Composition and process for preparing transparent conducting film

A process for preparing a transparent conducting film, which comprises coating a substrate with a composition comprising an indium compound, a tin compound, and a solvent as essential components, the tin compound being a compound represented by the following general formula:

• (R).sub.a Sn(NO.sub.3).sub.b (X).sub.4-a-b ( 1)
• wherein R is an alkyl group having 1 to 4 carbon atoms, X is a hydroxyl group, a halogen atom or a carboxyl group, and a and b are integers of 1.about.3 and a+b.ltoreq.4, the indium compound and the tin compound represented by the general formula (1) being in a mixing ratio of the indium compound to the indium compound plus the tin compound of 5-20% by weight in terms of Sn/(In+Sn).times.100, and total of the indium compound and the tin compound represented by the general formula (1), and the solvent being in a proportion of 2 to 80% by weight of the total of the indium compound and the tin compound represented by the general formula (1) and 98 to 20% by weight of the solvent, subjecting the coated substrate to at least one of drying and ultraviolet irradiation at a substrate temperature of 200.degree. C. or higher, when required, and then heating the substrate at a temperature of 400.degree. C. or higher.