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

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.