PUB - Publikationen an der Universität Bielefeld

Electrochromism is a reversible effect, for which the transmittance (colour) modulation is induced by an applied external voltage. By changing the polarity, the film returns to its initial state. The low temperature chemical vapour growth processing of thin films of mixed W and Mo oxides is presented. The investigation is related to optimization of the film structure and the related optoelectronic properties as a function of the CVD process parameters. The morphology of the films is determined by SEM microscopy and EDX analysis reveals their compositions. The vibrational properties of the films are investigated by FTIR and Raman spectroscopy. Electrochromic behavior was examined by cyclic voltammetric experiments, performed in a standard three-electrode arrangement. From the cyclic voltammetry data, the optical modulation and colour efficiency (CE) values were estimated. The estimated CE values for a wavelength of 550 nm (the maximum of the solar energy spectrum) are one of the best reported in the literature.