Indium tin oxide ITO

Polishing the thin-fitm electrodes is not practical due to the thinness of these layers and the mechanical damage caused by polishing. 

Another cleaning routinely used is washing the ITO surface with a solution of Triton X-100 (a surfactant) and water (140, 144). Other surfactant solutions might also be used for washing the surface. This is followed up by ultrasonic washing in ultrapure water and ethanol for at least 10 min each. 

The same authors reported an RCA treatment that involved heating the ITO in a 1 1 5 solution of NH4OH/H2O2/H2O for 30 min at 80 °C. This was followed by a thorough rinsing with ultrapure water and drying with a stream of nitrogen gas. 

Cleaning by an air plasma treatment can be accomplished using a standard Harrick plasma cleaner (Model PDC-32G) at 60 W and 100-200 mTorr for 15 min. The samples should first be solvent cleaned as described above. 

ITO can also be cleaned and activated by vacuum heat treatment. The treatment should be performed in a vacuum that is relatively free of residual oxygen. Relatively low temperatures should be used to avoid desorbing the ITO film from the substrate or decomposing 

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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.

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. 

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 ... 

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. 

Very recently a new kind of electrocatalyst has been propounded using the dinuclear quinone-containing complex of ruthenium (25).492,493 Controlled-potential electrolysis of the complex at 1.70 V vs. Ag AgCl in H20 + CF3CH2OH evolves dioxygen with a current efficiency of 91% (21 turnovers). The turnover number of 02 evolution increases up to 33,500 when the electrolysis is carried out in water (pH 4.0) with an indium-tin oxide(ITO) electrode to which the complex is bound. It has been suggested that the four-electron oxidation of water is achieved by redox reactions of not only the two Run/Ruin couples, but also the two semiquinone/quinone couples of the molecule. 

Very recently, even transparent conducting oxides (TCOs), such as indium-tin-oxide (ITO), have been prepared using suitable KLE templates.59 As one potential application, such porous TCOs (ZnO, etc.) are interesting for use in dye-sensitized solar cells. In general, such porous electrodes cover a variety of potential electro-optical applications, because they are both conducting and transparent. 

The method uses a simple electrode made of a thin film of sol-gel organosilica doped with nitroxyl radicals deposited on the surface of an indium tin oxide (ITO) electrode. Thus, whereas in water benzyl alcohol is rapidly oxidized to benzoic acid, the use of the hydrophobic sol-gel molecular electrode TEMPO DE affords benzaldehyde only (Figure 1.9), with an unprecedented purity, which is highly desirable for the fragrance and pharmaceutical industries where this aromatic aldehyde is employed in large amounts. 

L.J. Meng and M.P. dos Santos, Properties of indium tin oxide (ITO) films prepared by r.f. reactive magnetron sputtering at different pressures, Thin Solid Films, 303 151-155, 1997. 

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