, Xiangrong; Bian, Shuguang; Chen, Jianfeng

    2012-09-01

    Transparent functional indium tin oxide (ITO)/polymer nanocomposite films were fabricated via a simple approach with two steps. Firstly, the functional monodisperse ITO nanoparticles were synthesized via a facile nonaqueous solvothermal method using bifunctional chemical agent (N-methyl-pyrrolidone, NMP) as the reaction solvent and surface modifier. Secondly, the ITO/acrylics polyurethane (PUA) nanocomposite films were fabricated by a simple sol-solution mixing method without any further surface modification step as often employed traditionally. Flower-like ITO nanoclusters with about 45 nm in diameter were mono-dispersed in ethyl acetate and each nanocluster was assembled by nearly spherical nanoparticles with primary size of 7-9 nm in diameter. The ITO nanoclusters exhibited an excellent dispersibility in polymer matrix of PUA, remaining their original size without any further agglomeration. When the loading content of ITO nanoclusters reached to 5 wt%, the transparent functional nanocomposite film featured a high transparency more than 85% in the visible light region (at 550 nm), meanwhile cutting off near-infrared radiation about 50% at 1500 nm and blocking UV ray about 45% at 350 nm. It could be potential for transparent functional coating materials applications.

  8. Catalytic wateroxidation on derivatized nanoITO

    SciTech Connect

    Chen, Zuofeng; Concepcion, Javier J; Hull, Jonathan F; Hoertz, Paul G.; Meyer, Thomas J.

    2010-06-22

    Electrocatalytic water oxidation occurs on high surface area, nanocrystalline ITO (nanoITO) surface-derivatized by phosphonate-binding of the catalyst [Ru(Mebimpy)(4,4'-((HO)2OPCH2)2bpy)(OH2)]2+ (Mebimpy is 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; bpy is 2,2'-bipyridine). With nanoITO, spectral data can be acquired on electrochemically generated intermediates and voltammograms monitored spectrophotometrically.

  9. Nanopillar ITO electrodes via argon plasma etching

    SciTech Connect

    Van Dijken, Jaron G.; Brett, Michael J.

    2012-07-15

    The authors demonstrate the formation of vertically aligned indium tin oxide (ITO) nanopillars by exposing planar ITO films to Ar plasma, the conditions of which determine the size, spacing, and aspect ratio of the pillars. Annealing in air and forming gas is used to recover and optimize the optical transmittance and electrical conductivity of the nanopillar films. The final product is an ITO film whose superior optical transmittance and strong electrical conductivity combine with its robust columnar morphology and processing scalability to make it suitable for use in highly absorbing organic solar cells.

  10. Photoelectrochemical properties of ITO-coated n-type semiconductor electrodes

    NASA Astrophysics Data System (ADS)

    Kraft, Alexander; Heckner, Karl H.

    1994-09-01

    Because of their high theoretical conversion efficiencies, narrow band gap semiconductors (e.g. Si, GaAs, InP) are most suitable for photoelectrochemical solar energy conversion. unfortunately, they are destroyed by anodic dissolution (photocorrosion) in aqueous electrolytes parallel to photooxidation of electrolyte components. The coating of the semiconductor by a transparent, conductive film is one possibility for corrosion protection. We investigated the suitability of indium tin oxide (ITO) films deposited by different sputter techniques onto n-silicon and n-gallium arsenide substrates. First, the influence of the preparation conditions and of the post deposition annealing treatment on the photovoltaic properties is discussed. Second, the photoelectrochemical properties of the n- semiconductor/ITO electrodes in different aqueous electrolytes containing different redox systems are investigated. n-Si/ITO samples produced by the reactive magetron sputtering technique show the expected corrosion protection behavior, especially in electrolytes with reversible redox systems (e.g. Fe(CN)63-/4-). ITO films deposited by different sputter techniques (reactive magnetron sputtering, d.c. sputtering in different atmospheres) onto n-GaAs are not suitable for corrosion protection purposes. The low Schottky barrier at the n-GaAs/ITO interface and pinholes in the ITO layer are responsible for this behavior. The differences in photoelectrical and photoelectrochemical behavior and in corrosion stability are discussed.

  11. Switchable Super-Hydrophilic/Hydrophobic Indium Tin Oxide (ITO) Film Surfaces on Reactive Ion Etching (RIE) Textured Si Wafer.

    PubMed

    Kim, Hwa-Min; Litao, Yao; Kim, Bonghwan

    2015-11-01

    We have developed a surface texturing process for pyramidal surface features along with an indium tin oxide (ITO) coating process to fabricate super-hydrophilic conductive surfaces. The contact angle of a water droplet was less than 5 degrees, which means that an extremely high wettability is achievable on super-hydrophilic surfaces. We have also fabricated a super-hydrophobic conductive surface using an additional coating of polytetrafluoroethylene (PTFE) on the ITO layer coated on the textured Si surface; the ITO and PTFE films were deposited by using a conventional sputtering method. We found that a super-hydrophilic conductive surface is produced by ITO coated on the pyramidal Si surface (ITO/Si), with contact angles of approximately 0 degrees and a resistivity of 3 x 10(-4) Ω x cm. These values are highly dependent on the substrate temperature during the sputtering process. We also found that the super-hydrophobic conductive surface produced by the additional coating of PTFE on the pyramidal Si surface with an ITO layer (PTFE/ITO/Si) has a contact angle of almost 160 degrees and a resistivity of 3 x 10(-4) Ω x cm, with a reflectance lower than 9%. Therefore, these processes can be used to fabricate multifunctional features of ITO films for switchable super-hydrophilic and super-hydrophobic surfaces. PMID:26726545

  12. Super Smooth Modification of Al2O3 Ceramic Substrate by High Temperature Glaze of CaO-Al2O3-SiO2 System

    NASA Astrophysics Data System (ADS)

    Zhang, Jihua; Zhen, Shanxue; Yang, Lijun; Lou, Feizhi; Chen, Hongwei; Yang, Chuanren

    2011-01-01

    The rough surface of ceramic substrate is an obstacle for the scale down of line-width for thin film passive integrated devices (PID). In this paper, a modification method for Al2O3 ceramic substrate with super smooth in surface was proposed. Coating a layer of CaO-Al2O3-SiO2 (CAS) glass was performed to flat the rough surface of alumina substrate by sol-gel method. It was found that addition of 0.06% V2O5 can inhibit the recrystallization of the glaze. The root-mean-square (RMS) roughness of the glazed substrates reached a surprising flatness as small as 0.5 nm, and its melting temperature is higher than 1300 °C. This substrate with super flatness and high temperature endurance may be promising for high performance thin film devices.

  13. Roll-to-roll cohesive, coated, flexible, high-efficiency polymer light-emitting diodes utilizing ITO-free polymer anodes.

    PubMed

    Shin, Seongbeom; Yang, Minyang; Guo, L Jay; Youn, Hongseok

    2013-12-01

    This paper reports solution-processed, high-efficiency polymer light-emitting diodes fabricated by a new type of roll-to-roll coating method under ambient air conditions. A noble roll-to-roll cohesive coating system utilizes only natural gravity and the surface tension of the solution to flow out from the capillary to the surface of the substrate. Because this mechanism uses a minimally cohesive solution, the roll-to-roll cohesive coating can effectively realize an ultra-thin film thickness for the electron injection layer. In addition, the roll-to-roll cohesive coating enables the fabrication of a thicker polymer anode film more than 250 nm at one time by modification of the surface energy and without wasting the solution. It is observed that the standard sheet resistance deviation of the polymer anode is only 2.32 Ω/□ over 50 000 bending cycles. The standard sheet resistance deviation of the polymer anode in the different bending angles (0 to 180°) is 0.313 Ω/□, but the case of the ITO-PET is 104.93 Ω/□. The average surface roughness of the polymer anode measured by atomic force microscopy is only 1.06 nm. Because the surface of the polymer anode has a better quality, the leakage current of the polymer light-emitting diodes (PLEDs) using the polymer anode is much lower than that using the ITO-PET substrate. The luminous power efficiency of the two devices is 4.13 lm/W for the polymer anode and 3.21 lm/W for the ITO-PET. Consequently, the PLEDs made by using the polymer anode exhibited 28% enhanced performance because the polymer anode represents not only a higher transparency than the ITO-PET in the wavelength of 560 nm but also greatly reduced roughness. The optimized the maximum current efficiency and power efficiency of the device show around 6.1 cd/A and 5.1 lm/W, respectively, which is comparable to the case of using the ITO-glass. PMID:23784859

  14. [Coating modification of anthracite substrates in vertical-flow constructed wetlands by LDHs synthesized from different metal compounds and the nitrogen removal efficiencies].

    PubMed

    Zhang, Xiang-Ling; Guo, Lu; Chen, Jun-Jie; Liu, Xiao-Ting; Xu, Lu; Chen, Qiao-Zhen; Wang, Xiao-Xiao

    2014-08-01

    As one kind of vertical-flow constructed wetlands substrates, anthracite was selected in this experiment. LDHs (layered double hydroxides) were synthesized in alkaline conditions by co-precipitation of different kinds of metal compounds, such as CaCl2, ZnCl2, MgCl2, FeCl3, AlCl3, CoCl3. The synthesized LDHs were in-situ coated onto the surface of anthracite substrate to achieve the aim of modification. Simulated test columns were constructed to study the nitrogen removal efficiency of the urban sewage using the original anthracite substrates and 9 kinds of modified anthracite substrates. The results showed that: LDHs synthesized by all the 9 different kinds of methods could effectively modify the anthracite substrate by in-situ coating. With Mg2+ involved in the synthesis of modified substrates, good TN and ammonia nitrogen removal efficiencies were observed. The modified anthracite substrates coated with MgCo-LDHs had the optimal performance with average TN and ammonia nitrogen removal efficiencies of higher than 80% and 85%, respectively. The ammonia nitrogen removal efficiencies by the modified anthracite substrates coated by LDHs reacted with Mg2+ and Fe3+ were also high. The ammonia nitrogen removal efficiencies by modified anthracite substrates coated with CaFe-LDHs and MgFe-LDHs were higher than 85%. PMID:25340214

  15. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    NASA Astrophysics Data System (ADS)

    Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

    2014-04-01

    The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

  16. Highly transparent ITO thin films on photosensitive glass: sol-gel synthesis, structure, morphology and optical properties

    NASA Astrophysics Data System (ADS)

    Kőrösi, László; Papp, Szilvia; Beke, Szabolcs; Pécz, Béla; Horváth, Róbert; Petrik, Péter; Agócs, Emil; Dékány, Imre

    2012-05-01

    Conductive and highly transparent indium tin oxide (ITO) thin films were prepared on photosensitive glass substrates by the combination of sol-gel and spin-coating techniques. First, the substrates were coated with amorphous Sn-doped indium hydroxide, and these amorphous films were then calcined at 550∘C to produce crystalline and electrically conductive ITO layers. The resulting thin films were characterized by means of scanning electron microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The measurements revealed that the ITO films were composed of spherical crystallites around 20 nm in size with mainly cubic crystal structure. The ITO films acted as antireflection coatings increasing the transparency of the coated substrates compared to that of the bare supports. The developed ITO films with a thickness of ˜170-330 nm were highly transparent in the visible spectrum with sheet resistances of 4.0-13.7 kΩ/sq. By coating photosensitive glass with ITO films, our results open up new perspectives in micro- and nano-technology, for example in fabricating conductive and highly transparent 3D microreactors.

  17. Influence of substrate modification and C-terminal truncation on the active site structure of substrate-bound heme oxygenase from Neisseriae meningitidis; A 1H NMR study†

    PubMed Central

    Peng, Dungeng; Satterlee, James D.; Ma, Li-Hua; Dallas, Jerry L.; Smith, Kevin M.; Zhang, Xuhong; Sato, Michihiko; La Mar, Gerd N.

    2011-01-01

    Heme oxygenase, HO, from the pathogenic bacterium N. meningitidis, NmHO, which secures host iron, shares many properties with mammalian HOs, but also exhibits some key differences. The crystal structure appears more compact and the crystal-undetected C-terminus interacts with substrate in solution. The unique nature of substrate-protein, specifically pyrrole-I/II-helix-2, peripheral interactions in NmHO are probed by 2D 1H NMR to reveal unique structural features controlling substrate orientation. The thermodynamics of substrate orientational isomerism are mapped for substrates with individual vinyl → methyl → hydrogen substitutions and with enzyme C-terminal deletions. NmHO exhibits significantly stronger orientational preference, reflecting much stronger and selective pyrrole-I/II interactions with the protein matrix, than in mammalian HOs. Thus, replacing bulky vinyls with hydrogens results in a 180° rotation of substrate about the α,γ-meso axis in the active site. A "collapse" of the substrate pocket as substrate size decreases is reflected in movement of helix-2 toward the substrate as indicated by significant and selective increased NOESY cross peak intensity, increase in steric Fe-CN tilt reflected in the orientation of the major magnetic axis, and decrease in steric constraints controlling the rate of aromatic ring reorientation. The active site of NmHO appears "stressed" for native protohemin and its "collapse" upon replacing vinyls by hydrogen leads to a factor ~102 increase in substrate affinity. Interaction of the C-terminus with the active site destabilizes the crystallographic protohemin orientation by ~0.7 kcal/mol, which is consistent with optimizing the His207-Asp27 H-bond. Implications of the active site "stress" for product release are discussed. PMID:21870860

  18. DbPTM 3.0: an informative resource for investigating substrate site specificity and functional association of protein post-translational modifications.

    PubMed

    Lu, Cheng-Tsung; Huang, Kai-Yao; Su, Min-Gang; Lee, Tzong-Yi; Bretaña, Neil Arvin; Chang, Wen-Chi; Chen, Yi-Ju; Chen, Yu-Ju; Huang, Hsien-Da

    2013-01-01

    Protein modification is an extremely important post-translational regulation that adjusts the physical and chemical properties, conformation, stability and activity of a protein; thus altering protein function. Due to the high throughput of mass spectrometry (MS)-based methods in identifying site-specific post-translational modifications (PTMs), dbPTM (http://dbPTM.mbc.nctu.edu.tw/) is updated to integrate experimental PTMs obtained from public resources as well as manually curated MS/MS peptides associated with PTMs from research articles. Version 3.0 of dbPTM aims to be an informative resource for investigating the substrate specificity of PTM sites and functional association of PTMs between substrates and their interacting proteins. In order to investigate the substrate specificity for modification sites, a newly developed statistical method has been applied to identify the significant substrate motifs for each type of PTMs containing sufficient experimental data. According to the data statistics in dbPTM, >60% of PTM sites are located in the functional domains of proteins. It is known that most PTMs can create binding sites for specific protein-interaction domains that work together for cellular function. Thus, this update integrates protein-protein interaction and domain-domain interaction to determine the functional association of PTM sites located in protein-interacting domains. Additionally, the information of structural topologies on transmembrane (TM) proteins is integrated in dbPTM in order to delineate the structural correlation between the reported PTM sites and TM topologies. To facilitate the investigation of PTMs on TM proteins, the PTM substrate sites and the structural topology are graphically represented. Also, literature information related to PTMs, orthologous conservations and substrate motifs of PTMs are also provided in the resource. Finally, this version features an improved web interface to facilitate convenient access to the resource

  19. Structural and optical properties of ITO/TiO2 anti-reflective films for solar cell applications.

    PubMed

    Ali, Khuram; Khan, Sohail A; Jafri, Mohd Zubir Mat

    2014-01-01

    Indium tin oxide (ITO) and titanium dioxide (TiO2) anti-reflective coatings (ARCs) were deposited on a (100) P-type monocrystalline Si substrate by a radio-frequency (RF) magnetron sputtering. Polycrystalline ITO and anatase TiO2 films were obtained at room temperature (RT). The thickness of ITO (60 to 64 nm) and TiO2 (55 to 60 nm) films was optimized, considering the optical response in the 400- to 1,000-nm wavelength range. The deposited films were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and atomic force microscopy (AFM). The XRD analysis showed preferential orientation along (211) and (222) for ITO and (200) and (211) for TiO2 films. The XRD analysis showed that crystalline ITO/TiO2 films could be formed at RT. The crystallite strain measurements showed compressive strain for ITO and TiO2 films. The measured average optical reflectance was about 12% and 10% for the ITO and TiO2 ARCs, respectively. PMID:24721986

  20. Physical properties of ITO thin films prepared by ion-assisted electron beam evaporation

    NASA Astrophysics Data System (ADS)

    Qiu, Yang; Jin, Yangli; Zhao, Hua; Xu, Bo; Wang, Jiajia

    2014-12-01

    Tin doped indium oxide (ITO) thin films were prepared on IR glass substrates at different oxygen flow rate by ion-assisted electron beam evaporation method. Properties such as microstructure, morphology, sheet resistance and optical transmittance were investigated by X-ray diffractometer, SEM, four-point probe and UV-VIS-IR spectrophotometer, respectively. Lattice constant, inner stress level and energy band gap (Eg) of ITO thin films as-deposited were calculated and discussed. The mechanical properties of ITO thin films were studied by scratching method. The measurements were performed by scratch tester and the results were recorded as acoustic emission spectra and scratch track images taken by SEM. Relationship between inner stress level and mechanical performance was investigated in detail.

  1. A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals.

    PubMed

    Sangeetha, N M; Gauvin, M; Decorde, N; Delpech, F; Fazzini, P F; Viallet, B; Viau, G; Grisolia, J; Ressier, L

    2015-08-01

    Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn(4+) doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, (1)H, (13)C and (119)Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 10(3) for oleate ITO to 13 × 10(3)Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry. PMID:26150112

  2. Electrodeposition of gold nanoparticle arrays on ITO glass as electrode with high electrocatalytic activity

    SciTech Connect

    Zhang, Kui; Wei, Juan; Zhu, Houjuan; Ma, Fang; Wang, Suhua

    2013-03-15

    Highlights: ► Electrodeposition of gold nanoparticle arrays on ITO glass as catalytic-electrodes. ► The sizes and densities of the gold nanoparticles can be easily controlled. ► Such arrays on ITO glass shows high electrocatalytic activity and good stability. - Abstract: Herein, we reported a templateless, surfactantless, and simple electrochemical method to directly fabricate gold nanoparticle (AuNP) arrays on indium tin oxide (ITO) glass substrates as effective electrocatalytic electrodes. The as-prepared AuNP arrays have been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), etc. AuNPs with small sizes (<20 nm) were uniformly deposited on the ITO glass under constant current densities, and particle densities can be adjusted by varying the applied charges. The resultant AuNP array electrode showed higher catalytic activity and good stability toward electro-oxidation of ascorbic acid compared with other electrodes, such as bare ITO electrode, bare glassy carbon electrode and bulk gold film electrode.

  3. In situ Crystallization of RF sputtered ITO thin films: A comparison with annealed samples

    SciTech Connect

    John, K. Aijo; Manju, T.

    2014-01-28

    Tin doped Indium Oxide (ITO) is a wide band gap semiconductor with high conductivity and transparency in the visible region of the solar spectrum. One of the most popular and exploited applications of ITO is the realization of the transparent conductive layers needed for the electrodes of light sensitive devices, such as photovoltaic cells. The thermal energy for the crystallization of ITO films is very low (150°C). The crystallization can be achieved by the continuous energetic bombardment of the ions in the sputtering chamber without annealing or substrate heating. The accumulated energy will ensure the thermal energy necessary for the crystallization. With the help of sufficiently high sputtering power and sufficient duration, crystallized ITO films can be produced without annealing. In this report, a comparison of the conductivity and transparency of ITO films under two crystallization conditions ((1) crystallization of the sputtered films by annealing; (2) in situ crystallization of the films by providing high sputtering power and long sputtering duration) will be presented.

  4. A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals

    NASA Astrophysics Data System (ADS)

    Sangeetha, N. M.; Gauvin, M.; Decorde, N.; Delpech, F.; Fazzini, P. F.; Viallet, B.; Viau, G.; Grisolia, J.; Ressier, L.

    2015-07-01

    Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn4+ doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, 1H, 13C and 119Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 103 for oleate ITO to 13 × 103 Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry.Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn4+ doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, 1H, 13C and 119Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 103 for

  5. Directed modification of the Aspergillus usamii β-mannanase to improve its substrate affinity by in silico design and site-directed mutagenesis.

