Tungsten bronze CsxWO3 nanopowders doped by Ti to enhance transparent thermal insulation ability for energy saving

Cesium tungsten bronze (Cs x WO 3 ), a unique energy-saving material, has attracted great interest because of its excellent visible transmittance and near-infrared absorption. In order to improve its optical properties , the Ti doping modification was carried out in this work, and a series of Ti-doped Cs X WO 3 (Ti-Cs x WO 3 ) nanopowders were synthesized by a solvothermal reaction and post-annealing. The 1.71 at. % of Ti dopants achieved remarkable enhancement of both integral visible transmittance ( T lum , 380–780 nm) and near-infrared shielding efficiency ( Ψ NIR , 780–2500 nm) of Cs x WO 3 . The T lum and Ψ NIR of the 1.71 at. % Ti-Cs x WO 3 polymer film reaches 63.87 % and 76.90 %, respectively, higher by 51.88 % and 65.00 % than those of the Cs x WO 3 film. The improvement of T lum is attributed to the broadening of band gap and smaller size of the nanoparticles induced by Ti doping, and the enhanced Ψ NIR would result from the increased free electron concentration and energy levels of impurities. The incorporation of Ti elements renders Cs x WO 3 a promising application in the field of energy saving.