Supercritical solvothermal synthesis and near-infrared absorbing properties of Cs_x WO₃

Cs_x WO₃ nanoparticles in the range of 2050 nm have been successfully synthesized by the supercritical solvothermal approach, where after dissolving WCl₆ and CsOH in a mixed solution of water, ethanol and oleic acid, the solution was heated at 300°C. The products were characterized by X-ray diffraction, TEM, HR-TEM, EDS, laser particle size analysis and thermographic measurements. Cs_x WO₃ nanoparticles showed the high transparency in the visible region, excellent shielding performance of the near-infrared light and limited reflectance of light in the range of 2002700 nm, indicating the strong absorption of NIR light on the nanosized Cs_x WO₃. Cs_x WO₃ nanoparticles also exhibited quick conversion of photo-energy to local heat.