    PubMed

    Li, Jianfang; Wei, Xihuan; Tang, Cunduo; Wang, Junqing; Zhao, Mei; Pang, Qingfeng; Wu, Minchen

    2014-04-01

    β-Mannanases (EC 3.2.1.78) can catalyze the cleavage of internal β-1,4-D-mannosidic linkages of mannan backbones, and they have found applications in food, feed, pulp and paper, oil, pharmaceutical and textile industries. Suitable amino acid substitution can promote access to the substrate-binding groove and maintain the substrate therein, which probably improves the substrate affinity and, thus, increases catalytic efficiency of the enzyme. In this study, to improve the substrate affinity of AuMan5A, a glycoside hydrolase (GH) family 5 β-mannanase from Aspergillus usamii, had its directed modification conducted by in silico design, and followed by site-directed mutagenesis. The mutant genes, Auman5A (Y111F) and Auman5A (Y115F), were constructed by megaprimer PCR, respectively. Then, Auman5A and its mutant genes were expressed in Pichia pastoris GS115 successfully. The specific activities of purified recombinant β-mannanases (reAuMan5A, reAuMan5A(Y111F) and reAuMan5A(Y115F)) towards locust bean gum were 152.5, 199.6 and 218.9 U mg(-1), respectively. The two mutants were found to be similar to reAuMan5A regarding temperature and pH characteristics. Nevertheless, the K m values of reAuMan5A(Y111F) and reAuMan5A(Y115F), towards guar gum, decreased to 2.95 ± 0.22 and 2.39 ± 0.33 mg ml(-1) from 4.49 ± 0.07 mg ml(-1) of reAuMan5A, which would make reAuMan5A(Y111F) and reAuMan5A(Y115F) promising candidates for industrial processes. Structural analysis showed that the two mutants increased their affinity by decreasing the steric conflicts with those more complicated substrates. The results suggested that subtle conformational modification in the substrate-binding groove could substantially alter the substrate affinity of AuMan5A. This study laid a solid foundation for the directed modification of substrate affinities of β-mannanases and other enzymes. PMID:24493565

  6. A Darboux Transformation for Ito Equation

    NASA Astrophysics Data System (ADS)

    Niu, Xiaoxing; Zhang, Mengxia; Lv, Shuqiang

    2016-05-01

    A system proposed by Ito is reconsidered. The corresponding Darboux transformation is presented explicitly. The resulted Bäcklund transformation is shown to be equivalent to the one found by Hirota. Also, a nonlinear superposition formula, which is of differential-algebraic, is obtained.

  7. MODIFICATION OF THE 14C MOST-PROBABLE-NUMBER METHOD FOR USE WITH NONPOLAR AND VOLATILE SUBSTRATES

    EPA Science Inventory

    A method was developed to allow the use of volatile and nonpolar substrates in (14)C most-probable-number tests. Naphthalene or hexadecane was sorbed to filter paper disks and submerged in minimal medium. The procedure reduced the volatilization of the substrates while allowing t...

  8. Initial stages of ITO/Si interface formation: In situ x-ray photoelectron spectroscopy measurements upon magnetron sputtering and atomistic modelling using density functional theory

    SciTech Connect

    Løvvik, O. M.; Diplas, S.; Ulyashin, A.; Romanyuk, A.

    2014-02-28

    Initial stages of indium tin oxide (ITO) growth on a polished Si substrate upon magnetron sputtering were studied experimentally using in-situ x-ray photoelectron spectroscopy measurements. The presence of pure indium and tin, as well as Si bonded to oxygen at the ITO/Si interface were observed. The experimental observations were compared with several atomistic models of ITO/Si interfaces. A periodic model of the ITO/Si interface was constructed, giving detailed information about the local environment at the interface. Molecular dynamics based on density functional theory was performed, showing how metal-oxygen bonds are broken on behalf of silicon-oxygen bonds. These theoretical results support and provide an explanation for the present as well as previous ex-situ and in-situ experimental observations pointing to the creation of metallic In and Sn along with the growth of SiO{sub x} at the ITO/Si interface.

  9. A novel approach for enhancing the catalytic efficiency of a protease at low temperature: reduction in substrate inhibition by chemical modification.

    PubMed

    Siddiqui, Khawar Sohail; Parkin, Don M; Curmi, Paul M G; De Francisci, Davide; Poljak, Anne; Barrow, Kevin; Noble, Malcolm H; Trewhella, Jill; Cavicchioli, Ricardo

    2009-07-01

    The alkaline protease, savinase was chemically modified to enhance the productivity of the enzyme at low temperatures on a complex polymeric protein (azocasein) substrate. At 5 and 15 degrees C, savinase modified with ficol or dextran hydrolyzed fivefold more azocasein than the unmodified savinase. Kinetic studies showed that the catalytic improvements are associated with changes in uncompetitive substrate inhibition with K(i) values of modified savinases sixfold higher than the unmodified savinase. Modeling of small-angle scattering data indicates that two substrate molecules bind on opposing sides of the enzyme. The combined kinetic and structural data indicate that the polysaccharide modifier sterically blocks the allosteric site and reduces substrate inhibition. In contrast to the properties of cold-active enzymes that generally manifest as low activation enthalpy and high flexibility, this study shows that increased activity and productivity at low temperature can be achieved by reducing uncompetitive substrate inhibition, and that this can be achieved using chemical modification with an enzyme in a commercial enzyme-formulation. PMID:19288442

  10. Effect of Aluminum Substrate Surface Modification on Wettability and Freezing Delay of Water Droplet at Subzero Temperatures.

    PubMed

    Rahimi, Maral; Afshari, Alireza; Thormann, Esben

    2016-05-01

    In this study, we have investigated the freezing delay of a water droplet on precooled substrates of an aluminum alloy that is commonly used for heat-exchanger fins. The surfaces of the substrates were modified to obtain surfaces with different hydrophilicity/hydrophobicity and different surface chemistry but without significantly modifying the surface topography. The freezing delays and water contact angles were measured as a function of the substrate temperature and the results were compared to the predictions of the heterogeneous ice nucleation theory. Although the trends for each sample followed the trend in this theory, the differences in the extents of freezing delays were in apparent disagreement with the predictions. Concretely, a slightly hydrophilic substrate modified by (3-aminopropyl) triethoxysilane (APTES) showed longer freezing delays than both more hydrophilic and more hydrophobic substrates. We suggest that this is because this particular surface chemistry prevents ice formation at the interface of the substrate, prior to the deposition of the water droplet. On the basis of our results, we suggest that not only wettability and topography but also the concrete surface chemistry plays a significant role in the kinetics of the ice formation process when a water droplet is placed on a precooled substrate. PMID:27045573

  11. Solution NMR study of environmental effects on substrate seating in human heme oxygenase: influence of polypeptide truncation, substrate modification and axial ligand.

    PubMed

    Zhu, Wenfeng; Li, Yiming; Wang, Jinling; Ortiz de Montellano, Paul R; La Mar, Gerd N

    2006-01-01

    Solution proton NMR has been used here to show that, as either the high-spin ferric, protohemin (PH) substrate complex at neutral pH, or the low-spin ferric, cyanide-inhibited PH substrate complex, the active site electronic and molecular structure of the 233- and 265-residue recombinant constructs of human heme oxygenase-1, hHO, are essentially indistinguishable. It is shown, moreover, that the equilibrium PH orientational isomerism about the alpha,gamma-meso axis is 1:1 in the water-ligated, resting-state complex, but changes to a 4:1 equilibrium ratio as the cyanide-inhibited complex, with the minor species in solution corresponding to the only one found in crystals. The introduction of significant PH orientational preference in the cyanide over the aquo complex is rationalized by the crystallographic observation for the same H2O and CN ligated complexes of rat heme oxygenase (rHO), where the steric tilt of the Fe-CN unit resulted in a approximately 1 A transition of PH into the hydrophobic interior, and stronger interaction of the vinyls with the HO matrix [M. Sugishima, H. Sakamoto, M. Noguchi, K. Fukugama, Biochemistry 42 (2003) 9898-9905]. 1H NMR spectra of the cyanide-inhibited PH complex are the most used, and most useful, for determining the distribution of orientational isomerism for PH in complexes of HO. Hence, it is imperative that the time-course of the spectra after sample preparation be considered in order to reach conclusions that relate isomeric seating of the heme with variable isomeric biliverdin products. The natural orientational isomerism of PH leads to spectral congestion that has prompted the use of a synthetic, twofold symmetric substrate, 2,4-dimethyldeuterohemin, DMDH. While the hyperfine shift pattern for non-ligated residues are very similar and are consistent with largely conserved molecular structure with the alternate substrates, the steric tilt of the Fe-CN vector towards the protein interior, as determined by the orientation of

  12. Crystallization of Tyrian purple (6,6‧-dibromoindigo) thin films: The impact of substrate surface modifications

    NASA Astrophysics Data System (ADS)

    Truger, Magdalena; Jones, Andrew O. F.; Coclite, Anna Maria; Pachmajer, Stefan; Kriegner, Dominik; Röthel, Christian; Simbrunner, Josef; Salzmann, Ingo; Resel, Roland

    2016-08-01

    The pigment 6,6‧-dibromoindigo (Tyrian purple) shows strong intermolecular hydrogen bonds and the film formation is, therefore, expected to be influenced by the polar character of the substrate surface. Thin films of Tyrian purple were prepared by physical vapor deposition on a variety of substrates with different surface energies: from highly polar silicon dioxide surfaces to hydrophobic polymer surfaces. The crystallographic properties were investigated by X-ray diffraction techniques such as X-ray reflectivity and grazing incidence X-ray diffraction. In all cases, crystallites with "standing" molecules relative to the substrate surface were observed independently of the substrate surface energy. In the case of polymer surfaces, additional crystallites are formed containing "lying" molecules with their aromatic planes parallel to the substrate surface. Small differences in the crystallographic lattice constants were observed as a function of substrate surface energy, the corresponding small changes in the molecular packing are explained by a variation of the hydrogen bond geometries. This work reveals that despite the limited influence of the surface energy on the molecular orientation, the crystalline packing of Tyrian purple within thin films is altered and slightly different structures form.

  13. Modification of the catalytic subunit of bovine heart cAMP-dependent protein kinase with affinity labels related to peptide substrates.

    PubMed

    Bramson, H N; Thomas, N; Matsueda, R; Nelson, N C; Taylor, S S; Kaiser, E T

    1982-09-25

    The modification and concomitant inactivation of the catalytic subunit of bovine heart cAMP-dependent protein kinase with affinity analogs of peptide substrates potentially capable of undergoing disulfide interchange with enzyme-bound sulfhydryl groups have been used to probe the active site associated with peptide binding. The regeneration of catalytic activity on treatment of the modified enzymes with dithiothreitol and the observation that prior reaction with 5,5'-dithiobis-(2-nitrobenzoic acid) blocks the modification of the kinase by these reagents are consistent with the proposal that only thiol residues are reacting. The affinity analog Leu-Arg-Arg-Ala-Cys(3-nitro-2-pyridinesulfenyl)-Leu-Gly, 1, and the closely related peptide AcLeu-Arg-Arg-Ala-Cys(3-nitro-2-pyridinesulfenyl)-Leu-Gly-OEt, 3, react with a single sulfhydryl as shown by the stoichiometry of the release of the 3-nitro-2-pyridinesulfenyl group and the amount of label incorporated in the enzyme when the radioactively labeled peptide analog of 3 (peptide 4) is employed as the modifying agent. The kinetics of the reaction of 1 with 4.3 microM catalytic subunit was monophasic (employing substrate in excess conditions), yielding an apparent value of KI of approximately 40 microM and a k2 value of approximately 0.25 s-1. The low value of the observed KI, together with the observation that protein kinase substrates inhibit the modification reactions, suggest strongly that the cysteine residue undergoing reaction is in the vicinity of the active site. By trypsin-catalyzed degradation and identification of the peptide segment modified by covalent attachment of the peptide portion of the radioactive analog 4, the single cysteine modified was identified as cysteine-198. PMID:6286662

  14. Investigation of ITO layers for application as transparent contacts in flexible photovoltaic cell structures

    NASA Astrophysics Data System (ADS)

    Znajdek, Katarzyna; Sibiński, Maciej

    2013-07-01

    In this paper authors present the mechanical, optical and electrical parameters of Indium Tin Oxide (ITO) Transparent Conductive Layers (TCL) deposited on flexible substrate. Layers' properties are analyzed and verified. Investigated Transparent Conductive Oxide (TCO) was deposited, using magnetron sputtering method. Flexible polymer PET (polyethylene terephthalate) foil was used as a substrate, in order to photovoltaic (PV) cell's emitter contact application of investigated material. ITO-coated PET foils have been dynamically bent on numerous cylinders of various diameters according to the standard requirements. Resistance changes for each measured sample were measured and recorded during bending cycle. Thermal durability, as well as temperature influence on resistance and optical transmission are verified. Presented results were conducted to verify practical suitability and to evaluate possible applications of Indium Tin Oxide as a front contact in flexible photovoltaic cell structures.

  15. Transparent Multi-level Resistive Switching Phenomena Observed in ITO/RGO/ITO Memory Cells by the Sol-Gel Dip-Coating Method

    PubMed Central

    Kim, Hee-Dong; Yun, Min Ju; Lee, Jae Hoon; Kim, Kyoeng Heon; Kim, Tae Geun

    2014-01-01

    A reduced graphene oxide (RGO)-based transparent electronic memory cell with multi-level resistive switching (RS) was successfully realized by a dip-coating method. Using ITO/RGO/ITO structures, the memory device exhibited a transmittance above 80% (including the substrate) in the visible region and multi-level RS behavior in the 00, 01, 10, and 11 states by varying the pulse height from 2 V to 7 V. In the reliability test, the device exhibited a good endurance of over 105 cycles and a long data retention of over 105 s at 85°C in each state. We believe that the RGO-based transparent memory presented in this work could be a milestone for future transparent electronic devices. PMID:24714566

  16. Growth and characterization of transparent Pb(Zi, Ti)O{sub 3} capacitor on glass substrate.

    SciTech Connect

    Uprety, K. K.; Ocola, L. E.; Auciello, O.

    2007-10-15

    (Pb)(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) films were fabricated on LaNiO{sub 3} (LNO)/In{sub 2}O{sub 3} 90%SnO{sub 2}10% (ITO) layered transparent electrodes on glass substrates using chemical solution deposition. The structural, electrical, and optical properties of semitransparent Pd/PZT/LNO/ITO and transparent ITO/LNO/PZT/LNO/ITO capacitors fabricated on glass substrates were studied. X-ray diffraction revealed an improved crystalline structure of PZT on ITO-buffered glass substrates by interposing a LNO layer between PZT and ITO. Atomic force microscopy showed a smoother surface topography for the LNO/ITO layered electrode on glass, as compared to that of the single ITO layer on glass. The remnant polarization (P{sub r}) of the Pd/PZT/LNO/ITO/glass capacitors and transparent ITO/LNO/PZT/LNO/ITO/glass capacitors was estimated from P-E hysteresis loops. The Pd/PZT/LNO/ITO capacitors on glass revealed significant improvement in the P{sub r} as compared to PZT film based capacitors with ITO electrodes only. Excellent optical transmittance was observed for the whole capacitor structure. The importance of a high performance transparent capacitor is that this structure may enable high efficiency transparent electronic devices such as solar energy storage, photovoltaic, and intelligent windows, among others.

  17. c-Myc alters substrate utilization and O-GlcNAc protein posttranslational modifications without altering cardiac function during early aortic constriction

    SciTech Connect

    Ledee, Dolena; Smith, Lincoln; Bruce, Margaret; Kajimoto, Masaki; Isern, Nancy; Portman, Michael A.; Olson, Aaron K.; Bertrand, Luc

    2015-08-12

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (TAC; n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (predominately glucose) contribution. The changes in free fatty acid and unlabeled fractional contributions were abrogated by Myc inactivation during TAC (MycKO-TAC). Additionally, protein posttranslational modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. Lastly, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy.

  18. c-Myc alters substrate utilization and O-GlcNAc protein posttranslational modifications without altering cardiac function during early aortic constriction

    DOE PAGESBeta

    Ledee, Dolena; Smith, Lincoln; Bruce, Margaret; Kajimoto, Masaki; Isern, Nancy; Portman, Michael A.; Olson, Aaron K.; Bertrand, Luc

    2015-08-12

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (TAC; n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated workingmore » hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (predominately glucose) contribution. The changes in free fatty acid and unlabeled fractional contributions were abrogated by Myc inactivation during TAC (MycKO-TAC). Additionally, protein posttranslational modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. Lastly, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy.« less

  19. 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.

  20. Modification of fluorous substrates with oligo(ethylene glycol) via "click" chemistry for long-term resistance of cell adhesion.

    PubMed

    Contreras-Caceres, Rafael; Santos, Catherine M; Li, Siheng; Kumar, Amit; Zhu, Zhiling; Kolar, Satya S; Casado-Rodriguez, Miguel A; Huang, Yongkai; McDermott, Alison; Lopez-Romero, Juan Manuel; Cai, Chengzhi

    2015-11-15

    In this work perfluorinated substrates fabricated from SiO2 glass slides are modified with oligo(ethylene glycol) (OEG) units for long-term resistance of cell adhesion purposes, based on fluorous interactions and click chemistry. Specifically, fluorous substrates, prepared by treatment of glass slides with 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane (FAS17), were coated with ethynyl-OEG-C8F17, followed by covalent attachment of an azido-OEG via copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction. We demonstrate that the resultant surface avoid fibrinogen adsorption and resisted cell adhesion for over 14days. X-ray photoemission spectroscopy (XPS) analysis and contact angle goniometry measurements confirm the presence of the OEG molecules on the fluorous substrates. Bright field optical images show total absence of 3T3 fibroblast cells on the OEG modified fluorinated substrate for 1 and 5days, and a remarkably decrease of cell adhesion at 14days. PMID:26210101

  1. Modification of PATase by L/F-transferase generates a ClpS-dependent N-end rule substrate in Escherichia coli

    PubMed Central

    Ninnis, Robert L; Spall, Sukhdeep K; Talbo, Gert H; Truscott, Kaye N; Dougan, David A

    2009-01-01

    The N-end rule pathway is conserved from bacteria to man and determines the half-life of a protein based on its N-terminal amino acid. In Escherichia coli, model substrates bearing an N-degron are recognised by ClpS and degraded by ClpAP in an ATP-dependent manner. Here, we report the isolation of 23 ClpS-interacting proteins from E. coli. Our data show that at least one of these interacting proteins—putrescine aminotransferase (PATase)—is post-translationally modified to generate a primary N-degron. Remarkably, the N-terminal modification of PATase is generated by a new specificity of leucyl/phenylalanyl-tRNA-protein transferase (LFTR), in which various combinations of primary destabilising residues (Leu and Phe) are attached to the N-terminal Met. This modification (of PATase), by LFTR, is essential not only for its recognition by ClpS, but also determines the stability of the protein in vivo. Thus, the N-end rule pathway, through the ClpAPS-mediated turnover of PATase may have an important function in putrescine homeostasis. In addition, we have identified a new element within the N-degron, which is required for substrate delivery to ClpA. PMID:19440203

  2. ITOS D AND E system design report, volume 1

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The configuration and functions of the ITOS D and E system are described. The system will expand the operational capability of the basic TIROS M/ITOS system. The ITOS D and E mission will utilize the capabilities of the two-stage DSV 3N-6 Delta launch vehicle to place the ITOS D and E spacecraft into a circular, near-polar, sun synchronous orbit at 790 nautical miles altitude. The ITOS D and E will provide the following primary data: (1) visible daytime observations of cloud cover, (2) daytime and nighttime observations of cloud cover as detected from radiance in infrared spectrum, and (3) vertical temperature profile of the atmosphere on a global basis for data processing. In addition, the ITOS D and E system will provide secondary data comprising solar proton density measurements obtained throughout the orbit.

  3. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras.

    PubMed

    Warren, Jeremy G; Lincoln, James E; Kirkpatrick, Bruce C

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  4. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras

    PubMed Central

    Warren, Jeremy G.; Lincoln, James E.; Kirkpatrick, Bruce C.

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  5. Probing the promiscuous active site of myo-inositol dehydrogenase using synthetic substrates, homology modeling, and active site modification.

