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Transparent conducting coatings of sol gel ATO (antimony doped tin oxide) were used to improve surface smoothness of commercial sputter deposited ITO (indium tin oxide) coatings for application as display electrodes. In order to overcome the deteriorating evaporation cooling during dip coating, the coating solution was heated moderately to 25-C thus providing the substrate with the required heat. This way, the surface roughness of the ITO could be reduced with an only 45 nm thick ATO coating to R pv 3.8 nm (R a 0.4 nm) compared to 31 nm (3.8 nm) for the ITO substrate. Another benefit of such additional coating is the possibility to tailor surface properties of the electrodes in wide ranges. This was used to increase the work function of the ITO substrate from initially 4.3 4.6 eV to about 4.8 5.2 eV by the ATO coating.

Transparent conducting coatings of doped SnO 2 and Zn 2 SnO 4 have been deposited by the sol gel technique on borosilicate and alumosilicate glass substrates, respectively. As films of SnO 2 : Sb (ATO) show some intrinsic drawbacks, which are discussed in this report, alternative dopants for SnO 2 such as Ta, Nb and W, were examined concerning the electrical and optical properties of the deposited coatings. In this way, coatings with resistivities on the order of 3 Â 10 À 2 V cm characterized by much higher charge carrier mobilities than for SnO 2 : Sb and a transmission of > 85% were realized. In the search for ternary compounds (A x B y O z), coatings in the system ZnO SnO 2 were examined, focusing on the fabrication of meta zinc stannate (Zn 2 SnO 4). Coatings made from tin alkoxides yielded monophasic materials with high crystallinity and good morphological properties. By post annealing, a resistivity of 0.4 V cm with charge carrier mobilities of up to 7 cm 2 /Vs were obtained. Therefore, the development of the coating solution is as crucial as the elaboration of the heat treatment procedure of as deposited films in order to obtain pure Zn 2 SnO 4 phase coatings without any impurity phases.

A room temperature spraying technique was developed for the deposition of transparent conducting sol-gel ATO (antimony doped tin oxide, SnO :Sb) coatings, based on an 0.2 M solution of SnCl in 1-propanol with 5 mol.% SbCl and a mixture of 2-2 2 3 isopropoxyethanol and 2-butoxyethanol as additives with a low evaporation rate. The selection of solvents and the adjustment of the evaporation rate are crucial to obtain uniform films and to avoid film defects like wetting problems or an orange peel effect. The ATO coatings were spray deposited manually on complex shaped substrates as well as on large area flat substrates with a size up to 21=30 cm by means of an industrial flat spray coater. The resulting ATO coatings are characterised by a thickness 2 of up to 120 nm, a resistivity of approximately 2=10 V cm and a transmission T)85% in the visible, which is similar to the y2 properties obtained for dip coated films.