One-step ball-milling synthesis of cesium tungsten bronze nanoparticles and near-infrared shielding performance

Tungsten bronze (MxWO(3)) materials have been widely used as thermal insulation for architectural glass because of their higher near-infrared (NIR) light shielding capacity. To solve the problems encountered in solvothermal preparation with high costs and low yields, this study has developed a facile, eco-friendly, effective, but low-cost method, with no need for any annealing process, for promoting the large-scale fabrication of cesium tungsten bronze (CsxWO3, x = 0.32) nanomaterials for potential thermal insulation windows applications. In the proposed ball-milling process, the tungstic acid material could be reduced to hydro tungsten bronze (HxWO3) by cellulose, while the cesium ions (Cs+) could be gradually incorporated into the interspace until the formation of Cs0.32WO(3) (Cs/W atomic ratio = 0.32), with an average particle size of similar to 33 nm after a 15 h ball-milling process. The re-action mechanism has been investigated in detail via particle structural analysis and optical performance characterization. The obtained Cs0.32WO3 nanoparticles are dispersed in a solution composed of surfactant (s) and polymer (s) which can form a thin film with a thickness of about 2 mu m on a glass substrate, by a spinning coating or casting method, to exhibit high visible (Vis) light transmittance (T-566nm = 72.6%), and excellent NIR-shielding capability (T-1388nm = 5.3%), reflected by good heat-insulating performance in practice use. This work will pave a new path for large-scale production of Cs0.32WO3 nanomaterials with low costs and high perfor-mance, beneficial for practical applications in energy-saving glass coatings.

Automated summary

This study developed a simple, eco-friendly, effective, and low-cost method for the large-scale fabrication of cesium tungsten bronze (Cs0.32WO3) nanomaterials. The proposed ball-milling process reduced tungstic acid to hydro tungsten bronze (HxWO3) and incorporated cesium ions (Cs+) until the formation of Cs0.32WO3. The obtained Cs0.32WO3 nanoparticles were dispersed in a solution composed of surfactant and polymer, which could form a thin film on a glass substrate with high visible light transmittance and excellent NIR-shielding capability.