    PubMed

    Daniellou, Richard; Zheng, Hongyan; Langill, David M; Sanders, David A R; Palmer, David R J

    2007-06-26

    The active site of myo-inositol dehydrogenase (IDH, EC 1.1.1.18) from Bacillus subtilis recognizes a variety of mono- and disaccharides, as well as 1l-4-O-substituted inositol derivatives. It catalyzes the NAD+-dependent oxidation of the axial alcohol of these substrates with comparable kinetic constants. We have found that 4-O-p-toluenesulfonyl-myo-inositol does not act as a substrate for IDH, in contrast to structurally similar compounds such as those bearing substituted benzyl substituents in the same position. X-ray crystallographic analysis of 4-O-p-toluenesulfonyl-myo-inositol and 4-O-(2-naphthyl)methyl-myo-inositol, which is a substrate for IDH, shows a distinct difference in the preferred conformation of the aryl substituent. Conformational analysis of known substrates of IDH suggests that this conformational difference may account for the difference in reactivity of 4-O-p-toluenesulfonyl-myo-inositol in the presence of IDH. A sequence alignment of IDH with the homologous glucose-fructose oxidoreductase allowed the construction of an homology model of inositol dehydrogenase, to which NADH and 4-O-benzyl-scyllo-inosose were docked and the active site energy minimized. The active site model is consistent with all experimental results and suggests that a conserved tyrosine-glycine-tyrosine motif forms the hydrophobic pocket adjoining the site of inositol recognition. Y233F and Y235F retain activity, while Y233R and Y235R do not. A histidine-aspartate pair, H176 and D172, are proposed to act as a dyad in which H176 is the active site acid/base. The enzyme is inactivated by diethyl pyrocarbonate, and the mutants H176A and D172N show a marked loss of activity. Kinetic isotope effect experiments with D172N indicate that chemistry is rate-determining for this mutant. PMID:17539607

  6. Surface modification of titanium substrates with silver nanoparticles embedded sulfhydrylated chitosan/gelatin polyelectrolyte multilayer films for antibacterial application.

    PubMed

    Li, Wen; Xu, Dawei; Hu, Yan; Cai, Kaiyong; Lin, Yingcheng

    2014-06-01

    To develop Ti implants with potent antibacterial activity, a novel "sandwich-type" structure of sulfhydrylated chitosan (Chi-SH)/gelatin (Gel) polyelectrolyte multilayer films embedding silver (Ag) nanoparticles was coated onto titanium substrate using a spin-assisted layer-by-layer assembly technique. Ag ions would be enriched in the polyelectrolyte multilayer films via the specific interactions between Ag ions and -HS groups in Chi-HS, thus leading to the formation of Ag nanoparticles in situ by photo-catalytic reaction (ultraviolet irradiation). Contact angle measurement and field emission scanning electron microscopy equipped with energy dispersive X-ray spectroscopy were employed to monitor the construction of Ag-containing multilayer on titanium surface, respectively. The functional multilayered films on titanium substrate [Ti/PEI/(Gel/Chi-SH/Ag) n /Gel] could efficiently inhibit the growth and activity of Bacillus subtitles and Escherichia coli onto titanium surface. Moreover, studies in vitro confirmed that Ti substrates coating with functional multilayer films remained the biological functions of osteoblasts, which was reflected by cell morphology, cell viability and ALP activity measurements. This study provides a simple, versatile and generalized methodology to design functional titanium implants with good cyto-compatibility and antibacterial activity for potential clinical applications. PMID:24664672

  7. Modification of the surface layer of the system coating (TiCuN)/substrate (A7) by an intensive electron beam

    NASA Astrophysics Data System (ADS)

    Ivanov, Yu F.; Potekaev, A. I.; Petrikova, E. A.; Ivanova, O. V.; Ikonnikova, I. A.; Shugurov, V. V.; Krysina, O. V.; Klopotov, A. A.

    2015-04-01

    In order to study the conditions of modification of the surface layer of the system coating (TiCuN)/substrate (A7) an analysis of processes occurring in the surface layer of the system wear-resistant coating/substrate irradiated by an intensive pulsed electron beam at a submillisecond exposure time has been carried out on the example of aluminum and titanium nitride. Irradiation has been carried out under conditions ensuring melting and crystallization of the surface layer of the material by a nonequilibrium phase diagram. It has been experimentally established that irradiation of the system coating (TiCuN)/substrate (A7) by an intensive electron beam is accompanied by changes in the phase composition of the material. It is evident that nanostructuring of the aluminum layer adjacent to the coating, and formation in it of nitride phase particles will contribute to hardening of the surface layer of the material, creating a transition sublayer between a solid coating and a relatively soft volume. The carried out analysis shows that binary nitrides based on TiN1-x are most likely to form under nonequilibrium conditions, since the homogeneity range of this compound is rather large. On the other hand, formation of the ternary compound Ti3CuN, which can be formed after an arc plasma-assisted deposition of titanium nitride of the composition TiCuN and by the subsequent intensive pulsed electron beam exposure, cannot be excluded.

  8. ITO/metal/ITO anode for efficient transparent white organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Joo, Chul Woong; Lee, Jonghee; Sung, Woo Jin; Moon, Jaehyun; Cho, Nam Sung; Chu, Hye Yong; Lee, Jeong-Ik

    2015-02-01

    We report on the characteristics of enhanced and balanced white-light emission of transparent organic light emitting diodes (TOLEDs) by introducing anode that has a stack structure of ITO/metal/ITO (IMI). We have investigated an anode that has a stack structure of IMI. IMI anodes are typically composed of a thin Ag layer (˜15 nm) sandwiched between two ITO layers (˜50 nm). By inserting an Ag layer it was possible to achieve sheet resistance lower than 3 Ω/sq. and transmittance of 86% at a wavelength of 550 nm. The Ag insert can act as a reflective component. With its counterpart, a transparent cathode made of a thin Ag layer (˜15 nm), micro-cavities (MC) can be effectively induced in the OLED, leading to improved performance. Using an IMI anode, it was possible to significantly increase the current efficiencies. The current efficiencies of the top and the bottom of the IMI TOLED increased to 23.0 and 15.6 cd/A, respectively, while those of the white TOLED with the ITO anode were 20.7 and 5.1 cd/A, respectively. A 30% enhancement in the overall current efficiency was achieved by taking advantage of the MC effect and the low sheet resistance.

  9. Defective i6A37 Modification of Mitochondrial and Cytosolic tRNAs Results from Pathogenic Mutations in TRIT1 and Its Substrate tRNA

    PubMed Central

    Pyle, Angela; Mattijssen, Sandy; Baruffini, Enrico; Bruni, Francesco; Donnini, Claudia; Vassilev, Alex; He, Langping; Blakely, Emma L.; Griffin, Helen; Santibanez-Koref, Mauro; Bindoff, Laurence A.; Ferrero, Ileana; Chinnery, Patrick F.; McFarland, Robert; Maraia, Richard J.; Taylor, Robert W.

    2014-01-01

    Identifying the genetic basis for mitochondrial diseases is technically challenging given the size of the mitochondrial proteome and the heterogeneity of disease presentations. Using next-generation exome sequencing, we identified in a patient with severe combined mitochondrial respiratory chain defects and corresponding perturbation in mitochondrial protein synthesis, a homozygous p.Arg323Gln mutation in TRIT1. This gene encodes human tRNA isopentenyltransferase, which is responsible for i6A37 modification of the anticodon loops of a small subset of cytosolic and mitochondrial tRNAs. Deficiency of i6A37 was previously shown in yeast to decrease translational efficiency and fidelity in a codon-specific manner. Modelling of the p.Arg323Gln mutation on the co-crystal structure of the homologous yeast isopentenyltransferase bound to a substrate tRNA, indicates that it is one of a series of adjacent basic side chains that interact with the tRNA backbone of the anticodon stem, somewhat removed from the catalytic center. We show that patient cells bearing the p.Arg323Gln TRIT1 mutation are severely deficient in i6A37 in both cytosolic and mitochondrial tRNAs. Complete complementation of the i6A37 deficiency of both cytosolic and mitochondrial tRNAs was achieved by transduction of patient fibroblasts with wild-type TRIT1. Moreover, we show that a previously-reported pathogenic m.7480A>G mt-tRNASer(UCN) mutation in the anticodon loop sequence A36A37A38 recognised by TRIT1 causes a loss of i6A37 modification. These data demonstrate that deficiencies of i6A37 tRNA modification should be considered a potential mechanism of human disease caused by both nuclear gene and mitochondrial DNA mutations while providing insight into the structure and function of TRIT1 in the modification of cytosolic and mitochondrial tRNAs. PMID:24901367

  10. ITO-MgF2 Film Development for PowerSphere Polymer Surface Protection

    NASA Technical Reports Server (NTRS)

    Hambourger, Paul D.; Kerslake, Thomas W.; Waters, Deborah L.

    2004-01-01

    Multi-kilogram class microsatellites with a PowerSphere electric power system are attractive for fulfilling a variety of potential NASA missions. However, PowerSphere polymer surfaces must be coated with a film that has suitable electrical sheet resistivity for electrostatic discharge control, be resistant to atomic oxygen attack, be transparent to ultraviolet light for composite structure curing and resist ultraviolet light induced darkening for efficient photovoltaic cell operation. In addition, the film must be tolerant of polymer layer folding associated with launch stowage of PowerSphere inflatable structures. An excellent film material candidate to meet these requirements is co-sputtered, indium oxide (In2O3) - tin oxide (SnO2), known as 'ITO', and magnesium fluoride (MgF2). While basic ITO-MgF2 film properties have been the subject of research over the last decade, further research is required in the areas of film durability for space-inflatable applications and precise film property control for large scale commercial production. In this paper, the authors present film durability results for a folded polymer substrate and film resistance to vacuum UV darkening. The authors discuss methods and results in the area of film sheet resistivity measurement and active control, particularly dual-channel, plasma emission line measurement of ITO and MgF2 plasma sources. ITO-MgF2 film polymer coupon preparation is described as well as film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed microscopically and electrically. Results show that an approx. 500A ITO-18vol% MgF2 film is a promising candidate to protect PowerSphere polymer surfaces for Earth orbit missions. Preliminary data also indicate that in situ film measurement methods are promising for active film resistivity control in future large scale production. Future film research plans are also

  11. Bipolar resistive switching behaviors of ITO nanowire networks

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Gong, Zhina; Wang, Shuai; Wang, Jiangteng; Zhang, Ye; Yun, Feng

    2016-02-01

    We have fabricated indium tin oxide (ITO) nanowire (NW) networks on aluminum electrodes using electron beam evaporation. The Ag/ITO-NW networks/Al capacitor exhibits bipolar resistive switching behavior. The resistive switching characteristics of ITO-NW networks are related to the morphology of NWs. The x-ray photoelectron spectroscopy was used to obtain the chemical nature from the NWs surface, investigating the oxygen vacancy state. A stable switching voltages and a clear memory window were observed in needle-shaped NWs. The ITO-NW networks can be used as a new two-dimensional metal oxide material for the fabrication of high-density memory devices.

  12. Surface modification of amorphous substrates by disulfide derivatives: A photo-assisted route to direct functionalization of chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Amalric, Julien; Marchand-Brynaert, Jacqueline

    2011-12-01

    A novel route for chalcogenide glass surface modification is disclosed. The formation of an organic monolayer from disulfide derivatives is studied on two different glasses of formula GexAsySez by water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). The potential anchoring group is the disulfide functionality. Since thioctic acid derivatives absorb around 335 nm, an irradiation step is included, in order to favor S-S disruption. Three types of disulfide compounds are grafted onto small glass breaks for contact angle and XPS analyses. The results show effective changes of surface state. According to contact angle measurement, the deposited organic layer functionalized by a small polyethylene glycol chain leads to a more hydrophilic surface, long alkyl chain or a perfluorinated carbon chain leads to a more hydrophobic surface. XPS shows the presence at the surface of an organic layer with sulfur and ethylene oxide chains, or augmentation of organic carbons or fluorine and Csbnd F bonds. The photo-assisted grafting of the disulfides onto an ATR prism made of chalcogenide glass shows that this surface modification process does not affect infrared transparency, despite UV treatment, and accurate structural analysis can be performed.

  13. Ion implantation modified stainless steel as a substrate for hydroxyapatite deposition. Part I. Surface modification and characterization.

    PubMed

    Pramatarova, L; Pecheva, E; Krastev, V; Riesz, F

    2007-03-01

    Material surfaces play critical role in biology and medicine since most biological reactions occur on surfaces and interfaces. There are many examples showing that the surface properties of the materials control and are directly involved in biological reactions and processes in-vitro like blood compatibility, protein absorption, cell development, etc. The rules that govern the diversity of biological surface phenomenon are fundamental physical laws. Stainless steel doped with Cr, Ni and Mo is widely used material in medicine and dentistry due to its excellent corrosion resistance and mechanical properties. The interest in this material has stimulated extensive studies on improving its bone-bonding properties. This paper describes the surface modification of Cr-Ni stainless steel (AISI 316) by a whole surface sequential implantation of Ca and P ions (the basic ions of hydroxyapatite). Three groups of stainless steel samples are prepared: (i) ion-implanted, (ii) ion-implanted and thermally treated at 600( composite function)C in air for 1 h and (iii) initials. The surface chemistry and topography before and after the surface modification are characterized by X-ray photoelectron spectroscopy, Auger electron spectroscopy, magic mirror method, atomic force microscopy and contact angle measurements. PMID:17334693

  14. Studies on Ferromagnetic and Photoluminescence Properties of ITO and Cu-Doped ITO Nanoparticles Synthesized by Solid State Reaction

    NASA Astrophysics Data System (ADS)

    Babu, S. Harinath; Kaleemulla, S.; Rao, N. Madhusudhana; Krishnamoorthi, C.

    2016-07-01

    Cubic structured indium-tin-oxide (ITO) and copper-doped ITO nanoparticles were synthesized by solid state reaction. The structure, morphology, chemical, magnetic, and photoluminescence properties of the synthesized nanoparticles were studied by x-ray diffraction, field emission scanning electron microscopy, x-ray photoelectron spectroscopy, vibrating sample magnetometry, and photoluminescence spectrophotometry, respectively. Magnetic studies confirmed that the ITO nanoparticles were ferromagnetic at room temperature (300 K) and at 100 K, and it was believed that the observed ferromagnetism may be due to oxygen vacancies and defects present in the system. No hysteresis loop was observed in copper-doped ITO nanoparticles at room temperature and 100 K. The ITO and Cu-doped ITO nanoparticles exhibited two broad emission peaks in the visible region of the electromagnetic spectrum.

  15. A Sensitive Microplate Assay for Lipase Activity Measurement Using Olive Oil Emulsion Substrate: Modification of the Copper Soap Colorimetric Method.

    PubMed

    Mustafa, Ahmad; Karmali, Amin; Abdelmoez, Wael

    2016-01-01

    The present work involves a sensitive high-throughput microtiter plate based colorimetric assay for estimating lipase activity using cupric acetate pyridine reagent (CAPR). In the first approach, three factors two levels factorial design methodology was used to evaluate the interactive effect of different parameters on the sensitivity of the assay method. The optimization study revealed that the optimum CAPR concentration was 7.5% w/v, the optimum solvent was heptane and the optimum CAPR pH was 6. In the second approach, the optimized colorimetric microplate assay was used to measure lipase activity based on enzymatic hydrolysis of olive oil emulsion substrate at 37°C and 150 rpm. The emulsion substrates were formulated by using olive oil, triton X-100 (10% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 1:1:1 in the case of Candida sp. lipase. While in the case of immobilized lipozyme RMIM, The emulsion substrates were formulated by using olive oil, triton X-100 (1% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 2:1:1. Absorbance was measured at 655 nm. The stability of this assay (in terms of colored heptane phase absorbance readings) retained more than 92.5% after 24 h at 4°C compared to the absorbance readings measured at zero time. In comparison with other lipase assay methods, beside the developed sensitivity, the reproducibility and the lower limit of detection (LOD) of the proposed method, it permits analyzing of 96 samples at one time in a 96-well microplate. Furthermore, it consumes small quantities of chemicals and unit operations. PMID:27581492

  16. Electrical and Plasmonic Properties of Ligand-Free Sn(4+) -Doped In2 O3 (ITO) Nanocrystals.

    PubMed

    Jagadeeswararao, Metikoti; Pal, Somnath; Nag, Angshuman; Sarma, D D

    2016-03-01

    Sn(4+) -doped In2 O3 (ITO) is a benchmark transparent conducting oxide material. We prepared ligand-free but colloidal ITO (8 nm, 10 % Sn(4+) ) nanocrystals (NCs) by using a post-synthesis surface-modification reaction. (CH3 )3 OBF4 removes the native oleylamine ligand from NC surfaces to give ligand-free, positively charged NCs that form a colloidal dispersion in polar solvents. Both oleylamine-capped and ligand-free ITO NCs exhibit intense absorption peaks, due to localized surface plasmon resonance (LSPR) at around λ=1950 nm. Compared with oleylamine-capped NCs, the electrical resistivity of ligand-free ITO NCs is lower by an order of magnitude (≈35 mΩ cm(-1) ). Resistivity over a wide range of temperatures can be consistently described as a composite of metallic ITO grains embedded in an insulating matrix by using a simple equivalent circuit, which provides an insight into the conduction mechanism in these systems. PMID:26710967

  17. Degradation-by-design: Surface modification with functional substrates that enhance the enzymatic degradation of carbon nanotubes.

    PubMed

    Sureshbabu, Adukamparai Rajukrishnan; Kurapati, Rajendra; Russier, Julie; Ménard-Moyon, Cécilia; Bartolini, Isacco; Meneghetti, Moreno; Kostarelos, Kostas; Bianco, Alberto

    2015-12-01

    Biodegradation of carbon-based nanomaterials has been pursued intensively in the last few years, as one of the most crucial issues for the design of safe, clinically relevant conjugates for biomedical applications. In this paper it is demonstrated that specific functional molecules can enhance the catalytic activity of horseradish peroxidase (HRP) and xanthine oxidase (XO) for the degradation of carbon nanotubes. Two different azido coumarins and one cathecol derivative are linked to multi-walled carbon nanotubes (MWCNTs). These molecules are good reducing substrates and strong redox mediators to enhance the catalytic activity of HRP. XO, known to metabolize various molecules mainly in the mammalian liver, including human, was instead used to test the biodegradability of MWCNTs modified with an azido purine. The products of the biodegradation process are characterized by transmission electron microscopy and Raman spectroscopy. The results indicate that coumarin and catechol moieties have enhanced the biodegradation of MWCNTs compared to oxidized nanotubes, likely due to the capacity of these substrates to better interact with and activate HRP. Although azido purine-MWCNTs are degraded less effectively by XO than oxidized nanotubes, the data uncover the importance of XO in the biodegradation of carbon-nanomaterials leading to their better surface engineering for biomedical applications. PMID:26342557

  18. Large-area flexible monolithic ITO/WO3/Nb2O5/NiVOχ/ITO electrochromic devices prepared by using magnetron sputter deposition

    NASA Astrophysics Data System (ADS)

    Tang, Chien-Jen; Ye, Jia-Ming; Yang, Yueh-Ting; He, Ju-Liang

    2016-05-01

    Electrochromic devices (ECDs) have been applied in smart windows to control the transmission of sunlight in green buildings, saving up to 40-50% electricity consumption and ultimately reducing carbon dioxide emissions. However, the high manufacturing costs and difficulty of transportation of conventional massive large area ECDs has limited widespread applications. A unique design replacing the glass substrate commonly used in the ECD windows with inexpensive, light-weight and flexible polymeric substrate materials would accelerate EC adoption allowing them to be supplemented for regular windows without altering window construction. In this study, an ITO/WO3/Nb2O5/NiVOχ/ITO all-solid-state monolithic ECD with an effective area of 24 cm × 18 cm is successfully integrated on a PET substrate by using magnetron sputter deposition. The electrochromic performance and bending durability of the resultant material are also investigated. The experimental results indicate that the ultimate response times for the prepared ECD is 6 s for coloring at an applied voltage of -3 V and 5 s for bleaching at an applied voltage of +3 V, respectively. The optical transmittances for the bleached and colored state at a wavelength of 633 nm are 53% and 11%, respectively. The prepared ECD can sustain over 8000 repeated coloring and bleaching cycles, as well as tolerate a bending radius of curvature of 7.5 cm.

  19. Study of low resistivity and high work function ITO films prepared by oxygen flow rates and N2O plasma treatment for amorphous/crystalline silicon heterojunction solar cells.

