Studies on spontaneously reduced vanadium pentoxide xerogel coatings for electro-chromic applications

The aging-induced spontaneous reduction of vanadium pentoxide (V2O5) xerogel coatings and its effects on their electro-chromic properties were investigated through optical and electrochemical techniques. The color change could visually confirm the changes in the oxidation states and formation of V4+, which quantitatively reach similar to 25% after three weeks of aging. Here, the xerogel coatings with three different thicknesses were fabricated using sol-electrophoresis. Detailed examination revealed that such self-reduction eventually affects the entire thickness range and considerably decreases the near-surface work function by 0.31-0.36 eV. The coating thicknesses were found to be a dominating factor that controls film morphology, reactivity, and the final opto-electronic response through the formation of midgap-states. The devices made with aged films exhibited relatively better electrochromic performances with higher optical contrast, better coloration efficiency, and faster Li+ intercalation kinetics. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The aging-induced spontaneous reduction of vanadium pentoxide (V2O5) xerogel coatings and its effects on their electrochromic properties were studied. Aging led to the formation of V4+ and a decrease in surface work function, resulting in improved electrochromic performances in terms of optical contrast, coloration efficiency, and Li+ intercalation kinetics.