Simulation of the sublimation process in the preparation of photochromic WO3 film by laser microprobe mass spectrometry

Authors employed a method based on laser microprobe mass spectrometry to simulate the sublimation process of WO3 with conditions mimicing those in vacuum evaporation. Both positive and negative ion clusters containing no more than six W atoms were generated from direct laser vaporization of WO3 powder. The fragment valence calculation on the ion clusters showed that a valence of six was the ideal oxidation state for W. XPS results also confirmed the formation of stoichiometric units in the deposited film. Based on experimental results, (WO3)x, especially (WO3)3 and (WO3)4, were the major component units in the vacuum evaporated (VE) film. 13 refs.