    PubMed

    Hussain, Shahzada Qamar; Oh, Woong-Kyo; Kim, Sunbo; Ahn, Shihyun; Le, Anh Huy Tuan; Park, Hyeongsik; Lee, Youngseok; Dao, Vinh Ai; Velumani, S; Yi, Junsin

    2014-12-01

    Pulsed DC magnetron sputtered indium tin oxide (ITO) films deposited on glass substrates with lowest resistivity of 2.62 x 10(-4) Ω x cm and high transmittance of about 89% in the visible wavelength region. We report the enhancement of ITO work function (Φ(ITO)) by the variation of oxygen (O2) flow rate and N2O surface plasma treatment. The Φ(ITO) increased from 4.43 to 4.56 eV with the increase in O2 flow rate from 0 to 4 sccm while surface treatment of N2O plasma further enhanced the ITO work function to 4.65 eV. The crystallinity of the ITO films improved with increasing O2 flow rate, as revealed by XRD analysis. The ITO work function was increased by the interfacial dipole resulting from the surface rich in O- ions and by the dipole moment formed at the ITO surface during N2O plasma treatment. The ITO films with high work functions can be used to modify the front barrier height in heterojunction with intrinsic thin layer (HIT) solar cells. PMID:25971043

  20. Isothiourea-Mediated Organocatalytic Michael Addition-Lactonization on a Surface: Modification of SAMs on Silicon Oxide Substrates.

    PubMed

    Chisholm, Ross; Parkin, John D; Smith, Andrew D; Hähner, Georg

    2016-04-01

    Tailoring the functionality of self-assembled monolayers (SAMs) can be achieved either by depositing prefunctionalized molecules with the appropriate terminal groups or by chemical modification of an existing SAM in situ. The latter approach is particularly advantageous to allow for diversity of surface functionalization from a single SAM and if the incorporation of bulky groups is desired. In the present study an organocatalytic isothiourea-mediated Michael addition-lactonization process analogous to a previously reported study in solution is presented. An achiral isothiourea, 3,4-dihydro-2H-pyrimido[2,1-b]benzothiazole (DHPB), promotes the intermolecular Michael addition-lactonization of a trifluoromethylenone terminated SAM and a variety of arylacetic acids affording C(6)-trifluoromethyldihydropyranones tethered to the surface. X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, and ellipsometry analysis were conducted to confirm the presence of the substituted dihydropyranone. A model study of this approach was also performed in solution to probe the reaction diastereoselectivity as it cannot be measured directly on the surface. PMID:27015037

  1. Use of chemical modification and mass spectrometry to identify substrate-contacting sites in proteinaceous RNase P, a tRNA processing enzyme

    PubMed Central

    Chen, Tien-Hao; Tanimoto, Akiko; Shkriabai, Nikoloz; Kvaratskhelia, Mamuka; Wysocki, Vicki; Gopalan, Venkat

    2016-01-01

    Among all enzymes in nature, RNase P is unique in that it can use either an RNA- or a protein-based active site for its function: catalyzing cleavage of the 5′-leader from precursor tRNAs (pre-tRNAs). The well-studied catalytic RNase P RNA uses a specificity module to recognize the pre-tRNA and a catalytic module to perform cleavage. Similarly, the recently discovered proteinaceous RNase P (PRORP) possesses two domains – pentatricopeptide repeat (PPR) and metallonuclease (NYN) – that are present in some other RNA processing factors. Here, we combined chemical modification of lysines and multiple-reaction monitoring mass spectrometry to identify putative substrate-contacting residues in Arabidopsis thaliana PRORP1 (AtPRORP1), and subsequently validated these candidate sites by site-directed mutagenesis. Using biochemical studies to characterize the wild-type (WT) and mutant derivatives, we found that AtPRORP1 exploits specific lysines strategically positioned at the tips of it's V-shaped arms, in the first PPR motif and in the NYN domain proximal to the catalytic center, to bind and cleave pre-tRNA. Our results confirm that the protein- and RNA-based forms of RNase P have distinct modules for substrate recognition and cleavage, an unanticipated parallel in their mode of action. PMID:27166372

  2. Use of chemical modification and mass spectrometry to identify substrate-contacting sites in proteinaceous RNase P, a tRNA processing enzyme.

    PubMed

    Chen, Tien-Hao; Tanimoto, Akiko; Shkriabai, Nikoloz; Kvaratskhelia, Mamuka; Wysocki, Vicki; Gopalan, Venkat

    2016-06-20

    Among all enzymes in nature, RNase P is unique in that it can use either an RNA- or a protein-based active site for its function: catalyzing cleavage of the 5'-leader from precursor tRNAs (pre-tRNAs). The well-studied catalytic RNase P RNA uses a specificity module to recognize the pre-tRNA and a catalytic module to perform cleavage. Similarly, the recently discovered proteinaceous RNase P (PRORP) possesses two domains - pentatricopeptide repeat (PPR) and metallonuclease (NYN) - that are present in some other RNA processing factors. Here, we combined chemical modification of lysines and multiple-reaction monitoring mass spectrometry to identify putative substrate-contacting residues in Arabidopsis thaliana PRORP1 (AtPRORP1), and subsequently validated these candidate sites by site-directed mutagenesis. Using biochemical studies to characterize the wild-type (WT) and mutant derivatives, we found that AtPRORP1 exploits specific lysines strategically positioned at the tips of it's V-shaped arms, in the first PPR motif and in the NYN domain proximal to the catalytic center, to bind and cleave pre-tRNA. Our results confirm that the protein- and RNA-based forms of RNase P have distinct modules for substrate recognition and cleavage, an unanticipated parallel in their mode of action. PMID:27166372

  3. Unipolar resistive switching in a transparent ITO/SiOx/ITO sandwich fabricated at room temperature

    NASA Astrophysics Data System (ADS)

    Liu, Chih-Yi; Shih, Ya-Ru; Huang, Shyh-Jer

    2013-04-01

    A transparent indium tin oxide (ITO)/SiOx/ITO structure was fabricated at room temperature and its resistive switching behaviors were investigated. The average optical transmittance of the structure in the visible region was about 84%. The device demonstrated a unipolar resistive switching behavior. The X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometer results of the SiOx film indicated that many oxygen vacancies were within the SiOx film. From the switching behavior, the temperature coefficient of resistance, and the size effect of resistance, the resistive memory behavior can be explained based on conducting filaments composed of oxygen vacancies. The resistive switching behavior is then explained by the rupture and the formation of filaments near the top electrode.

  4. Highly flexible, hybrid-structured indium tin oxides for transparent electrodes on polymer substrates

    SciTech Connect

    Triambulo, Ross E.; Kim, Jung-Hoon; Park, Jin-Woo; Na, Min-Young; Chang, Hye-Jung

    2013-06-17

    We developed highly flexible, hybrid-structured crystalline indium tin oxide (ITO) for use as transparent electrodes on polymer substrates by embedding Ag nanoparticles (AgNPs) into the substrate. The hybrid ITO consists of domains in one orientation grown on the AgNPs and a matrix of the other orientation. The domains are stronger than the matrix and function as barriers to crack propagation. As a result, both the critical bending radius (r{sub c}) (under which the resistivity change ({Delta}{rho}) is less than a given value) and the change in {Delta}{rho} with decreasing r significantly decreased in the hybrid ITO compared with homogenous ITO.

  5. Fabrication and characterization of a CuO/ITO heterojunction with a graphene transparent electrode

    NASA Astrophysics Data System (ADS)

    Mageshwari, K.; Han, Sanghoo; Park, Jinsub

    2016-05-01

    In this paper, we investigate the electrical properties of a CuO-ITO heterojunction diode with the use of a graphene transparent electrode by current-voltage (I-V) characteristics. CuO thin films were deposited onto an ITO substrate by a simple sol-gel spin coating method and annealed at 500 °C. The x-ray diffraction pattern of the CuO thin films revealed the polycrystalline nature of CuO and exhibited a monoclinic crystal structure. FESEM images showed a uniform and densely packed particulate morphology. The optical band gap of CuO thin films estimated using UV-vis absorption spectra was found to be 2.50 eV. The I-V characteristics of the fabricated CuO-ITO heterojunction showed a well-defined rectifying behavior with improved electrical properties after the insertion of graphene. The electronic parameters of the heterostructure such as barrier height, ideality factor and series resistance were determined from the I-V measurements, and the possible current transport mechanism was discussed.

  6. Electronic Structure of C60/Phthalocyanine/ITO Interfaces Studied using Soft X-ray Spectroscopies

    SciTech Connect

    Cho, S.; Piper, L; DeMasi, A; Preston, A; Smith, K; Chauhan, K; Sullivan, P; Hatton, R; Jones, T

    2010-01-01

    The interface electronic structure of a bilayer heterojunction of C{sub 60} and three different phthalocyanines grown on indium tin oxide (ITO) has been studied using synchrotron radiation-excited photoelectron spectroscopy. The energy difference between the highest occupied molecular orbital level of the phthalocyanine (donor) layer and the lowest unoccupied molecular orbital level of the C{sub 60} (acceptor) layer (E{sub HOMO}{sup D} - E{sub LUMO}{sup A}) was determined. The E{sub HOMO}{sup D} - E{sub LUMO}{sup A} of a heterojunction with boron subphthalocyanine chloride (SubPc) was found to be much larger than those of copper phthalocyanine (CuPc) and chloro-aluminum phthalocyanine (ClAlPc). This observation is discussed in terms of the difference of the ionization energy of each donor material. Additionally, we have studied the molecular orientation of the phthalocyanine films on ITO using angle-dependent X-ray absorption spectroscopy. We found that the SubPc films showed significant disorder compared to the CuPc and ClAlPc films and also found that E{sub HOMO}{sup D} - E{sub LUMO}{sup A} varied with the orientation of the ClAlPc molecules relative to the ITO substrate. This orientation could be controlled by varying the ClAlPc deposition rate.

  7. Catalytic water oxidation on derivatized nanoITO

    SciTech Connect

    Chen, Zuofeng; Concepcion, Javier J; Hull, Jonathan Frazer; Hoertz, Paul G.; Meyer, Thomas J.

    2010-01-01

    Electrocatalytic water oxidation occurs on high surface area, nanocrystalline ITO (nanoITO) surface-derivatized by phosphonate-binding of the catalyst [Ru(Mebimpy)(4,4'-((HO)2OPCH2)2bpy)(OH2)]2+ (Mebimpy is 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; bpy is 2,2'-bipyridine). With nanoITO, spectral data can be acquired on electrochemically generated intermediates and voltammograms monitored spectrophotometrically.

  8. Fabrication of Flexible Au/ZnO/ITO/PET Memristor Using Dilute Electrodeposition Method

    NASA Astrophysics Data System (ADS)

    Fauzi, F. B.; Ani, M. H.; Othman, R.; Azhar, A. Z. A.; Mohamed, M. A.; Herman, S. H.

    2015-11-01

    DRAM has been approaching its maximum physical limit due to the demand of smaller size and higher capacity memory resistor. The researchers have discovered the abilities of a memristor, a Non Volatile Memory (NVM) that could overcome the size and capacity obstacles. This paper discussed about the deposition of zinc oxide (ZnO) on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrate by electrodeposition. Metallic Zn film was deposited on substrates with varying deposition time from 15 to 120 seconds in very dilute zinc chloride (ZnCl2) aqueous and subsequently oxidized at 150 °C to form ZnO/ITO coated PET junction. The deposited thin film was characterized via x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The results from I-V measurement show the deposited ZnO exhibits pinched hysteresis loop. The hysteresis loop becomes smaller with increasing deposition time. The 15 seconds electrodeposition gave the largest hysteresis loop and largest value of resistive switching ratio of 1.067. The result of the synthesized ZnO on the flexible substrate can be one of the alternatives to replace the current memory system as the flexible memory system.

  9. Multifractal analysis of time series generated by discrete Ito equations

    SciTech Connect

    Telesca, Luciano; Czechowski, Zbigniew; Lovallo, Michele

    2015-06-15

    In this study, we show that discrete Ito equations with short-tail Gaussian marginal distribution function generate multifractal time series. The multifractality is due to the nonlinear correlations, which are hidden in Markov processes and are generated by the interrelation between the drift and the multiplicative stochastic forces in the Ito equation. A link between the range of the generalized Hurst exponents and the mean of the squares of all averaged net forces is suggested.

  10. Direct laser patterning of transparent ITO-Ag-ITO multilayer anodes for organic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Joong; Seo, Ki-Won; Kim, Yong Hyeon; Choi, Jiyeon; Kim, Han-Ki

    2015-02-01

    Direct laser patterning of transparent ITO-Ag-ITO (IAI) multilayer anodes is investigated using a femtosecond fiber laser for application in organic solar cells (OSC) fabrication. By adjusting laser fluence and scan speed, we successfully patterned the IAI multilayer anode without changing the electrical or optical properties. At an optimized laser fluence of 0.6 J/cm2 and a scan speed of 200 mm/s, the patterned IAI multilayer was electrically isolated with a clean edge. The metallic Ag interlayer of the IAI multilayer plays an important role in direct laser patterning because it absorbed the laser and increases the maximum temperature in the IAI multilayer. In addition, the Ag layer could effectively decrease the temperature of the IAI multilayer after irradiation of laser. The OSC fabricated on the laser patterned IAI multilayer showed power conversion efficiencies of 3.12% (Ag 8 nm) and 2.85% (Ag 12 nm). Successful operation of the OSC indicates that direct laser patterning of IAI multilayer anodes is a promising, simple patterning technology for fabrication of IAI-based OSCs.

  11. Effect of Self-Assembled Monolayer Modification on Indium-Tin Oxide Surface for Surface-Initiated Vapor Deposition Polymerization of Carbazole Thin Films

    NASA Astrophysics Data System (ADS)

    Yuya Umemoto,; Seong-Ho Kim,; Rigoberto C. Advincula,; Kuniaki Tanaka,; Hiroaki Usui,

    2010-04-01

    With the aim of controlling the interface between an inorganic electrode and an organic layer, a surface-initiated vapor deposition polymerization method was employed to prepare carbazole polymer thin films that are chemically bound to an indium-tin oxide (ITO) surface. A self-assembled monolayer (SAM) that has an azo initiator as a terminal group was prepared on an ITO surface, on which carbazole acrylate monomers were evaporated under ultraviolet (UV) irradiation. The surface morphological characteristics of the films prepared with/without UV irradiation and with/without the SAM were compared. It was found that the UV irradiation leads to the polymerization of carbazole monomers irrespective of the type of substrate used. On the other hand, the surface morphological characteristics were largely dependent on the existence of the SAM. Uniform and smooth polymer thin films were obtained only when the monomers were evaporated on the SAM-modified surface under UV irradiation. A comparison of film growth characteristics on a UV-ozone-treated ITO surface suggested that the formation of uniform films was made possible not by the modification of surface energy but by the growth of the polymers chemically bound to the substrate surface.

  12. Metal-free molecular junctions on ITO via amino-silane binding—towards optoelectronic molecular junctions

    NASA Astrophysics Data System (ADS)

    Sergani, S.; Furmansky, Y.; Visoly-Fisher, I.

    2013-11-01

    Light control over currents in molecular junctions is desirable as a non-contact input with high spectral and spatial resolution provided by the photonic input and the molecular electronics element, respectively. Expanding the study of molecular junctions to non-metallic transparent substrates, such as indium tin oxide (ITO), is vital for the observation of molecular optoelectronic effects. Non-metallic electrodes are expected to decrease the probability of quenching of molecular photo-excited states, light-induced plasmonic effects, or significant electrode expansion under visible light. We have developed micron-sized, metal free, optically addressable ITO molecular junctions with a conductive polymer serving as the counter-electrode. The electrical transport was shown to be dominated by the nature of the self-assembled monolayer (SAM). The use of amino-silane (APTMS) as the chemical binding scheme to ITO was found to be significant in determining the transport properties of the junctions. APTMS allows high junction yields and the formation of dense molecular layers preventing electrical short. However, polar amino-silane binding to the ITO significantly decreased the conductance compared to thiol-bound SAMs, and caused tilted geometry and disorder in the molecular layer. As the effect of the molecular structure on transport properties is clearly observed in our junctions, such metal-free junctions are suitable for characterizing the optoelectronic properties of molecular junctions.

  13. Metal-free molecular junctions on ITO via amino-silane binding-towards optoelectronic molecular junctions.

    PubMed

    Sergani, S; Furmansky, Y; Visoly-Fisher, I

    2013-11-15

    Light control over currents in molecular junctions is desirable as a non-contact input with high spectral and spatial resolution provided by the photonic input and the molecular electronics element, respectively. Expanding the study of molecular junctions to non-metallic transparent substrates, such as indium tin oxide (ITO), is vital for the observation of molecular optoelectronic effects. Non-metallic electrodes are expected to decrease the probability of quenching of molecular photo-excited states, light-induced plasmonic effects, or significant electrode expansion under visible light. We have developed micron-sized, metal free, optically addressable ITO molecular junctions with a conductive polymer serving as the counter-electrode. The electrical transport was shown to be dominated by the nature of the self-assembled monolayer (SAM). The use of amino-silane (APTMS) as the chemical binding scheme to ITO was found to be significant in determining the transport properties of the junctions. APTMS allows high junction yields and the formation of dense molecular layers preventing electrical short. However, polar amino-silane binding to the ITO significantly decreased the conductance compared to thiol-bound SAMs, and caused tilted geometry and disorder in the molecular layer. As the effect of the molecular structure on transport properties is clearly observed in our junctions, such metal-free junctions are suitable for characterizing the optoelectronic properties of molecular junctions. PMID:24129428

  14. Catalyst-free growth of ZnO nanowires on ITO seed layer/glass by thermal evaporation method: Effects of ITO seed layer laser annealing temperature

    NASA Astrophysics Data System (ADS)

    Alsultany, Forat H.; Hassan, Z.; Ahmed, Naser M.

    2016-04-01

    Novel catalyst-free growth of ZnO nanowires (ZnO-NWs) on ITO seeds/glass substrate by thermal evaporation method, and effects of continuous wave CO2 laser thermal annealed seed layer on the morphology and properties of ZnO-NWs growth were investigated. The effects of sputtered ITO seed layer laser annealing temperature on the morphological, structural, and optical properties of ZnO-NWs was systematically investigated at temperatures 250, 350, and 450 °C, respectively. The surface morphology and structure of the seeds and the products of ZnO-NWs were characterized in detail by using field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Optical properties were further examined through photoluminescence, and UV-Vis spectrophotometer. A growth mechanism was proposed on the basis of obtained results. The results showed that the nanowires were strongly dependent on the seed layer annealing temperatures, which played an important role in nucleation and dissimilar growth of the nanowires with varying sizes and geometric shapes.

  15. Ubiquitin modifications

    PubMed Central

    Swatek, Kirby N; Komander, David

    2016-01-01

    Protein ubiquitination is a dynamic multifaceted post-translational modification involved in nearly all aspects of eukaryotic biology. Once attached to a substrate, the 76-amino acid protein ubiquitin is subjected to further modifications, creating a multitude of distinct signals with distinct cellular outcomes, referred to as the 'ubiquitin code'. Ubiquitin can be ubiquitinated on seven lysine (Lys) residues or on the N-terminus, leading to polyubiquitin chains that can encompass complex topologies. Alternatively or in addition, ubiquitin Lys residues can be modified by ubiquitin-like molecules (such as SUMO or NEDD8). Finally, ubiquitin can also be acetylated on Lys, or phosphorylated on Ser, Thr or Tyr residues, and each modification has the potential to dramatically alter the signaling outcome. While the number of distinctly modified ubiquitin species in cells is mind-boggling, much progress has been made to characterize the roles of distinct ubiquitin modifications, and many enzymes and receptors have been identified that create, recognize or remove these ubiquitin modifications. We here provide an overview of the various ubiquitin modifications present in cells, and highlight recent progress on ubiquitin chain biology. We then discuss the recent findings in the field of ubiquitin acetylation and phosphorylation, with a focus on Ser65-phosphorylation and its role in mitophagy and Parkin activation. PMID:27012465

  16. Polycrystalline ZnS(x)Se(1 - x) thin films deposited on ITO glass by MBE.

    PubMed

    Shen, Da-Ke; Sou, I K; Han, Gao-Rong; Du, Pi-Yi; Que, Duan-Lin

    2003-01-01

    MBE growth of ZnS(x)Se(1 - x) thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging from 270 degrees C to 330 degrees C . The XRD theta/2theta spectra resulted from these films indicated that the as-grown polycrystalline ZnS(x)Se(1 - x) thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 degrees C. Both AFM and TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnS(x)Se(1 - x) thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional micrograph showing a well defined columnar structure. PMID:12659224

  17. Fabrication of printed ITO sensor for the ammonia hydroxide detection

    NASA Astrophysics Data System (ADS)

    Lee, Seok-hwan; Koo, Jieun; Jung, Soohoon; Lee, Moonjin; Jung, Jung-Yeul; Chang, Jiho

    2015-07-01

    Monitoring the hazardous and noxious substances (HNS) is a very important issue for mitigating the influence of catastrophic accidents in ocean and coastal areas. However, research on the HNS sensor is just in the beginning stage. In this study, we proposed a new HNS sensor using a printed ITO layer. We carried out a series of experiments of detecting the NH4OH and seawater solution to investigate the feasibility as a HNS sensor. The resistance of ITO layer dropped abruptly when it soaked into the solutions. The resistance change (δR) was linearly correlated with the NH4OH concentration of the solution, also it can be classified into two states; one is the transition stage, the other is the stabilized stage. The former is considered to be caused by the large capacitance of the electrical double layer (EDL) on the ITO surface. Also, the ITO layer showed considerable chemical stability within our experimental condition. In this paper, we have investigated the feasibility of printed ITO layer as a sensitive and cheap HNS sensor.

