Spray-coating of cesium tungsten bronze for improved near-infrared shielding in green energy glass

In this study, an efficient method for synthesizing CsxWO3 nanocrystals using ammonium metatungstate and cesium carbonate as starting materials is developed. Tartaric acid acted as a reducing agent and chloroplatinic acid as a catalyst. Cesium tungsten bronze (CsxWO3) strongly absorbs near-infrared (NIR) light, making it an ideal candidate for energy-efficient building glass. However, due to its high surface energy, inorganic particles tend to agglomerate into larger particles. Ball milling reduces the particle size, and a nonionic surfactant ensured stable dispersion in organic materials. The CsxWO3 nanoparticle solution spray-coated onto glass extremely enhances near-infrared shielding. With a 2 wt% of CsxWO3 nanoparticle solution the solid content, the coated glass shows a 75.52% visible light transmittance, and 5 wt% of CsxWO3 nanoparticle solution spray-coated glass provides a 54.61% NIR shielding rate. Self-made CsxWO3 gives higher transmittance difference between the highest visible and lowest NIR range about 5~10% compared to that of the commercial CsxWO3 mixed with IPA at 2 wt.% and 5 wt.%.