Rational modification in the photochromic and self-bleaching performance of hierarchical microsphere Cu@h-WO3/WO3•nH2O composites

Herein, we used a self-assembly method to synthesize novel Cu@h-WO3/WO3 center dot nH(2)O hierarchical microsphere composites with enhanced photochromism and self-bleaching performance. The composite fabricated with 1.0% Cu-WO displayed a rapid change from light-yellow to dark-gray after 2 min of ultraviolet irradiation and self -bleached in less than 1 h in the dark. Composite samples were characterized to investigate changes in their morphology and structure after being doped with different amounts of Cu. The hierarchical microspheres were composed of small, well-dispersed nanorods that provided active sites capable of absorbing light. Ensuring the proper Cu content in the WO3 lattice promoted the separation of carriers through interfacial charge transfer (IFCT) and prevented the recombination of electron-hole pairs due to excessive doping. Combing hexagonal WO3 with WO3 center dot nH(2)O and Cu provided unobstructed channels, proton sources, and interactions with W species, which improved the efficiency of proton insertion and extraction. The WO3 hybrid materials described in this research displayed high coloration efficiencies and reversibility and may find applications in solar energy devices.