  18. Solution-processed indium-tin-oxide nanoparticle transparent conductors on flexible glass substrate with high optical transmittance and high thermal stability

    NASA Astrophysics Data System (ADS)

    Hong, Sung-Jei; Kim, Sun-Woo; In Han, Jeong

    2014-08-01

    In this study, solution-processed transparent conductors on flexible glass substrate were investigated using indium-tin-oxide (ITO) nanoparticle (NP) ink. The ITO-NP conductors were well fabricated on the flexible glass substrate with neither distortion nor deformation. Optical transmittances of the ITO-NP conductors on flexible glass substrate were enhanced to more than 91% that is higher than those on rigid glass substrate owing to decreased thickness. As well, the ITO-NP conductors on flexible glass substrate heat-treated at 500 and 600 °C showed good thermal stabilities of electrical and optical properties. In case of bending characteristics of samples heat-treated at 500 and 600 °C, the change in resistance was slight within 14%, which is smaller than those of conventional TCOs on flexible films. Based on the results, we propose that the solution-processed ITO-NP conductors are suitable for TCOs on flexible glass substrates.

  19. Cleaning of ITO glass with carbon dioxide snow jet spray

    NASA Astrophysics Data System (ADS)

    Li, Jun-jian; Qi, Tong; Li, Shu-lin; Zhao, Guang

    2007-12-01

    ITO glass cleaning is LCD, OLED and other flat panel display industry's key technologies. At present, the usual wet cleaning technology consumes large amount of water and chemicals, and produces a large amount of contaminant venting. CO II snow jet spray cleaning has been successfully applied to cleaning the surface of semiconductor chip, vacuum devices and space telescopes. Surface cleaning of indium tin oxide (ITO) film was carried out with carbon dioxide snow jet treatment .Based on the measurements of the contact angles, X-ray photoelectron spectroscopy and scanning electron microscopy (SEM) ,the influence of carbon dioxide snow jet treatment on surface cleaning of indium tin Oxide film was investigated and compared with the samples of low frequency immersion ultrasonic cleaning. Experimental data show that the carbon dioxide snow jet treatment effectively removes particulate and hydrocarbon on ITO surface.

  20. Patterning ITO by Template-Assisted Colloidal-Lithography for Enhancing Power Conversion Efficiency in Organic Photovoltaic.

    PubMed

    Lee, Jin-Su; Yu, Jung-Hun; Hwang, Ki-Hwan; Nam, Sang-Hun; Boo, Jin-Hyo; Yun, Sang H

    2016-05-01

    Highly structured interfaces are very desirable in organic photovoltaic solar cells (OPVs), in order to enhance power conversion efficiency (PCE) by decreasing of the transport path for excited charge carriers in the absorber and increasing the optical path length for photon absorption. Many complicated, high-cost lithographic methods have been attempted to modify the surface of the absorber or substrate. However, solution-based colloidal-lithography processes are scalable and cost-effective, but generally result in non-uniform structured surfaces. In this report, we demonstrated an optimized silica-templated colloidal lithographical approach to create a well-defined and controlled transparent ITO layer for enhancing power conversion efficiency (PCE). Additionally, morphological effects of the patterned ITO on optical properties and PCE were analyzed in detail. PMID:27483864

  1. Carbon nanotube/Prussian blue thin films as cathodes for flexible, transparent and ITO-free potassium secondary battery.

    PubMed

    Nossol, Edson; Souza, Victor H R; Zarbin, Aldo J G

    2016-09-15

    Thin films of either unpurified single-walled carbon nanotubes (SWCNT) or iron-filled multi-walled carbon nanotubes (MWCNT) were deposited through the liquid-liquid interfacial route over plastic substrates, yielding transparent, flexible and ITO-free electrodes. The iron species presented in both electrodes (inside of the MWCNT cavities or outside of the SWCNT bundles, related to the catalyst remaining of the growth process) were employed as reactant to the electrosynthesis of Prussian blue (PB), yielding carbon nanotubes/Prussian blue nanocomposite thin films, which were characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy, cyclic voltammetry and galvanostatic charge/discharge measurements. The nanocomposite films were employed as cathodes for flexible, transparent and ITO-free potassium batteries, showing reversible charge/discharge behavior and specific capacitance of 8.3mAhcm(-3) and 2.7mAhcm(-3) for SWCNT/PB and MWCNT/PB, respectively. PMID:27288576

  2. The electric transport properties of Al-doped ZnO/BiFeO3/ITO glass heterostructure

    NASA Astrophysics Data System (ADS)

    Fan, Fei; Chen, Changle; Luo, Bingcheng; Jin, Kexin

    2011-04-01

    BiFeO3 (BFO) and 4 wt. % Al-doped ZnO (ZAO) layers were grown on indium tin oxide (ITO) glass substrate using a pulsed laser deposition (PLD) method. I-V curves of the ZAO/BFO/ITO glass structure were investigated over the temperature range from 60 to 240 K. Analysis of the leakage current demonstrates that Poole-Frenkel emission is the dominant mechanism in our sample. The relations between resistance and temperature at positive and negative bias voltages are different, and the difference arises from the ferroelectric switching in BFO and the interfacial depletion layer between the semiconducting and the ferroelectric layers. Magnetoresistance (MR) effect is observed and the negative MR is related to the electron spin-dependent scattering and the interface resistance of the heterostructure.

  3. Ito cells and fibrogenesis in chronic alcoholic liver disease.

    PubMed

    González-Reimers, C E; Brajín-Rodríguez, M M; Santolaria-Fernández, F; Diaz-Flores, L; Conde-Martel, A; Rodríguez-Rodríguez, E; Essardas-Daryanani, H

    1992-02-01

    The relationships between the number of Ito cells; serum N-terminal type III procollagen and laminin; clinical and biochemical parameters of liver function derangement; histomorphometrically assessed total amount of liver fibrosis; and daily ethanol intake were studied in 43 patients affected by chronic alcoholic liver disease (10 cirrhotics). Significant correlations were found between serum laminin and N-terminal type III procollagen and histological, clinical and biochemical data of liver function derangement, but no correlation was found between the aforementioned parameters and the percentage of Ito cells, which in turn seemed to be related to ethanol ingestion. PMID:1559427

  4. [60]-fullerene and single-walled carbon nanotube-based ultrathin films stepwise grafted onto a self-assembled monolayer on ITO.

    PubMed

    Wang, Qiguan; Moriyama, Hiroshi

    2009-09-15

    A step-by-step method was used to prepare homogeneous ultrathin films composed of [60]-fullerene (C60) and single-walled carbon nanotubes (SWNTs), grafted onto the functional surface of an alkylsilane self-assembled monolayer (SAM) on an ITO substrate with an ITO-C60-SWNT sequence using amine addition across a double bond in C60 followed by amidation coupling with acid-functionalized SWNTs. Atomic force microscope and scanning electron microscope images of the resulting composite film showed two-component ball-tube microstructures with high-density coverage, where C60 was homogeneously distributed in the SWNT forest. The attachment of SWNTs to the residual amine units in the SAM on the ITO substrate (SAM-ITO) as well as on the C60 sphere results in the C60 molecules in the aggregated clusters being more separately dispersed, which forms a densely packed composite film as a result of the pi-pi interaction between the C60 buckyballs and the SWNT walls. It was found using ferrocene as an internal redox probe that the oxidative and reductive processes at the film-solution surface were effectively retarded because of obstruction from the densely packed film and the electronic effect of SWNT and C60. In addition, the electrochemical properties of C60 on SAM-ITO plates observed by cyclic voltammetry were significantly modified by chemical anchorage using SWNTs. X-ray photoelectron spectroscopy (XPS) analysis also indicated the successful grafting of C60 and SWNT. The XPS chemical shift of the binding energy showed the presence of electronic interactions between C60, SWNT, and ITO components. Such a uniformly distributed C60-SWNT film may be useful for future research in electrochemical and photoactive nanodevices. PMID:19639982

  5. Molecular Determinants of Cardiac Transient Outward Potassium Current (Ito) Expression and Regulation

    PubMed Central

    Niwa, Noriko; Nerbonne, Jeanne M.

    2009-01-01

    Rapidly activating and inactivating cardiac transient outward K+ currents, Ito, are expressed in most mammalian cardiomyocytes, and contribute importantly to the early phase of action potential repolarization and to plateau potentials. The rapidly recovering (Ito,f) and slowly recovering (Ito,s) components are differentially expressed in the myocardium, contributing to regional heterogeneities in action potential waveforms. Consistent with the marked differences in biophysical properties, distinct pore-forming (α) subunits underlie the two Ito components: Kv4.3/Kv4.2 subunits encode Ito,f, whereas Kv1.4 encodes Ito,s, channels. It has also become increasingly clear that cardiac Ito channels function as components of macromolecular protein complexes, comprising (four) Kv α subunits and a variety of accessory subunits and regulatory proteins that influence channel expression, biophysical properties and interactions with the actin cytoskeleton, and contribute to the generation of normal cardiac rhythms. Derangements in the expression or the regulation of Ito channels in inherited or acquired cardiac diseases would be expected to increase the risk of potentially life-threatening cardiac arrhythmias. Indeed, a recently identified Brugada syndrome mutation in KCNE3 (MiRP2) has been suggested to result in increased Ito,f densities. Continued focus in this area seems certain to provide new and fundamentally important insights into the molecular determinants of functional Ito channels and into the molecular mechanisms involved in the dynamic regulation of Ito channel functioning in the normal and diseased myocardium. PMID:19619557

  6. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR... ITO which desires to participate in the Food Distribution Program shall file an application with...

  7. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR... ITO which desires to participate in the Food Distribution Program shall file an application with...

  8. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR... ITO which desires to participate in the Food Distribution Program shall file an application with...

  9. NonMarkov Ito Processes with 1- state memory

    NASA Astrophysics Data System (ADS)

    McCauley, Joseph L.

    2010-08-01

    A Markov process, by definition, cannot depend on any previous state other than the last observed state. An Ito process implies the Fokker-Planck and Kolmogorov backward time partial differential eqns. for transition densities, which in turn imply the Chapman-Kolmogorov eqn., but without requiring the Markov condition. We present a class of Ito process superficially resembling Markov processes, but with 1-state memory. In finance, such processes would obey the efficient market hypothesis up through the level of pair correlations. These stochastic processes have been mislabeled in recent literature as 'nonlinear Markov processes'. Inspired by Doob and Feller, who pointed out that the ChapmanKolmogorov eqn. is not restricted to Markov processes, we exhibit a Gaussian Ito transition density with 1-state memory in the drift coefficient that satisfies both of Kolmogorov's partial differential eqns. and also the Chapman-Kolmogorov eqn. In addition, we show that three of the examples from McKean's seminal 1966 paper are also nonMarkov Ito processes. Last, we show that the transition density of the generalized Black-Scholes type partial differential eqn. describes a martingale, and satisfies the ChapmanKolmogorov eqn. This leads to the shortest-known proof that the Green function of the Black-Scholes eqn. with variable diffusion coefficient provides the so-called martingale measure of option pricing.

  10. H/ACA small nucleolar RNA pseudouridylation pockets bind substrate RNA to form three-way junctions that position the target U for modification

    PubMed Central

    Wu, Haihong; Feigon, Juli

    2007-01-01

    During the biogenesis of eukaryotic ribosomal RNA (rRNA) and spliceosomal small nuclear RNA (snRNA), uridines at specific sites are converted to pseudouridines by H/ACA ribonucleoprotein particles (RNPs). Each H/ACA RNP contains a substrate-specific H/ACA RNA and four common proteins, the pseudouridine synthase Cbf5, Nop10, Gar1, and Nhp2. The H/ACA RNA contains at least one pseudouridylation (ψ) pocket, which is complementary to the sequences flanking the target uridine. In this article, we show structural evidence that the ψ pocket can form the predicted base pairs with substrate RNA in the absence of protein components. We report the solution structure of the complex between an RNA hairpin derived from the 3′ ψ pocket of human U65 H/ACA small nucleolar RNA (snoRNA) and the substrate rRNA. The snoRNA–rRNA substrate complex has a unique structure with two offset parallel pairs of stacked helices and two unusual intermolecular three-way junctions, which together organize the substrate for docking into the active site of Cbf5. The substrate RNA interacts on one face of the snoRNA in the complex, forming a structure that easily could be accommodated in the H/ACA RNP, and explains how successive substrate RNAs could be loaded onto and unloaded from the H/ACA RNA in the RNP. PMID:17412831

  11. Nd:YVO4 laser direct ablation of indium tin oxide films deposited on glass and polyethylene terephthalate substrates.

    PubMed

    Wang, Jian-Xun; Kwon, Sang Jik; Han, Jae-Hee; Cho, Eou Sik

    2013-09-01

    A Q-switched diode-pumped neodymium-doped yttrium vanadate (Nd:YVO4, lambda = 1064 nm) laser was applied to obtain the indium tin oxide (ITO) patterns on flexible polyethylene terephthalate (PET) substrate by a direct etching method. After the ITO films were deposited on a soda-lime glass and PET substrate, laser ablations were carried out on the ITO films for various conditions and the laser ablated results on the ITO films were investigated and analyzed considering the effects of substrates on the laser etching. The laser ablated widths on ITO deposited on glass were found to be much narrower than those on ITO deposited on PET substrate, especially, at a higher scanning speed of laser beam such as 1000 mm/s and 2000 mm/s. As the thermal conductivity of glass substrate is about 7.5 times higher than that of PET, more thermal energy would be spread and transferred to lateral direction in the ITO film in case of PET substrate. PMID:24205645

  12. SHI Induced Modifications in CdS/CuInSe{sub 2} Thin Film: XRD Analysis

    SciTech Connect

    Joshi, Rajesh A.; Taur, Vidya S.; Sharma, Ramphal; Ghule, Anil V.

    2011-07-15

    CuInSe{sub 2}(CIS nanostructured) thin films were prepared by ion exchange method at room temperature on ITO coated glass substrates in an alkaline medium. The as prepared thin films were irradiated by 120 MeV Au{sup 9+} swift heavy ion (SHI) at 5x10{sup 11} and 5x10{sup 12} ions/cm{sup 2} fluence respectively. To study the effect of irradiation, the pristine and irradiated nanostructured thin films were characterized by X ray Diffraction (XRD) and analyzed the improvement in crystalline quality and crystallite size. The observed structural modifications discussed considering the high electronic energy deposition by 120 MeV gold heavy (Au{sup 9+}) ions in CuInSe{sub 2} thin films.

  13. In situ electro-mechanical experiments and mechanics modeling of tensile cracking in indium tin oxide thin films on polyimide substrates

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Jia, Zheng; Bianculli, Dan; Li, Teng; Lou, Jun

    2011-05-01

    Indium tin oxide (ITO) thin films supported by polymer substrates have been widely used as transparent electrodes/interconnects in flexible electronics. Understanding the electro-mechanical behaviors of such material system is crucial for reliable operation of flexible devices under large deformation. In this paper, we performed in situ mechanical and electrical tests of ITO thin films with two different thicknesses (200 and 80 nm) deposited on polyimide substrates inside a scanning electron microscope. The crack initiation and propagation, crack density evolution and the corresponding electrical resistance variation were systematically investigated. It was found that cracks initiated at a higher tensile strain level and saturated with a higher density in thinner ITO films. Integrated with a coherently formulated mechanics model, the cohesive toughness and fracture strength of ITO thin films and the ITO/polyimide interfacial toughness were quantitatively determined. The experimentally observed thickness dependence of the saturated crack density in ITO thin films was also quantitatively verified by the model.

  14. Bispectrality of the Complementary Bannai-Ito Polynomials

    NASA Astrophysics Data System (ADS)

    Genest, Vincent X.; Vinet, Luc; Zhedanov, Alexei

    2013-03-01

    A one-parameter family of operators that have the complementary Bannai-Ito (CBI) polynomials as eigenfunctions is obtained. The CBI polynomials are the kernel partners of the Bannai-Ito polynomials and also correspond to a q→"1 limit of the Askey-Wilson polynomials. The eigenvalue equations for the CBI polynomials are found to involve second order Dunkl shift operators with reflections and exhibit quadratic spectra. The algebra associated to the CBI polynomials is given and seen to be a deformation of the Askey-Wilson algebra with an involution. The relation between the CBI polynomials and the recently discovered dual "1 Hahn and para-Krawtchouk polynomials, as well as their relation with the symmetric Hahn polynomials, is also discussed.

  15. Dielectric breakdown in mineral oil ITO 100 based magnetic fluid

    NASA Astrophysics Data System (ADS)

    Kudelcik, J.; Bury, P.; Kopcansky, P.; Timko, M.

    The development of dielectric breakdown and the DC dielectric breakdown voltage of magnetic fluids based on inhibited transformer oil ITO 100 were investigated in parallel orientations of external magnetic field. It was shown that the breakdown voltage is strongly influenced by the magnetic nanoparticles. The magnetic fluids with the volume concentration 1and 0.2% had better dielectric properties than pure transformer oil. The increase of breakdown voltage was interpreted on the base of the bubble theory of breakdown.

  16. Controlled synthesis of tin-doped indium oxide (ITO) nanowires

    NASA Astrophysics Data System (ADS)

    Li, Luping; Chen, Shikai; Kim, Jung; Xu, Cheng; Zhao, Yang; Ziegler, Kirk J.

    2015-03-01

    Because of their high optical transparency and high electrical conductivity, ITO nanowires have been used in solar cells, diodes, and sensors. Synthesizing ITO nanowires reliably with controllable and reproducible structures and morphologies is desirable for many applications. However, the dependence of ITO nanowire structure and morphology on growth conditions has yet to be investigated systematically. In this work, experimental conditions including catalyst diameter, growth time, temperature, and oxygen partial pressure are varied to determine their impact on the diameter, length, and microstructure of synthesized nanowires. The diameters of the nanowires depend on the diameter of Au catalysts, however, not as directly as other studies have observed. Nanowire diameters of 99 nm were obtained when using 14 nm Au nanoclusters compared to 366 nm when using 321 nm Au nanoclusters. Nanowire length and diameters are independent of O2 partial pressure. However, the O2 partial pressure had to remain below 3.23 mTorr for successful nanowire growth. The optimal temperature for nanowire growth was 750 °C.

  17. Properties of photoelectricity of WOx-doped ITO thin films

    NASA Astrophysics Data System (ADS)

    Liu, Ye; Li, Zhuying; Wang, Chong; Liu, Hui; Luo, Shan

    2010-10-01

    Indium-tin-oxide (ITO) film is an n-semiconductor transparent conductive film. It has many good properties: conductivity, transmittance in visible region, absorptivity in ultraviolet. And tungsten oxide has good conductivity and it can keep stable structure in high temperature, also it has wearable and anti-corrupt properties. Therefore, tungsten oxide can be added gradually on ITO thin films by magnetron sputtering to research the optical and electrical performance of the doped films. We research the performance of the doped films in five aspects: X-ray diffraction spectroscopy, Scanning electron microscope are used to investigate the crystal structure, surface morphology. UV-visible spectroscopy is used to display the transmittance and absorption spectrum of the films. The thin films' performance of electrochemistry is tested by the workstation of electrochemistry. Its conductivity is tested by Four-probe sheet resistivity meter. The main conclusion: The analysis of SEM results shows that the surface morphology of the films is granulated. Transmittance spectrums suggest that the transmittance of ITO films have been increased by proper doping, the percentage of transmittance is over 90% from visible to near-infrared region. Besides, it shows well in the properties of electricity and electrochemistry in the doped films.

