Deposition spray pyrolysis

Brief summaries of the various processing technologies used in fabricating cell components are given in Section 3.6.9.They include tape-casting, calendering, screen-printing, electrophoretic deposition, electrochemical vapour deposition, chemical vapour deposition, spray-pyrolysis and sol-gel. 

Various procedures for the preparation of 10 03 films and nanoparticles, including evaporation, sputtering, laser deposition, spray pyrolysis, thermal oxidation of predeposited hi and electrochemical deposition have been reported [27], The structural and morphological characterization of lri203-based materials has been carried out by... 

Vapor-phase deposition, such as physical or chemical vapor deposition, spray pyrolysis, etc. 

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. 

In spray pyrolysis, very fine droplets are sprayed onto a heated substrate. The limitations of this process are the same as for spin-on coating. The same is often the case for preparing solid electrolytes by chemical vapor deposition (CVD) processes, which in addition are more expensive, and the precursors are often very toxic. 

Silver(I) /3-diketonate derivatives have received significant attention due to the ease with which they can be converted to the elemental metal by thermal decomposition techniques such as metal organic chemical vapor deposition (MOCVD).59 The larger cationic radius of silver(I) with respect to copper(I) has caused problems in achieving both good volatility and adequate stability of silver(I) complexes for the use in CVD apparatus. These problems have been overcome with the new techniques such as super critical fluid transport CVD (SFTCVD), aerosol-assisted CVD (AACVD), and spray pyrolysis, where the requirements for volatile precursors are less stringent. 

Films at NASA GRC were deposited using homemade spray or aerosol-assisted chemical vapor deposition (AACVD) reactors to exploit the lower deposition temperature enabled by the simpler decomposition chemistry for the SSPs.6 9 AACVD is a simple and inexpensive process that offers the advantage of a uniform, large-area deposition, just like metal organic CVD (MOCVD), while also offering the low-temperature solution reservoir typical of spray pyrolysis methods. 

Spray pyrolysis has been utilized to produce both powders of SOFC materials [19] and also SOFC component layers [118-121], Thin (1 pm) coatings have been fabricated by spray pyrolysis [121], with zero gas permeability achieved for some conditions of substrate surface roughness and temperature during deposition, but... 

Xie Y, Neagu R, Hsu CS, Zhang X, and Deces-Petit C. Spray pyrolysis deposition of electrolyte and anode for metal-supported solid oxide fuel cell. J. Electrochem. Soc. 2008 155 B407-B410. 

The catalysts were synthesized as films, with ceria prepared by spray pyrolysis of 0.1 M solutions of Ce(N03)3 onto nonporous alumina wafers held at 250 °C. The ceria was then calcined at 300 °C, resulting in a crystallite size of 10 nm. Pt, Pd, or Rh was vapor deposited onto the oxide film. For kinetics testing, the temperature was 300 °C. To determine the reaction order of H20, Pco was maintained constant at 0.026 atm. For the reaction order on CO, Ph2o was maintained constant at 0.02 atm. The kinetic parameters are tabulated in Table 69. 

The photoelectrochemical behavior of a given photoanode is dependent on its method of synthesis. Various methods, some of which we now briefly consider, such as anodic oxidation, spray pyrolysis, reactive sputtering and vapor deposition are commonly employed to make polycrystalline thin films. 

Karadimitra, K., Lorentzou, S., Agrafiotis C., and Konstandopoulos A. G. Modeling of Catalytic Particle Synthesis via Spray Pyrolysis In-Situ Deposition on Porous Materials . PARTEC 2004, International Conference for Particle Technology, Nuremberg, Germany, 2004, March 16-18. 

It is possible to inhibit reaction (5) by employing spray pyrolysis to deposit a compact layer of 2 on the Sn02 substrate before deposition of the nanocrystalline 2 film [9,10]. It is, however, relatively difficult to achieve a pinhole-free film. We chose to investigate the electropolymerization of an insulating film on the exposed parts of the Sn02 after the nanocrystalline 2 film has been depos-... 

Different procedures have been established chemical vapor deposition [5, 16], powder sintering combined with pressing [1, 2, 6, 7, 12, 17-25], sputtering [9, 26], flux and melt grown [10, 27, 28], chemical deposition [11, 14, 29, 30], sol-gel techni-ques [31], mechano-chemical pro-cessing [32], forced hydrolysis [33,34], spray pyrolysis [35-41], and thermal and hydro- thermal oxidation [3, 4, 8, 10, 17,42-58]. 

Spray pyrolysis An appropriate metal salt is sprayed from an atomizer onto a hot substrate where decomposition occurs yielding the metal oxide. There are advantages to be gained by electrically charging the droplets using an electrostatic atomizer Deposition rates are quite low, typically in the range 1-10 /unh-1. 

ZnO thin films can be prepared by a variety of techniques such as magnetron sputtering, chemical vapor deposition, pulsed-laser deposition, molecular beam epitaxy, spray-pyrolysis, and (electro-)chemical deposition [24,74]. In this book, sputtering (Chap. 5), chemical vapor deposition (Chap. 6), and pulsed-laser deposition (Chap. 7) are described in detail, since these methods lead to the best ZnO films concerning high conductivity and transparency. The first two methods allow also large area depositions making them the industrially most advanced deposition techniques for ZnO. ZnO films easily crystallize, which is different for instance compared with ITO films that can... 

Substoichiometric films can be obtained either by substoichiometric growth conditions [10] or by subsequent reduction. Annealing in H2 atmosphere decreases the resistivity considerably for ZnO films deposited by spray pyrolysis [77]. Sputtered ZnO Al films do not show a substantial effect [78],... 

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