Indium/tin oxide

Figure C1.5.12.(A) Fluorescence decay of a single molecule of cresyl violet on an indium tin oxide (ITO) surface measured by time-correlated single photon counting. The solid line is tire fitted decay, a single exponential of 480 5 ps convolved witli tire instmment response function of 160 ps fwiim. The decay, which is considerably faster tlian tire natural fluorescence lifetime of cresyl violet, is due to electron transfer from tire excited cresyl violet (D ) to tire conduction band or energetically accessible surface electronic states of ITO. (B) Distribution of lifetimes for 40 different single molecules showing a broad distribution of electron transfer rates. Reprinted witli pennission from Lu andXie [1381. Copyright 1997 American Chemical Society.

Another growing apphcation that overlaps the electrically functional area is the use of transparent conductive coatings or tin oxide, indium—tin oxide, and similar materials in photovoltaic solar ceUs and various optic electronic apphcations (see Photovoltaic cells). These coatings are deposited by PVD techniques as weU as by spray pyrolysis, which is a CVD process. 

Spray Pyrolysis. In spray pyrolysis, a chemical solution is sprayed on a hot surface where it is pyrolyzed (decomposed) to give thin films of either elements or, more commonly, compounds (22). Eor example, to deposit CdS, a solution of CdCl plus NH2CSNH2 (thiourea) is sprayed on a hot surface. To deposit Iu202, InCl is dissolved in a solvent and sprayed on a hot surface in air. Materials that can be deposited by spray pyrolysis include electrically conductive tin—oxide and indium/tin oxide (ITO), CdS, Cu—InSe2, and CdSe. Spray pyrolysis is an inexpensive deposition process and can be used on large-area substrates. 

Dyes for Color Filters. Colorhquid crystal display systems consist of LSI drivers, glass plates, polarizers, electrodes (indium—tin oxide), and microcolor filters. The iadependent microcolor filter containing dyes is placed on each Hquid crystal pixel addressed electrically and acts as an iadividual light switch. All colors can be expressed by the light transmitted through each filter layer of the three primary colors, ie, red, green, and blue (Fig. 12). 

Fig. 12. General stmcture of LCD. A, polarizer plate B, glass plate C, electrodes (indium—tin oxide) D, Hquid crystal E, common electrode (ITO) F, overcoated layer G, colored pixel H, back light. In an improved color LCD system today, retardation films are placed between A and B.

The changes in the optical absorption spectra of conducting polymers can be monitored using optoelectrochemical techniques. The optical spectmm of a thin polymer film, mounted on a transparent electrode, such as indium tin oxide (ITO) coated glass, is recorded. The cell is fitted with a counter and reference electrode so that the potential at the polymer-coated electrode can be controlled electrochemically. The absorption spectmm is recorded as a function of electrode potential, and the evolution of the polymer s band stmcture can be observed as it changes from insulating to conducting (11). 

Figure 9-3. Conventional multilayer light emission device (LED) indium tin oxide (ITO) electrode on a substrate, active layers A (hole transport), B (emitter), C (electron transport), and a niclat electrode. A possible encapsulation layer has been omitted, which would prevent the conjugated molecules from photo-oxidation.

Currem field characteristics measured wiih conjugated polymers sandwiched between an indium-tin oxide (ITO) anode and an aluminum cathode are usually hole dominated and are, consequently, appropriate for testing injection/lransport models for the case of unipolar current How. Data shown in Figure 12-1 refer to injection-limited currents recorded on typically 100 nm thick spin-coated films of derivatives of poly(y d/"fi-phenylenevinylene) (PPV) and a planarized poly(/ /" -pheny-leue) employing a Keilhley source measure unit. The polymers were ... 

Most 2,5-unsubstituted pyrroles and thiophenes, and most anilines can be polymerized by electrochemical oxidation. For pyrroles, acetonitrile,54 or aqueous55 electrolyte solutions are normally used, while the polymerization of thiophenes is performed almost exclusively in nonaqueous solvents such as acetonitrile, propylene carbonate, and benzonitrile. 0 Polyanilines are generally prepared from a solution of aniline in aqueous acid.21 Platinum or carbon electrodes have been used in most work, although indium-tin oxide is routinely used for spectroelectrochemical experiments, and many other electrode materials have also been employed.20,21... 

Sn02 is codeposited with indium oxide to form a compound known as indium tin oxide (ITO), widely used as a transparent conductive film. ITO is usually deposited by sputtering and little work on CVD has been reported. 

Sn02 and indium tin oxide (ITO) for conductive transparent coatings on glass for electromagnetic interference (EMI) applications. 

Quadratic hyperpolarisability DCJTB 4-(Dicyanomethylene)-2-tert-butyl-6 (l,l,7,7-tetrametbyljulolidyl-9-enyl)-4H-pyran Disperse red 1 HOMO-LUMO gap Electroluminescence Indium-tin-oxide Nonlinear optic... 

The photoelectrochemical properties of CdS nanoparticles formed in LB films of cadmium arachidate on ITO glass (indium tin oxide-coated glass) were investigated [188]. The CdS particles were formed by exposure to H2S gas, and then the cadmium arachidate structure was regenerated by exposing the gas-treated films with aqueous solutions of CdCL. Gassing/immersion cycling increased the particle size from 2.3 0.7 nm after one cycle to 9.8 2.4 nm after five cycles. The 9.8-nm particles showed UV-visible ab-... 

FiG. 24 CVs of Langmuir-Schaefer films of cytochrome P450scc on indium-tin oxide glass plate (ITO) in 10 mM phosphate buffer containing 0.1 M KCl at a scan rate of 20 mV/s between 0.4 and -0.6 V vs. Ag/AgCl. 

FIG. 26 Cyclic voltammograms of 40 monolayers of Langmuir-Schaefer films of cytochrome P450SCC on indium-tin oxide glass plate (ITO) in 10 mM phosphate buffer at a scan rate of 20 mV/s between 0.4 and —0.4 V vs. Ag/AgCl. LS films on ITO worked as the working electrode, platinum as the counter, and Ag/AgCl as the reference electrode. Cholesterol dissolved in X-triton 100 was added 50 p.1 at a time (1) with cholesterol, (2) 50 p.1 of cholesterol, (3) 100 p.1 cholesterol, and (4) 150 p.1 of cholesterol. 

Li KW, Meng XT, Liang X, Wang H, Yan H (2006) Electrodeposition and characterization of PbSe films on indium tin oxide glass substrates. J Solid State Electrochem 10 48-53... 

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