  18. Dye-sensitized solar cell using sprayed ZnO nanocrystalline thin films on ITO as photoanode.

    PubMed

    Dhamodharan, P; Manoharan, C; Dhanapandian, S; Venkatachalam, P

    2015-02-01

    ZnO thin films had been successfully prepared by spray pyrolysis (SP) technique on ITO/Glass substrates at different substrate temperature in the range 250-400°C using Zinc acetylacetonate as precursor. The X-ray diffraction studies confirmed the hexagonal wurtzite structure with preferred orientation along (002) plane at substrate temperature 350°C and the crystallite size was found to vary from 18 to 47nm. The morphology of the films revealed the porous nature with the roughness value of 8-13nm. The transmittance value was found to vary from 60% to 85% in the visible region depending upon the substrate temperature and the band gap value for the film deposited at 350°C was 3.2eV. The obtained results revealed that the structures and properties of the films were greatly affected by substrate temperature. The near band edge emission observed at 398nm in PL spectra showed better crystallinity. The measured electrical resistivity for ZnO film was ∼3.5×10(-4)Ωcm at the optimized temperature 350°C and was of n-type semiconductor. The obtained porous nature with increased surface roughness of the film and good light absorbing nature of the dye paved way for implementation of quality ZnO in DSSCs fabrication. DSSC were assembled using the prepared ZnO film on ITO coated glass substrate as photoanode and its photocurrent - voltage performance was investigated. PMID:25459731

  19. Dye-sensitized solar cell using sprayed ZnO nanocrystalline thin films on ITO as photoanode

    NASA Astrophysics Data System (ADS)

    Dhamodharan, P.; Manoharan, C.; Dhanapandian, S.; Venkatachalam, P.

    2015-02-01

    ZnO thin films had been successfully prepared by spray pyrolysis (SP) technique on ITO/Glass substrates at different substrate temperature in the range 250-400 °C using Zinc acetylacetonate as precursor. The X-ray diffraction studies confirmed the hexagonal wurtzite structure with preferred orientation along (0 0 2) plane at substrate temperature 350 °C and the crystallite size was found to vary from 18 to 47 nm. The morphology of the films revealed the porous nature with the roughness value of 8-13 nm. The transmittance value was found to vary from 60% to 85% in the visible region depending upon the substrate temperature and the band gap value for the film deposited at 350 °C was 3.2 eV. The obtained results revealed that the structures and properties of the films were greatly affected by substrate temperature. The near band edge emission observed at 398 nm in PL spectra showed better crystallinity. The measured electrical resistivity for ZnO film was ∼3.5 × 10-4 Ω cm at the optimized temperature 350 °C and was of n-type semiconductor. The obtained porous nature with increased surface roughness of the film and good light absorbing nature of the dye paved way for implementation of quality ZnO in DSSCs fabrication. DSSC were assembled using the prepared ZnO film on ITO coated glass substrate as photoanode and its photocurrent - voltage performance was investigated.

  20. A three-dimensional metal grid mesh as a practical alternative to ITO.

    PubMed

    Jang, Sungwoo; Jung, Woo-Bin; Kim, Choelgyu; Won, Phillip; Lee, Sang-Gil; Cho, Kyeong Min; Jin, Ming Liang; An, Cheng Jin; Jeon, Hwan-Jin; Ko, Seung Hwan; Kim, Taek-Soo; Jung, Hee-Tae

    2016-08-01

    The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (∼350 nm) and thin (∼30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential requirements of transparent electrodes for practical applications in future opto-electronics: excellent optoelectronic performance (a sheet resistance of 9.8 Ω□(-1) with a transmittance of 85.2%), high stretchability (no significant change in resistance for applied strains <15%), a sub-micrometer mesh period, a flat surface (a root mean square roughness of approximately 5 nm), no haze (approximately 0.5%), and strong adhesion to polymer substrates (it survives attempted detachment with 3M Scotch tape). Such outstanding properties are attributed to the unique substrate-embedded 3D structure of the electrode, which can be obtained with a high aspect ratio and in high resolution over large areas with a simple process. As a demonstration of its suitability for practical applications, our transparent electrode was successfully tested in a flexible touch screen panel. We believe that our approach opens up new practical applications in wearable electronics. PMID:27404907

  1. Sputtering and surface structure modification of gold thin films deposited onto silicon substrates under the impact of 20-160 keV Ar+ ions

    NASA Astrophysics Data System (ADS)

    Mammeri, S.; Ouichaoui, S.; Ammi, H.; Dib, A.

    2014-10-01

    The induced sputtering and surface state modification of Au thin films bombarded by swift Ar+ ions under normal incident angle have been studied over an energy range of (20-160) keV using three complementary techniques: Rutherford backscattering spectroscopy (RBS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The sputtering yields determined by RBS measurements using a 2 MeV 4He+ ion beam were found to be consistent with previous data measured within the Ar+ ion energy region E ⩽ 50 keV, which are thus extended to higher bombarding energies. Besides, the SEM and XRD measurements clearly point out that the irradiated Au film surfaces undergo drastic modifications with increasing the Ar+ ion energy, giving rise to the formation of increasingly sized grains of preferred (1 1 1) crystalline orientations. The relevance of different sputtering yield models for describing experimental data is discussed with invoking the observed surface effects induced by the Ar+ ion irradiation.

  2. MOCVD Growth of High-Quality and Density-Tunable GaAs Nanowires on ITO Catalyzed by Au Nanoparticles Deposited by Centrifugation.

    PubMed

    Wu, Dan; Tang, Xiaohong; Yoon, Ho Sup; Wang, Kai; Olivier, Aurelien; Li, Xianqiang

    2015-12-01

    High-quality and density-tunable GaAs nanowires (NWs) are directly grown on indium tin oxide (ITO) using Au nanoparticles (NPs) as catalysts by metal organic chemical vapor deposition (MOCVD). Au catalysts were deposited on ITO glass substrate using a centrifugal method. Compared with the droplet-only method, high-area density Au NPs were uniformly distributed on ITO. Tunable area density was realized through variation of the centrifugation time, and the highest area densities were obtained as high as 490 and 120 NP/μm(2) for 10- and 20-nm diameters of Au NPs, respectively. Based on the vapor-liquid-solid growth mechanism, the growth rates of GaAs NWs at 430 °C were 18.2 and 21.5 nm/s for the highest area density obtained of 10- and 20-nm Au NP-catalyzed NWs. The growth rate of the GaAs NWs was reduced with the increase of the NW density due to the competition of precursor materials. High crystal quality of the NWs was also obtained with no observable planar defects. 10-nm Au NP-induced NWs exhibit wurtzite structure whereas zinc-blende is observed for 20-nm NW samples. Controllable density and high crystal quality of the GaAs NWs on ITO demonstrate their potential application in hybrid a solar cell. PMID:26487507

  3. Physiological roles of the transient outward current Ito in normal and diseased hearts.

    PubMed

    Cordeiro, Jonathan M; Calloe, Kirstine; Aschar-Sobbi, Roozbeh; Kim, Kyoung-Han; Korogyi, Adam; Occhipinti, Dona; Backx, Peter H; Panama, Brian K

    2016-01-01

    The Ca(2+)-independent transient outward K(+) current (I(to)) plays a critical role in underlying phase 1 of repolarization of the cardiac action potential and, as a result, is central to modulating excitation-contraction coupling and propensity for arrhythmia. Additionally, I(to) and its molecular constituents are consistently reduced in cardiac hypertrophy and heart failure. In this review, we discuss the physiological role of I(to) as well as the molecular basis of this current in human and canine hearts, in which I(to) has been thoroughly studied. In particular, we discuss the role of Ito; in the action potential and the mechanisms by which I(to) modulates excitation-contraction coupling. We also describe the effects of mutations in the subunits constituting the Ito channel as well as the role of I(to) in the failing myocardium. Finally, we review pharmacological modulation of I(to) and discuss the evidence supporting the hypothesis that restoration of I(to) in the setting of heart failure may be therapeutically beneficial by enhancing excitation-contraction coupling and cardiac function. PMID:26709904

  4. The Study of Simulated Space Radiation Environment Effect on Conductive Properties of ITO Thermal Control Materials

    NASA Astrophysics Data System (ADS)

    Wei-Quan, Feng; Chun-Qing, Zhao; Zi-Cai, Shen; Yi-Gang, Ding; Fan, Zhang; Yu-Ming, Liu; Hui-Qi, Zheng; Xue, Zhao

    In order to prevent detrimental effects of ESD caused by differential surface charging of spacecraft under space environments, an ITO transparent conductive coating is often deposited on the thermal control materials outside spacecraft. Since the ITO coating is exposed in space environment, the environment effects on electrical property of ITO coatings concern designers of spacecraft deeply. This paper introduces ground tests to simulate space radiation environmental effects on conductive property of ITO coating. Samples are made of ITO/OSR, ITO/Kapton/Al and ITO/FEP/Ag thermal control coatings. Simulated space radiation environment conditions are NUV of 500ESH, 40 keV electron of 2 × 1016 е/cm2, 40 keV proton of 2.5 × 1015 p/cm2. Conductive property is surface resistivity measured in-situ in vacuum. Test results proved that the surface resistivity for all ITO coatings have a sudden decrease in the beginning of environment test. The reasons for it may be the oxygen vacancies caused by vacuum and decayed RIC caused by radiation. Degradation in conductive properties caused by irradiation were found. ITO/FEP/Ag exhibits more degradation than other two kinds. The conductive property of ITO/kapton/Al is stable for vacuum irradiation. The analysis of SEM and XPS found more crackers and less Sn and In concentration after irradiation which may be the reason for conductive property degradation.

  5. Experimental investigation of metallic thin film modification of nickel substrates for chemical vapor deposition growth of single layer graphene at low temperature

    NASA Astrophysics Data System (ADS)

    Aminalragia Giamini, Sigiava; Marquez-Velasco, Jose; Sakellis, Ilias; Tsipas, Polychronis; Kelaidis, Nikolaos; Tsoutsou, Dimitra; Boukos, Nikolaos; Kantarelou, Vasiliki; Xenogiannopoulou, Evangelia; Speliotis, Thanassis; Aretouli, Kleopatra; Kordas, George; Dimoulas, Athanasios

    2016-11-01

    Lowering the growth temperature of single layer graphene by chemical vapor deposition (CVD) is important for its real-life application and mass production. Doing this without compromising quality requires advances in catalytic substrates. It is shown in this work that deposition of Zn and Bi metals modify the surface of nickel suppressing the uncontrollable growth of multiple layers of graphene. As a result, single layer graphene is obtained by CVD at 600 °C with minimum amount of defects, showing substantial improvement over bare Ni. In contrast, Cu, and Mo suppress graphene growth. We also show that graphene grown with our method has a defect density that is strongly dependent on the roughness of the original nickel foil. Good quality or highly defective holey single layer graphene can be grown at will by selecting a smooth or rough foil substrate respectively.

  6. A solution-doped small molecule hole transport layer for efficient ITO-free organic solar cells (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Bormann, Ludwig; Selzer, Franz; Leo, Karl; Mueller-Meskamp, Lars

    2015-10-01

    Indium-tin-oxide-free (ITO-free) organic solar cells are an important, emerging research field because ITO transparent electrodes are a bottleneck for cheap large area devices on flexible substrates. Among highly conductive PEDOT:PSS and metal grids, percolation networks made of silver nanowires (AgNW) with a diameter in the nanoscale show a huge potential due to easy processing (e.g. spray coating), high aspect ratios and excellent electrical and optical properties like 15 Ohm/sq with a transmission of 83.5 % including the substrate. However, the inherent surface roughness of the AgNW film impedes the implementation as bottom electrode in organic devices, especially fully vacuum deposited ones, where often shunts are obtained. Here, we report about the solution processing of a small molecule hole transport layer (s-HTL) comprising N,N'-((Diphenyl-N,N'-bis)9,9,-dimethyl-fluoren-2-yl)-benzidine (BF-DPB, host material) and the proprietary NDP9 (p-dopant) deposited from tetrahydrofuran (THF) as non-halogenated, "green" solvent. We show, that the doping process already takes place in solution and that conductivities, achieved with this process at high doping efficiencies (4 * 10^-4 S/cm at 10 wt% doping concentration), are comparable to thermal co-evaporation of BF-DPB:NDP9 under high vacuum, which is the proven deposition method for doped small molecule films. Applying this s-HTL to AgNW films leads to well smoothened electrodes, ready for application in organic devices. Vacuum-deposited organic p-i-n solar cells with DCV2-5T-Me(3:3):C60 as active layer show a power conversion efficiency of 4.4% and 3.7% on AgNW electrode with 35nm and 90 nm wire diameter, compared to 4.1% on ITO with the s-HTL.

  7. Effect of pyrolytic temperature on the properties of TiO2/ITO films for hydrogen sensing.

    PubMed

    Vijayalakshmi, K; Jereil, S David; Karthick, K

    2015-03-01

    Titanium dioxide (TiO2) thin films were prepared on ITO (222) coated glass substrates by spray pyrolysis technique. The influence of substrate temperature on the orientation, phase, vibrational bands and band gap energy of TiO2 films were discussed. The X-ray diffraction patterns of the films revealed preferentially oriented (101) TiO2 anatase phase at the substrate temperature of 300°C and 350°C. Fourier transform infrared spectra of the films showed the significant sharpening of absorption band at ∼645cm(-1) with increase in substrate temperature, which clearly indicates the formation of anatase phase dependent on substrate temperature. Fourier Raman Spectra of the films showed the significant presence of long range order anatase TiO2 phase. The optical measurements of the film prepared at different substrate temperatures revealed the direct band gap of 3.15-3.63eV and indirect band gap of 3.48-3.73eV, characteristic of TiO2 anatase phase. To understand the enhancement of sensing performances of TiO2 films with substrate temperature, the gas sensing mechanism of the films towards 400sccm of hydrogen at room temperature was studied and discussed. PMID:25498820

  8. Solution processed ITO-free organic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    He, Pei; Gu, Cheng; Cui, Qingyu; Guo, Xiaojun

    2011-12-01

    ITO-free organic photovoltaic (OPV) devices with all solution processed transparent anodes of PEDOT:PSS/inkjet printed Ag grid were demonstrated. Through process control, the polymer/metal grid hybrid electrode films are of transparency close to 80% and sheet resistance of 48 ohms/sq. A power efficiency of 1.73% was achieved for the OPV device. The performance can be further improved by process optimization. The technology shows great potential for low-cost manufacturing of OPV solar cells.

  9. The crystallinity and mechanical properties of indium tin oxide coatings on polymer substrates

    SciTech Connect

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2011-02-15

    We present the relationship between the microstructure and mechanical strength of indium tin oxide (ITO) on flexible substrates. With varying thickness (h{sub f}), ITO is deposited on polyethylene terephthalate (PET) by dc magnetron sputtering. The microstructure of ITO is controlled by substrate surface conditions and sputtering parameters. The maximum substrate temperature during deposition is limited to 80 deg. C due to the low glass transition temperature (T{sub g}) of PET. The crystallinity and surface roughness (R{sub rms}) are analyzed by high resolution x-ray diffraction, high resolution transmission electron microscopy, and AFM. The crack resistance of ITO is evaluated by uniaxial tension test. The experimental results reveal that, at a fixed h{sub f}, the degree and quality of crystallinity of ITO are highly improved by increasing sputtering power and the substrate temperature. As the crystallinity is improved, the ratio of preferred growth orientations of (222) to (400) is increased and the degree of peak shifts to lower 2{theta} is decreased. They indicate that the crystallinity is improved as the lattice damage is reduced and film density is increased. The tension test results confirm that, up to a certain h{sub f}, the strength of ITO can be significantly enhanced by improving the microstructures.

  10. The crystallinity and mechanical properties of indium tin oxide coatings on polymer substrates

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2011-02-01

    We present the relationship between the microstructure and mechanical strength of indium tin oxide (ITO) on flexible substrates. With varying thickness (hf), ITO is deposited on polyethylene terephthalate (PET) by dc magnetron sputtering. The microstructure of ITO is controlled by substrate surface conditions and sputtering parameters. The maximum substrate temperature during deposition is limited to 80 °C due to the low glass transition temperature (Tg) of PET. The crystallinity and surface roughness (Rrms) are analyzed by high resolution x-ray diffraction, high resolution transmission electron microscopy, and AFM. The crack resistance of ITO is evaluated by uniaxial tension test. The experimental results reveal that, at a fixed hf, the degree and quality of crystallinity of ITO are highly improved by increasing sputtering power and the substrate temperature. As the crystallinity is improved, the ratio of preferred growth orientations of (222) to (400) is increased and the degree of peak shifts to lower 2θ is decreased. They indicate that the crystallinity is improved as the lattice damage is reduced and film density is increased. The tension test results confirm that, up to a certain hf, the strength of ITO can be significantly enhanced by improving the microstructures.

  11. Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzhi; Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin; Hu, Chenglong

    2016-03-01

    Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV-vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C4H9)4N+ under the positive and negative potentials as comparison with the small Li+ ion.

  12. Near-surface oxidized sulfur modifications and self-assembly of thiol-modified aptamer on Au thin film substrates influenced by piranha treatment.

    PubMed

    Thomas, Joseph P; Zhao, Liyan; Ding, Kejian; Heinig, Nina F; Leung, Kam Tong

    2012-11-01

    Self-assembly of thiol-modified oligonucleotides on Au films has great importance for biosensor applications. Prior to the self-assembly, a piranha treatment (PT) is commonly used to clean the Au surface. Here we report that near-surface oxidized sulfur modifications on Au thin films by PT for longer than 60 s have serious effects on the self-assembled monolayer (SAM) formation of thiol-modified single-stranded thrombin binding aptamer (s-TBA), and a PT time of 10-30 s is optimal for s-TBA SAM formation. These results have important implication to SAM formation of biomolecules, especially for the thiol-modified ones where a careful consideration of this key step could significantly enhance the SAM formation and biosensor performance. PMID:23039103

  13. Artificially MoO3 graded ITO anodes for acidic buffer layer free organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Lee, Hye-Min; Kim, Seok-Soon; Kim, Han-Ki

    2016-02-01

    We report characteristics of MoO3 graded ITO anodes prepared by a RF/DC graded sputtering for acidic poly(3,4-ethylene dioxylene thiophene):poly(styrene sulfonic acid) (PEDOT:PSS)-free organic solar cells (OSCs). Graded sputtering of the MoO3 buffer layer on top of the ITO layer produced MoO3 graded ITO anodes with a sheet resistance of 12.67 Ω/square, a resistivity of 2.54 × 10-4 Ω cm, and an optical transmittance of 86.78%, all of which were comparable to a conventional ITO anode. In addition, the MoO3 graded ITO electrode showed a greater work function of 4.92 eV than that (4.6 eV) of an ITO anode, which is beneficial for hole extraction from an organic active layer. Due to the high work function of MoO3 graded ITO electrodes, the acidic PEDOT:PSS-free OSCs fabricated on the MoO3 graded ITO electrode exhibited a power conversion efficiency 3.60% greater than that of a PEDOT:PSS-free OSC on the conventional ITO anode. The successful operation of PEDOT:PSS-free OSCs indicates simpler fabrication steps for cost-effective OSCs and elimination of interfacial reactions caused by the acidic PEDOT:PSS layer for reliable OSCs.

  14. Modulation of the axial water hydrogen-bonding properties by chemical modification of the substrate in resting state, substrate-bound heme oxygenase from Neisseria meningitidis; Coupling to the distal H-bond network via ordered water molecules

    PubMed Central

    Ma, Li-Hua; Liu, Yangzhong; Zhang, Xuhong; Yoshida, Tadashi; Langry, Kevin C.; Smith, Kevin M.; La Mar, Gerd N.

