The electrochromic properties of tungsten oxide thin films deposited by solution thermolysis

Tungsten oxide thin films were prepared by solution thermolysis (ST-WO,). F ilms were deposited onto fluorine-doped tin oxide (FTO)-coated glass substr ates maintained at 300 degreesC, which were then used as working electrodes in a three-electrode electrochromic (EC) cell. The EC cell configuration w as FTO/WO3/0.1 N H2SO4/C, SCE. Cyclic voltammetry (C-V) was carried out in the potential range -0.7 to +0.7 V (SCE), at different scan rates. The valu es of anodic peak potential and threshold voltage are extracted from C-V. T he diffusion coefficient of H+ ions during intercalation and deintercalatio n are calculated. They are of the order of 10(-12) cm(2)/s. Chronoamperomet ric (C-A) studies were carried out at different double potential steps and response times are calculated. The films before and after colouration were further characterized by optical absorption technique. The colouration effi ciency at 633 nm is 25 cm(2)/C. The ST-WO3 films were found to be stable in 0.1 N H2SO4 up to 2X10(3) cycles. (C) 2000 Elsevier Science B.V. All right s reserved.