Rational Cationic Disorder in Hexagonal Cesium Tungsten Bronze Nanoparticles for Infrared Absorption Materials

Abstract

Hexagonal cesium tungsten bronze (Cs 0.33 WO 3 ) nanoparticles (NPs) have attracted attention for their potential applications in near-infrared (NIR) absorbing materials. However, the insufficient Cs doping in Cs 0.33 WO 3 NPs has limited their NIR absorbing capabilities and practical stability. In this study, we demonstrate the transition pathway from intermediate W-defective Cs 0.33 WO 3 NPs synthesized by flame spray pyrolysis to cationic (Cs, W)-disordered Cs 0.33 WO 3 NPs prepared through appropriate heat treatments. Direct atomic observations reveal the basal shear and prismatic (Cs, W)defective planes, which contributed to the disorder of full Cs doping in Cs 0.33 WO 3 NPs. The obtained Cs 0.33 WO 3 NPs with cationic disorder exhibited enhanced practical performance compared with conventional Cs 0.33 WO 3 NPs. Therefore, the developed approach that regulates cationic disorder enables the rational design of defective metal oxides for a variety of applications, including NIR absorbing materials.