    2008-01-01

    The hydrogen bonding of ligated water in ferric, high-spin, resting-state substrate complexes of heme oxygenase from Neisseria meningitidis has been systematically perturbed by variable electron-withdrawing substituents on the hemin periphery. The pattern of 1H NMR-detected dipolar shifts due to the paramagnetic anisotropy is strongly conserved among the four complexes, with the magnitude of dipolar shifts or anisotropy increasingly in the order of substituent formyl < vinyl < methyl. The magnetic anisotropy is axial and oriented by the axial Fe-His23 bond, and, while individual anisotropies have uncertainties of ~5%, the relative values of Δχ (and the zero-field splitting constant, D ∝ Δχax) are defined to 1%. The unique changes in the axial field strength implied by the variable zero-field splitting are in accord with expectations for the axial water serving as a stronger H-bond donor in the order of hemin substituents formyl > vinyl > methyl. These results establish the axial anisotropy (and D) as a sensitive probe of the H-bonding properties of a ligated water in resting-state, substrate complexes of heme oxygenase. Correction of observed labile proton chemical shifts for paramagnetic influences indicates that Gln49 and His53, some ~10Å from the iron, sense the change in the ligated water H-bonding to the three non-ligated ordered water molecules that link the two side chains to the iron ligand. The present results augur well for detecting and characterizing changes in distal water H-bonding upon mutagenesis of residues in the distal network of ordered water molecules and strong H-bonds. PMID:16683803

  15. The effect of substrate temperature on the microstructural, electrical and optical properties of Sn-doped indium oxide thin films

    NASA Astrophysics Data System (ADS)

    Raoufi, Davood; Taherniya, Atefeh

    2015-06-01

    In this work, Sn doping In2O3 (ITO) thin films with a thickness of 200 nm were deposited on glass substrates by electron beam evaporation (EBE) method at different substrate temperatures. The crystal structure of these films was studied by X-ray diffraction technique. The sheet resistance was measured by a four-point probe. Van der Pauw method was used to measure carrier density and mobility of ITO films. The optical transmittance spectra were recorded in the wavelength region of 300-800 nm. Scanning electron microscope (SEM) has been used for the surface morphology analysis. The prepared ITO films exhibited body-centered cubic (BCC) structure with preferred orientation of growth along the (2 2 2) crystalline plane. The grain size of the films increases by rising the substrate temperature. Transparency of the films, over the visible light region, is increased with increasing the substrate temperature. It is found that the electrical properties of ITO films are significantly affected by substrate temperature. The electrical resistivity decreases with increasing substrate temperature, whereas the carrier density and mobility are enhanced with an increase in substrate temperature. The evaluated values of energy band gap Eg for ITO films were increase from 3.84 eV to 3.91 eV with increasing the substrate temperatures from 200 °C to 500 °C. The SEM micrographs of the films revealed a homogeneous growth without perceptible cracks with particles which are well covered on the substrate.

  16. Investigation of ITO free transparent conducting polymer based electrode

    NASA Astrophysics Data System (ADS)

    Sharma, Vikas; Sapna, Sachdev, Kanupriya

    2016-05-01

    The last few decades have seen a significant improvement in organic semiconductor technology related to solar cell, light emitting diode and display panels. The material and structure of the transparent electrode is one of the major concerns for superior performance of devices such as OPV, OLED, touch screen and LCD display. Commonly used ITO is now restricted due to scarcity of indium, its poor mechanical properties and rigidity, and mismatch of energy levels with the active layer. Nowadays DMD (dielectric-metal-dielectric) structure is one of the prominent candidates as alternatives to ITO based electrode. We have used solution based spin coated polymer layer as the dielectric layer with silver thin film embedded in between to make a polymer-metal-polymer (PMP) structure for TCE applications. The PMP structure shows low resistivity (2.3 x 10-4Ω-cm), high carrier concentration (2.9 x 1021 cm-3) and moderate transparency. The multilayer PMP structure is characterized with XRD, AFM and Hall measurement to prove its suitability for opto-electronic device applications.

  17. Host plant-dependent metabolism of 4-hydroxybenzylglucosinolate in Pieris rapae: substrate specificity and effects of genetic modification and plant nitrile hydratase.

    PubMed

    Agerbirk, Niels; Olsen, Carl Erik; Topbjerg, Henrik Bak; Sørensen, Jens Christian

    2007-11-01

    After ingestion of transgenic Arabidopsis thaliana CYP79A1 containing sinalbin (4-hydroxybenzylglucosinolate) due to genetic modification, only one major sinalbin-derived sulphate ester (the sulphate ester of 4-hydroxyphenylacetonitrile) was excreted by Pieris rapae caterpillars (corresponding to 69mol% of ingested sinalbin). An additional sulphate ester (the sulphate ester of 4-hydroxyphenylacetamide) was excreted when the caterpillars were reared on two plant species (Sinapis alba and Sinapis arvensis) that contained sinalbin naturally. Artificial addition of sinalbin to S. arvensis leaves resulted in increased levels of the sulphated amide, and an enzymatic activity (nitrile hydratase) explaining the formation of the sulphated amide from sinalbin was detected in both Sinapis species, but not in A. thaliana. In agreement with the suggested minor metabolic pathway, the caterpillars were able to sulphate 4-hydroxyphenylacetamide offered as part of an artificial diet. In fact, phenol and seven para-substituted phenol derivatives with substituents of moderate size were sulphated and excreted, but all tested phenols devoid of a nitrile functional group were less efficiently sulphated than the primary sinalbin detoxification product, 4-hydroxyphenylacetonitrile. This suggests that the specificity of the sulphation step involved in sinalbin metabolism may be adapted to nitriles formed as metabolites of phenolic glucosinolates. On the contrary, there was no specificity for products (4-hydroxybenzylascorbigen and 4-hydroxybenzylalcohol) derived from the semistable isothiocyanate produced from sinalbin in the absence of nitrile specifier protein. PMID:17916498

  18. Modification of calcite crystal morphology by designed phosphopeptides and primary structures and substrate specifities of the cysteine proteases mexicain and chymomexicain

    NASA Astrophysics Data System (ADS)

    Lian, Zhirui

    In order to better understand the mechanism of biomineralization, we have undertaken to synthesize polypeptide model compounds of well-defined structure that can interact with specific faces of calcite and alter its crystal morphology. These peptides were designed based on the structure of alpha-helical winter flounder antifreeze polypeptide HPLC-6. In these peptides, from one to three of the threonine residues in HPLC-6 were substituted by phosphoserine or phosphotyrosine. CD spectra show that all the peptides have virtually the same alpha-helicity, i.e., about 90% at 4°C and 50% at 25°C. However, only peptides which contain at least two phosphate groups spaced 16.8-A apart can modify the crystal morphology of the calcite. The newly developed surface has been tentatively identified as the (001) basal face. Molecular modeling indicates that the spacing of phosphate groups allows for a good match with crystal lattice ions on the (001) plane. Another peptide, CBP-3D, in which the three threonine residues in HPLC-6 were substituted by aspartic acids, appears to bind only to {104} rhombohedral faces of calcite. These experiments suggest that conformation and orientation of the binding ligands in the peptide are important factors governing the mutual recognition of crystal surface and proteins. The complete amino acid sequences of the cysteine proteases mexicain and chymomexicain, isolated from the latex of the plant Pileus mexicanus , were determined by Edman degradation of proteolytic fragments. Mexicain and chymomexicain show-high sequence homology to the papain family of cysteine protease. Mexicain and chymomexicain are monomeric polypeptides, with molecular masses of 23,762 Da and 23,694 Da, respectively, and both contain three deduced disulfide bonds. The proteolytic substrate specificities of mexicain and chymomexicain were studied by digesting a series of synthetic peptides and analyzing the fragments by mass spectrometry. The two proteases showed virtually

  19. A three-dimensional metal grid mesh as a practical alternative to ITO

    NASA Astrophysics Data System (ADS)

    Jang, Sungwoo; Jung, Woo-Bin; Kim, Choelgyu; Won, Phillip; Lee, Sang-Gil; Cho, Kyeong Min; Jin, Ming Liang; An, Cheng Jin; Jeon, Hwan-Jin; Ko, Seung Hwan; Kim, Taek-Soo; Jung, Hee-Tae

    2016-07-01

    The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (~350 nm) and thin (~30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential requirements of transparent electrodes for practical applications in future opto-electronics: excellent optoelectronic performance (a sheet resistance of 9.8 Ω □-1 with a transmittance of 85.2%), high stretchability (no significant change in resistance for applied strains <15%), a sub-micrometer mesh period, a flat surface (a root mean square roughness of approximately 5 nm), no haze (approximately 0.5%), and strong adhesion to polymer substrates (it survives attempted detachment with 3M Scotch tape). Such outstanding properties are attributed to the unique substrate-embedded 3D structure of the electrode, which can be obtained with a high aspect ratio and in high resolution over large areas with a simple process. As a demonstration of its suitability for practical applications, our transparent electrode was successfully tested in a flexible touch screen panel. We believe that our approach opens up new practical applications in wearable electronics.The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (~350 nm) and thin (~30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential

  20. Role of ITO electrode in the resistive switching behavior of TiN/HfO2/ITO memory devices at different annealing temperatures

    NASA Astrophysics Data System (ADS)

    Ye, Cong; Deng, Teng-fei; Wu, Jiaji; Zhan, Chao; Wang, Hao; Zhang, Jun

    2015-05-01

    TiN/HfO2/ITO memory devices were fabricated and annealed at 200, 300, and 400 °C. At room temperature (RT), 200 °C, and 300 °C, the devices show the self-compliance phenomenon and a low SET voltage of 0.2 V, while at 400 °C the SET voltage increases to 1.1 V and the low resistance state (LRS) current increases to 8 mA. We deduced that the impact of annealing temperature on the resistive switching behavior is mainly attributed to the indium tin oxide (ITO) electrode. Some Sn4+ ions in the ITO electrode drift towards the HfO2 layer owing to the electrical force, then an interfacial layer is formed and acts as an internal resistor. At 400 °C, the remarkable increase of LRS current is attributed to the decreases in both the ITO electrode resistance and the interface resistance.

  1. Fabrication and characterization of ITO/silicon SIS solar cells. Final report, October 1, 1978-April 30, 1980

    SciTech Connect

    DuBow, J. B.

    1980-06-01

    The objectives of this research were to optimize the performance of ITO/polycrystalline silicon solar cells, identify performance limitations, identify major stability problems which would inhibit terrestrial application of these devices, evaluate the impact of indium supply and price on terrestrial applications, and evaluate the economic viability of ITO sputter deposited solar cells. These goals were successfully achieved during the course of this multipronged effort. Both area scaling with efficiency maintenance were achieved by process modifications including surface preparation and in-situ passivation techniques. Indium tin oxide on Wacker polycrystalline silicon solar cells were fabricated which achieved 13.7% efficiency for 11 cm/sup 2/ devices. Typical open circuit voltages were 0.525 volts, short circuit currents, 34 mA/cm/sup 2/, and fill factors of 0.75. In the course of this project, three device measurement techniques which assisted in improving cell efficiency and which have broad applicability to all photovoltaic devices were introduced. These were automated admittance and surface state analysis, noise spectral density analysis, and automated I-V and C-V analysis. These measurements were combined with Auger/ESCA, EBIC and flying spot scanner, and other measurement techniques to identify grain boundaries, intragrain defects, edge leakage, and interface losses which were subsequently alleviated through process improvements. It is concluded from this work that prototype production of cells and modules based on this technology would be warranted in the near term.

  2. (110)-oriented indium tin oxide films grown on m- and r-plane sapphire substrates

    NASA Astrophysics Data System (ADS)

    Chern, Ming-Yau; Lu, Tso-Wen; Xu, Wei-Lun

    2015-04-01

    Indium tin oxide (ITO) thin films have been deposited by pulsed laser deposition on m-plane (100) and r-plane (012) sapphire substrates. For both substrates, the films were grown with their [110] direction perpendicular to the substrate planes under the conditions of high growth temperature and high oxygen pressure. Their in-plane epitaxial relations with the substrates were identified to be ITO[001] ∥ Al2O3[020] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[001] for the m-plane substrate. For the r-plane substrate, two types of lattice matching were observed: one being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[2,1, - 1/2] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[4/3, - 4/3,2/3], the other being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[1, - 1,1/2] and \\text{ITO}[1\\bar{1}0]/\\text{Al}2\\text{O}3[8/3,4/3, - 2/3]. The electrical properties were measured by the Hall effect and van der Pauw methods at room temperature. All of the samples have low electrical resistivity on the order of 3.0 × 10-4 Ω cm, high carrier concentration of about 2.5 × 1020 cm-3, and mobility ranging from 70 to 90 cm2 V-1 s-1.

  3. One-step synthesis of carbon nanosheets converted from a polycyclic compound and their direct use as transparent electrodes of ITO-free organic solar cells

    NASA Astrophysics Data System (ADS)

    Son, Su-Young; Noh, Yong-Jin; Bok, Changsuk; Lee, Sungho; Kim, Byoung Gak; Na, Seok-In; Joh, Han-Ik

    2013-12-01

    Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics.Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics. Electronic supplementary information (ESI) available: Detailed experimental methods; chemical structure and 1H NMR spectra; AFM images; TGA spectra; shunt and series resistances; Raman spectra and optical images; atomic contents of the CNSs. See DOI: 10.1039/c3nr04828d

  4. Comparative study of ITO and FTO thin films grown by spray pyrolysis

    SciTech Connect

    Ait Aouaj, M.; Diaz, R.; Belayachi, A.; Rueda, F.; Abd-Lefdil, M.

    2009-07-01

    Tin doped indium oxide (ITO) and fluorine doped tin oxide (FTO) thin films have been prepared by one step spray pyrolysis. Both film types grown at 400 deg. C present a single phase, ITO has cubic structure and preferred orientation (4 0 0) while FTO exhibits a tetragonal structure. Scanning electron micrographs showed homogeneous surfaces with average grain size around 257 and 190 nm for ITO and FTO respectively. The optical properties have been studied in several ITO and FTO samples by transmittance and reflectance measurements. The transmittance in the visible zone is higher in ITO than in FTO layers with a comparable thickness, while the reflectance in the infrared zone is higher in FTO in comparison with ITO. The best electrical resistivity values, deduced from optical measurements, were 8 x 10{sup -4} and 6 x 10{sup -4} {Omega} cm for ITO (6% of Sn) and FTO (2.5% of F) respectively. The figure of merit reached a maximum value of 2.15 x 10{sup -3} {Omega}{sup -1} for ITO higher than 0.55 x 10{sup -3} {Omega}{sup -1} for FTO.

  5. High-Transparency Sputtered In2O3 and ITO Films Containing Zirconium (Presentation)

    SciTech Connect

    Gessert, T. A.; Yoshida, Y.; Fesenmaier, C. C.; Coutts, T. J.

    2007-10-01

    Our recent investigations have identified a method to produce ITO-like films that are less sensitive to variations in the oxygen-containing deposition ambient. Specifically, we are studying the effect of adding small amounts of Zr to both In2O3 and ITO ceramic sputtering targets.

  6. Dual enzyme mimicry exhibited by ITO nanocubes and their application in spectrophotometric and electrochemical sensing.

    PubMed

    Aneesh, K; Vusa, Chiranjeevi Srinivasa Rao; Berchmans, Sheela

    2016-06-20

    The dual enzyme mimicry (peroxidase/catalase-like activities) exhibited by ITO nanocubes (ITO NCs) was investigated by spectrophotometric and electrochemical methods. The peroxidase mimic was successfully applied for the electrochemical detection of H2O2 and spectrophotometric biosensing of glucose. Further, the detection could be extended to the detection of glucose in real samples. PMID:27285844

  7. Understanding the molecular-level chemistry of water plasmas and the effects of surface modification and deposition on a selection of oxide substrates

    NASA Astrophysics Data System (ADS)

    Trevino, Kristina J.

    2011-12-01

    This dissertation first examines electrical discharges used to study wastewater samples for contaminant detection and abatement. Two different water samples contaminated with differing concentrations of either methanol (MeOH) or methyl tert-butyl ether (MTBE) were used to follow breakdown mechanisms. Emission from CO* was used to monitor the contaminant and for molecular breakdown confirmation through actinometric OES as it can only arise from the carbon-based contaminant in either system. Detection was achieved at concentrations as low as 0.01 ppm, and molecular decomposition was seen at a variety of plasma parameters. This dissertation also explores the vibrational (thetaV), rotational (thetaR) and translational (thetaT) temperatures for a range of diatomic species in different plasma systems. For the majority of the plasma species studied, thetaV are much higher than thetaR and thetaT. This suggests that more energy is partitioned into the vibrational degrees of freedom in our plasmas. The thetaR reported are significantly lower in all the plasma systems studied and this is a result of radical equilibration to the plasma gas temperature. thetaT values show two characteristics; (1) they are less than the thetaV and higher than the theta R and (2) show varying trends with plasma parameters. Radical energetics were examined through comparison of thetaR, thetaT, and thetaV, yielding significant insight on the partitioning of internal and kinetic energies in plasmas. Correlations between energy partitioning results and corresponding radical surface scattering coefficients obtained using our imaging of radicals interacting with surfaces (IRIS) technique are also presented. Another aspect of plasma process chemistry, namely surface modification via plasma treatment, was investigated through characterization of metal oxides (SiOxNy, nat-SiO2, and dep-SiO2) following their exposure to a range of plasma discharges. Here, emphasis was placed on the surface wettability

  8. Very High Output Thermoelectric Devices Based on ITO Nanocomposites

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave; Gregory, Otto J.

    2009-01-01

    A material having useful thermoelectric properties was synthesized by combining indium-tin-oxide (ITO) with a NiCoCrAlY alloy/alumina cermet. This material had a very large Seebeck coefficient with electromotive-force-versustemperature behavior that is considered to be excellent with respect to utility in thermocouples and other thermoelectric devices. When deposited in thin-film form, ceramic thermocouples offer advantages over precious-metal (based, variously, on platinum or rhodium) thermocouples that are typically used in gas turbines. Ceramic thermocouples exhibit high melting temperatures, chemical stability at high temperatures, and little or no electromigration. Oxide ceramics also resist oxidation better than metal thermocouples, cost substantially less than precious-metal thermocouples, and, unlike precious-metal thermocouples, do not exert catalytic effects.

  9. Electrochemical modification of indium tin oxide using di(4-nitrophenyl) iodonium tetrafluoroborate.

    PubMed

    Charlton, Matthew R; Suhr, Kristin J; Holliday, Bradley J; Stevenson, Keith J

    2015-01-20

    Optoelectronic applications often rely on indium tin oxide (ITO) as a transparent electrode material. Improvements in the performance of such devices as photovoltaics and light-emitting diodes often requires robust, controllable modification of the ITO surface to enhance interfacial charge transfer properties. In this work, modifier films were deposited onto ITO by the electrochemical reduction of di(4-nitrophenyl) iodonium tetrafluoroborate (DNP), allowing for control over surface functionalization. The surface coverage could be tuned from submonolayer to multilayer coverage by either varying the DNP concentration or the number of cyclic voltammetry (CV) grafting scans. Modification of ITO with 0.8 mM DNP resulted in near-monolayer surface coverage (4.95 × 10(14) molecules/cm(2)). X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of 4-nitrophenyl (NO2Ph) moieties on the ITO surface through the detection of a NO2 nitrogen signal at 405.6 eV after grafting. Further XPS evidence suggests that the NO2Ph radicals do not bond to the surface indium or tin sites, consistent with modification occurring either through bonding to surface hydroxyl groups or through strong physisorption on ITO. CV in the presence of an electroactive probe and electrochemical impedance spectroscopy (EIS) were used to investigate the electronic effects that modification via DNP has on ITO. Even at submonolayer coverage, the insulating organic films can reduce the current response to ferrocene oxidation and reduction by more than 25% and increase the charge transfer resistance by a factor of 10. PMID:25526354

  10. Surface modification and characterization of electrosprayed Sn-doped In2O3 thin films.

    PubMed

    Koo, Bon-Ryul; Ahn, Hyo-Jin

    2014-12-01

    We synthesized Sn-doped In2O3 (Indium tin oxide, ITO) thin films using electrospray and spin-coating. Scanning electron microscopy, atomic force spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Hall-effect measurement, and UV-vis spectrophotometry measurements were performed to investigate the morphological, structural, chemical, electrical, and optical properties of the electrosprayed ITO films with a sol-layer coating for surface modification. To obtain the optimum performance of the resultant ITO thin films after surface modification, we heat-treated them at four different temperatures of 450 degrees C (sample A), 550 degrees C (sample B), 650 degrees C (sample C), and 750 degrees C (sample D) using microwave heating. Surface modified ITO thin films calcined at 550 degrees C (sample B) using electrospray and spin-coating are observed to have superior resistivity (9.9 x 10(-3) 2 Ω x cm) and optical transmittance (-92.08%) owing to the improved densification of the ITO surface by spin-coating and the formation of uniform ITO thin films by electrospraying. PMID:25971111

  11. Work function of sol gel indium tin oxide (ITO) films on glass

    NASA Astrophysics Data System (ADS)

    Biswas, P. K.; De, A.; Dua, L. K.; Chkoda, L.

