Electrochemical and electrochromical properties of oxide films are dependent on their microstructure and morphological properties. Thus, the effects of three preparation variables on the electrochemical and electrochromical properties of Nb2O5 thin films prepared by the Pechini method were investigated. In order to minimise the number of experiments, a factorial design 2 3 was used. The effects of the following variables: CA/EG molar ratio, CA/[Nb] molar ratio and calcination temperature were evaluated. Films prepared with the resin composition CA/EG = 1:4, CA/[Nb] = 10:1 and calcined at 500degreesC, showed the highest values of intercalation charge, transmittance variation and coloration efficiency, 22 mC/cm(2), 84% and 23 cm(2) C-1, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.