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

Hexagonal cesium tungsten bronze (Cs0.33WO3) nanoparticles (NPs) have attracted attention for their potential applications in near-infrared (NIR) absorbing materials. However, the insufficient Cs doping in Cs0.33WO3 NPs has limited their NIR absorbing capabilities and practical stability. In this study, we demonstrate the transition pathway from intermediate W-defective Cs0.33WO3 NPs synthesized by flame spray pyrolysis to cationic (Cs, W)-disordered Cs0.33WO3 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 Cs0.33WO3 NPs. The obtained Cs0.33WO3 NPs with cationic disorder exhibited enhanced practical performance compared with conventional Cs0.33WO3 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.