    2006-12-01

    Indium tin oxide (ITO) films (physical thickness, 250-560 ± 25 nm) were deposited on soda lime silica (SLS) glass and silica layer coated (˜200 nm physical thickness) SLS glass substrates by sol-gel technique using alcohol based precursors containing different In:Sn atomic percentages, namely, 90:10, 70:30, 50:50, 30:70. Cubic phase of In 2O 3 was observed up to 50 at.% Sn while cassiterite SnO 2 phase was observed for 70 at.% Sn. Work function of the films was evaluated from inelastic secondary electron cutoff of ultraviolet photoelectron spectroscopy (UPS) energy distribution curve (EDC) obtained under two experimental conditions (i) as-introduced (ii) after the cleaning of the surface by sputtering. Elemental distribution and the presence of oxygen containing contaminant and carbon contaminant of the samples were done by XPS analysis under same conditions. The work function changed little due to the presence of surface contaminants. It was in the range, 3.9-4.2 eV (±0.1 eV).

  12. CdTe solar cells on thin molybdenum substrates

    NASA Astrophysics Data System (ADS)

    Matulionis, Ilvydas

    2000-10-01

    We report on the development of Mo/(ZnTe:N)/CdTe/CdS/ITO (inverted structure) solar cells grown by radio frequency sputtering. The 0.1 mm thick molybdenum substrate is lightweight and flexible which is advantageous for both terrestrial and space applications. Conversion efficiencies close to 8 percent have been achieved for 5 square millimeter area devices. The photovoltaic activity has also been observed on similar cells deposited on Mo coated kapton and stainless steel substrates.

  13. Investigation of the Magnetic Properties of Ni-implanted ITO Thin Films

    NASA Astrophysics Data System (ADS)

    Ay, Figen; Aktas, Bekir; Khaibullin, Rustem; Nuzhdin, Vladimir; Rameev, Bulat

    Commercially available ITO thin films on fused silica substrates were implanted with 40 keV Ni+ ions to fluences of (0.5,1.0&1.5) ×1017 ions/cm2 at room temperature. XRR measurements show that the thickness of the implanted films (~ 28.5 nm) does not change noticeably with the fluence, while the surface roughness increases essentially. SEM and EDX studies revealed a highly non-uniform distribution of Ni atoms. Room temperature ferromagnetism was observed in the samples with fluences of (1.0&1.5) ×1017 ions/cm2. VSM hysteresis curves and FMR signal point to the formation of a ferromagnetic near-surface layer in the implanted films due to agglomeration of closely-spaced metal Ni nanoparticles. The filling factor of the Ni ferromagnetic phase in the granular magnetic layer was estimated from the FMR results. Super- and para- magnetic phases were observed in the temperature dependence of magnetization by VSM. Superparamagnetic phase is attributed to the Ni nanoparticles located in deeper regions near the film/substrate interface, while paramagnetic phase is related to the impurity centers. For the samples with fluences of (1.0&1.5) ×1017 ions/cm2 average sizes of the superparamagnetic nanoparticles were calculated from the blocking temperatures TB observed in thermo-magnetic dependences. TÜBITAK, Grant No. 114F359 TÜBITAK / RFBR joint project program, Grant No. 213M524 / 14-02-91374-cT-a. RAS Programme No.32.

  14. Fabrication of Organic Bulk Heterojunction Solar Cells on Flexible Substrates

    NASA Astrophysics Data System (ADS)

    Calderon, Gabriel; Merced-Sanabria, Milzaida; Carradero-Santiago, Carolyn; Vedrine-Pauléus, Josee

    2015-03-01

    The active layer for the organic solar cells fabricated is composed of P3HT:PCBM, poly(3-hexylthiophene) (P3HT) as electron donor and phenyl-C61-butyric acid methyl ester(PCBM) as electron acceptor. These polymers were used due to their promising characteristics for devices such as bulk heterojunction solar devices. We used polyethylene terephthalate (PET) substrates, a highly flexible plastic, with indium tin oxide (ITO) as the transparent conducting anode for the device, and UV lithography technique to pattern the ITO; this is to facilitate multiple devices on a single substrate. The fabrication process for pattern transfer incorporates developing and etching processes. We diluted the HCl and DI water to etch out the ITO. PEDOT:PSS and active layer of P3HT:PCBM were deposited on (3.0 sq-cm) patterned of ITO/PET by spin coating method. The cathode was thermally evaporated with Al. We characterized the device using a sourcemeter. We also simulated portions of the device using PET on graphene as the substrate.

  15. The study of the structural and morphology features of indium tin oxide (ITO) nanostructures

    NASA Astrophysics Data System (ADS)

    Hussain Sofi, Ashaq; Ashraf Shah, Mohammad

    2014-03-01

    Micro sized particles of indium tin oxide (ITO) were reduced to nanosized particles through a simple reaction of indium tin oxide (ITO) and de-ionized water at 210^{\\circ} \\text{C}. The typical average diameters of the as-grown nanoparticles were 80 nm to 110 nm. The phase purity and morphology of the products were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscope (TEM). The possible mechanism of formation of ITO nanoparticles is proposed in brief through a mathematical model.

  16. A Dirac-Dunkl Equation on S 2 and the Bannai-Ito Algebra

    NASA Astrophysics Data System (ADS)

    De Bie, Hendrik; Genest, Vincent X.; Vinet, Luc

    2016-05-01

    The Dirac-Dunkl operator on the two-sphere associated to the Z23 reflection group is considered. Its symmetries are found and are shown to generate the Bannai-Ito algebra. Representations of the Bannai-Ito algebra are constructed using ladder operators. Eigenfunctions of the spherical Dirac-Dunkl operator are obtained using a Cauchy-Kovalevskaia extension theorem. These eigenfunctions, which correspond to Dunkl monogenics, are seen to support finite-dimensional irreducible representations of the Bannai-Ito algebra.

  17. Degradation of Flexible, ITO-Free Oligothiophene Organic Solar Cells.

    PubMed

    Bormann, Ludwig; Nehm, Frederik; Sonntag, Luisa; Chen, Fan-Yu; Selzer, Franz; Müller-Meskamp, Lars; Eychmüller, Alexander; Leo, Karl

    2016-06-15

    We investigate the degradation of organic solar cells based on an oligothiophene (DCV5T-Me) small molecule donor and the acceptor C60. Two different flexible, transparent bottom electrode types are employed: a transparent metal electrode (TME) and silver nanowires (AgNWs). They exhibit high optical transparency up to 86% and a sheet resistance as low as 12Ω/□. Power conversion efficiencies of 7.0%, 5.7%, and 7.2% on TME, AgNWs, and indium tin oxide (ITO, reference) are reached, respectively. The solar cells are protected against moisture ingress utilizing a flexible alumina thin-film, exhibiting water vapor transmission rates down to 3 × 10(-5) g m(-2) day(-1) at 38 °C and 90% relative humidity (RH). Implementation of this ultrabarrier as top and bottom encapsulation enables fabrication of fully flexible devices. A decrease in PCE to 80% of initial values is observed after 1000 ± 50 h on flexible, encapsulated TME but only 20 ± 5 h on AgNWs in a climate of 38 °C/50% RH. Degradation in AgNW-based devices is attributed to electrode decomposition. PMID:27218608

  18. Hypomelanosis of Ito: neurological and psychiatric pictures in developmental age.

    PubMed

    Parisi, L; Di Filippo, T; Roccella, M

    2012-02-01

    Hypomelanosis of Ito (HOI) is a multisystem neurocutaneous disorder. In the described cases, cutaneous manifestations (unilateral or bilateral streaks and swirls of hypomelanosis with regular and confluent borders) and extracutaneous abnormalities are often associated. Extracutaneous abnormalities involve the musculoskeletal system (scoliosis, vertebral anomalies, cranial-facial malformations) and other organs, as well as the central nervous system (CNS). The most significant anomalies of the CNS are psychomotor retardation and cognitive deficit. Autism, epilepsy, language disorders, cerebral malformations (neural migration disorders, cerebral hypoplasia, cortical atrophy, agenesis of the corpus callosum) are sometimes present. Numerous abnormal chromosomal patterns have been observed. HOI is usually a sporadic disorder; though autosomal dominant transmission has been suggested, recessive and X-linked inheritance patterns have also been reported. This study describes five children with HOI presenting with various features of the clinical spectrum of the syndrome. Some of these cases were referred for psychomotor therapy as part of an integrated neuropsychologic and psychomotor treatment support program. In this view, psychomotor treatment aims to promote the emotional-relational component, to overcome rigid divisions, and to integrate learning-related cognitive aspects with psychodynamic concepts. Finally, the goals of psychological and social support are to help the parents accept their child's handicap, understand the child's behavior, plan future pregnancies, and foster an environment for their child's integration. PMID:22350047

  19. ITOS VHRR on-board data compression study

    NASA Technical Reports Server (NTRS)

    Gray, R. M.; Davisson, L. D.

    1975-01-01

    Data compression methods for ITOS VHRR data were studied for a tape recorder record-and playback application. A playback period of 9 minutes was assumed with a nominal 18 minute record period for a 2-to-1 compression ratio. Both analog and digital methods were considered with the conclusion that digital methods should be used. Two system designs were prepared. One is a PCM system and the other is an entropy-coded predictive-quantization, sometimes called entropy-coded DPCM or just DPCM, system. Both systems use data management principles to transmit only the necessary data. Both systems use a medium capacity standard tape recorder from specifications provided by the technical officer. The 10 to the 9th power bit capacity of the recorder is the basic limitation on the compression ratio. Both systems achieve the minimum desired 2 to 1 compression ratio. A slower playback rate can be used with the DPCM system due to a higher compression factor for better link performance at a given CNR in terms of bandwidth utilization and error rate. The report is divided into two parts. The first part summarizes the theoretical conclusions of the second part and presents the system diagrams. The second part is a detailed analysis based upon an empirically derived random process model arrived at from specifications and measured data provided by the technical officer.

  20. Fabrication and characterization of photovoltaic cell with novel configuration ITO/n-CuIn3Se5/p-CIS/In

    NASA Astrophysics Data System (ADS)

    Geethu, R.; Jacob, R.; Sreenivasan, P. V.; Shripathi, T.; S, Okram G.; Philip, R. R.

    2015-02-01

    A novel configuration ITO/n-OVC CuIn3Se5/p-CIS/In solar cell has been fabricated by multisource vacuum co-evaporation technique on soda lime glass substrates. The pn junction is formed with ordered vacancy compound as the n counter part for the p type CuInSe2. The structural, compositional, hall coefficient, optical and electrical properties of the p and n layers have been studied respectively by X-ray diffraction, Energy Dispersive Analysis of X rays, optical absorbance and conductivity measurements. Current density-Voltage measurements enabled the determination of efficiency of the device.

  1. Effect of Ar Ion Beam Pre-Treatment of Poly(ethylene terephthalate) Substrate on the Mechanical and Electrical Stability of Flexible InSnO Films Grown by Roll-to-Roll Sputtering System

    NASA Astrophysics Data System (ADS)

    Choi, Kwang-Hyuk; Kim, Han-Ki

    2013-10-01

    We investigated the effects of Ar ion beam irradiation on a flexible poly(ethylene terephthalate) (PET) substrate as surface pre-treatment method in the roll-to-roll (R2R) sputtering system and its contribution to the electrical durability of flexible InSnO (ITO) electrode upon that the flexible PET substrate under repeated mechanical stresses. It was found that the Ar ion beam irradiation of the flexible PET surface could improve an adhesion between R2R sputter-grown ITO film and the PET substrate. X-ray photoelectron spectroscopy results showed that the Ar ion beam irradiation lead to an increase of hydrophilic functional groups when the working pressure, Ar ion beam power, and exposure time increases. Repetitive bending stresses for the flexible ITO/PET film which fabricated through the surface pre-treatment by Ar ion beam irradiation showed more stable electrical durability than those of ITO films on the wet-cleaned PET substrate due to enhanced interfacial adhesion between the ITO film and PET surface. This suggests that the Ar ion beam pre-treatment before sputtering of ITO film in R2R sputtering system is an effective technique to improve the adhesion between ITO film and PET substrate.

  2. Point contact resistive switching memory based on self-formed interface of Al/ITO

    NASA Astrophysics Data System (ADS)

    Li, Qiuhong; Qiu, Linjun; Wei, Xianhua; Dai, Bo; Zeng, Huizhong

    2016-07-01

    Point contact resistive switching random access memory (RRAM) has been achieved by directly sputtering Al electrodes on indium tin oxide (ITO) conductive glasses. The room-temperature deposited Al/ITO shows an asymmetrical bipolar resistive switching (BRS) behavior after a process of initialization which induces a stable high resistive state (HRS). It might be caused by the in-situ formation of an ultra-thin layer (≈4 nm) at the interface. By comparison, the Al/ITO device after vacuum annealed exhibits typical symmetrical BRS without an initiation or electroforming process. This can be ascribed to the ex-situ thickening of the interfacial layer (≈9.2 nm) to achieve the stable HRS after heat treatment. This work suggests that the self-formed interface of active Al electrode/ITO would provide the simplest geometry to construct RRAM.

  3. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  4. Point contact resistive switching memory based on self-formed interface of Al/ITO

    PubMed Central

    Li, Qiuhong; Qiu, Linjun; Wei, Xianhua; Dai, Bo; Zeng, Huizhong

    2016-01-01

    Point contact resistive switching random access memory (RRAM) has been achieved by directly sputtering Al electrodes on indium tin oxide (ITO) conductive glasses. The room-temperature deposited Al/ITO shows an asymmetrical bipolar resistive switching (BRS) behavior after a process of initialization which induces a stable high resistive state (HRS). It might be caused by the in-situ formation of an ultra-thin layer (≈4 nm) at the interface. By comparison, the Al/ITO device after vacuum annealed exhibits typical symmetrical BRS without an initiation or electroforming process. This can be ascribed to the ex-situ thickening of the interfacial layer (≈9.2 nm) to achieve the stable HRS after heat treatment. This work suggests that the self-formed interface of active Al electrode/ITO would provide the simplest geometry to construct RRAM. PMID:27383005

  5. Development of waterborne oil spill sensor based on printed ITO nanocrystals.

    PubMed

    Koo, Jieun; Jung, Jung-Yeul; Lee, Sangtae; Lee, Moonjin; Chang, Jiho

    2015-09-15

    Oil spill accidents occasionally occur in coastal and ocean environments, and cause critical environmental damage, spoiling the marine habitats and ecosystems. To mitigate the damages, the species and amount of spilled oil should be monitored. In this study, we developed a waterborne oil spill sensor using a printed ITO layer. ITO is a compatible material for salty environments such as oceans because ITO is strong against corrosion. The fabricated sensor was tested using three oils, gasoline, lubricant and diesel, and different oil thicknesses of 0, 5, 10, and 15mm. The results showed that the resistance of the sensor clearly increased with the oil thickness and its electrical resistance. For sustainable sensing applications in marine environments, XRD patterns confirmed that the crystal structure of the ITO sensor did not change and FE-SEM images showed that the surface was clearly maintained after tests. PMID:26162511

  6. Point contact resistive switching memory based on self-formed interface of Al/ITO.

    PubMed

    Li, Qiuhong; Qiu, Linjun; Wei, Xianhua; Dai, Bo; Zeng, Huizhong

    2016-01-01

    Point contact resistive switching random access memory (RRAM) has been achieved by directly sputtering Al electrodes on indium tin oxide (ITO) conductive glasses. The room-temperature deposited Al/ITO shows an asymmetrical bipolar resistive switching (BRS) behavior after a process of initialization which induces a stable high resistive state (HRS). It might be caused by the in-situ formation of an ultra-thin layer (≈4 nm) at the interface. By comparison, the Al/ITO device after vacuum annealed exhibits typical symmetrical BRS without an initiation or electroforming process. This can be ascribed to the ex-situ thickening of the interfacial layer (≈9.2 nm) to achieve the stable HRS after heat treatment. This work suggests that the self-formed interface of active Al electrode/ITO would provide the simplest geometry to construct RRAM. PMID:27383005

  7. Adhesion enhancement of indium tin oxide (ITO) coated quartz optical fibers

    NASA Astrophysics Data System (ADS)

    Wang, Yihua; Liu, Jing; Wu, Xu; Yang, Bin

    2014-07-01

    Transparent conductive indium tin oxide (ITO) film was prepared on optical fiber through a multi-step sol-gel process. The influence of annealing temperature on the adhesion of ITO coated optical fibers was studied. Different surface treatments were applied to improve the adhesion between ITO film and quartz optical fiber. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), UV-vis spectrophotometer and Avometer were used to characterize the morphology, crystal structure and photo-electric properties. A thermal shock test was used to evaluate the adhesion. The result shows that the adhesion between ITO film and quartz optical fiber can be strongly influenced by the annealing process, and optimal adhesion can be acquired when annealing temperature is 500 °C. Surface treatments of ultrasonic cleaning and the application of surface-active agent have effectively enhanced the adhesion and photo-electric properties of indium tin oxide film coated quartz optical fiber.

  8. Transgenerational Authenticity Measurement: A Comment on Ito et al. (2009).

    PubMed

    Giannini, James; Wick, Daniel T

    2016-08-01

    The authors examined their previously published studies of transgenerational authenticity in a Japanese cohort (Ito, Horikoshi, & Kodama). In the previous paper, the authors addressed semantic and semiotic concerns. In this paper, design flaws and statistical flaws are examined. PMID:27401068

  9. Broadband terahertz conductivity and optical transmission of indium-tin-oxide (ITO) nanomaterials.

    PubMed

    Yang, Chan-Shan; Chang, Chan-Ming; Chen, Po-Han; Yu, Peichen; Pan, Ci-Ling

    2013-07-15

    Indium-tin-oxide (ITO) nanorods (NRs) and nanowhiskers (NWhs) were fabricated by an electron-beam glancing-angle deposition (GLAD) system. These nanomaterials are of interests as transparent conducting electrodes in various devices. Two terahertz (THz) time-domain spectrometers (TDS) with combined spectral coverage from 0.15 to 9.00 THz were used. These allow accurate determination of the optical and electrical properties of such ITO nanomaterials in the frequency range from 0.20 to 4.00 THz. Together with Fourier transform infrared spectroscopic (FTIR) measurements, we found that the THz and far-infrared transmittance of these nanomaterials can be as high as 70% up to 15 THz, as opposed to about 9% for sputtered ITO thin films. The complex conductivities of ITO NRs, NWhs as well films are well fitted by the Drude-Smith model. Taking into account that the volume filling factors of both type of nanomaterials are nearly same, mobilities, and DC conductivities of ITO NWhs are higher than those of NRs due to less severe carrier localization effects in the former. On the other hand, mobilities of sputtered ITO thin films are poorer than ITO nanomaterials because of larger concentration of dopant ions in films, which causes stronger carrier scattering. We note further that consideration of the extreme values of Re{σ} and Im{σ} as well the inflection points, which are functions of the carrier scattering time (τ) and the expectation value of cosine of the scattering angle (γ), provide additional criteria for accessing the accuracy of the extraction of electrical parameters of non-Drude-like materials using THz-TDS. Our studies so far indicate ITO NWhs with heights of ~1000 nm show outstanding transmittance and good electrical characteristics for applications such as transparent conducting electrodes of THz Devices. PMID:23938519

  10. Influence of defects and processing parameters on the properties of indium tin oxide films on polyethylene napthalate substrate

    SciTech Connect

    Han, H.; Zoo, Yeongseok; Bhagat, S. K.; Lewis, J. S.; Alford, T. L.

    2007-09-15

    Indium tin oxide (ITO) thin films were deposited on polyethylene napthalate (PEN) by rf sputtering using different rf powers (60 and 120 W) and at different substrate temperatures (room temperature and 100 deg. C). Selected PEN substrates were pretreated using an Ar plasma before ITO sputter deposition. Rutherford backscattering spectrometry was used to determine the oxygen content in the films. Hall effect measurements were used to evaluate the electrical properties. In this paper the influence of defect structure, sputtering conditions, and the effect of annealing on the electrical and optical properties of ITO on PEN have been investigated. Electrical properties such as carrier concentration, mobility, and resistivity of the ITO films varied with rf power and substrate temperature. The electrical and optical properties of the films changed after annealing in air. This study also describes how the as-deposited amorphous ITO changes from amorphous to crystalline as a result of heat treatment, and investigates the effects of Sn defect clustering on electrical and optical properties of the ITO films.