Rapid bleaching of photoelectrochromic device by the simple addition of Pt catalyst in WO3 layer

Abstract

We have developed a transparent conducting oxide (TCO) free photoelectrochromic device with fast kinetics. The device can be colored fully in 3 min and bleach 95% within 30 min in dark. The addition of Pt catalyst in the WO3 layer catalyzes the back reaction in dark. The coloring is not affected by the addition of catalyst on the WO3 layer and the device shows the same amount of coloring as in the reference device. Both devices took 3 min to color completely but bleaching time was improved by a large margin. The reference device which does not have any Pt in WO3 or TiO2 layer takes 24 h to bleach fully compared to 30 min bleaching of Pt added device. The commercial feasibility of the device was checked by making a large area (60x48 cm2) prototype Further the thermal stability of the device was checked by keeping it under thermal stress at 65 °C. It was observed that the device was stable after 300 h. This device paves the way for commercializing the photoelectrochromic windows without the use of external power and transparent conducting oxide.