Controlling the growth of hexagonal CsxWO3 nanorods by Li+-doping to further improve its near infrared shielding performance

In order to develop a novel high efficient energy-saving film, Li, Cs co-doped tungsten bronze (Li m Cs n WO 3 , m + n = 0.35) nanoparticles with excellent near-infrared (NIR) shielding properties were prepared by a facile solid state reaction method. It has been clarified that Li + -doping can control the crystal growth of Cs x WO 3 , resulting in formation of hexagonal nanorods with high aspect ratio, which is conducive to enhancing the local surface plasmon resonance (LSPR) and improving the NIR shielding performance. The as-prepared Li m Cs n WO 3 films from dispersion of nanoparticles with Li/Cs = 0.2:0.8 could exhibit excellent transparent heat shielding performance with the maximum visible light transmittance 75.18% and NIR shielding rate 97.65%. Moreover, the temperature difference between the outside surface and air in the box for the film glass during the thermal insulation test is 3 times that of ordinary glass. In addition, the regulation mechanism of Li + -doping on the crystal structure and NIR shielding properties were investigated. It is found that the mixed alkali effect in the Li m Cs n WO 3 nanoparticles is favorable for obtaining hexagonal Cs 0·32 WO 3 crystal grains with improved NIR shielding performance and stable crystal structure. This work has great significance for promoting industrial production and practical applications in the field of energy-saving window films. • Li m Cs n WO 3 nanorods were synthesized by a facile solid-state reaction method. • Li, Cs co-doping can lead to the growth of Li m Cs n WO 3 nanorods with high aspect ratio. • The mixed alkali effect is helpful for forming stable hexagonal nanorods. • The Li m Cs n WO 3 nanorods exhibit improved near infrared shielding performance.