Enhancing NIR Shielding Properties of Au/CsWO3 Composite via Physical Mixing and Solvothermal Processes

This research aims to enhance the near-infrared (NIR) shielding ability of cesium tungsten bronze (CsWO₃) by increasing the spectral absorption in this region through the incorporation of gold nanorods (Au_NR). Two approaches were used to prepare the composite materials: physical mixing and solvothermal process. The effects of gold nanorods content on the crystalline size, particle size, shape, and optical properties of the composite were investigated systematically using DLS, TEM, XRD, and UV–Vis spectroscopy techniques, respectively. The physical mixing process synergizes Au_NR and CsWO₃ into a composite which has better NIR absorption than that of neat Au_NR and CsWO₃ nanorods. A composite with 10 mol% of Au_NR shows the highest NIR absorption ability due to the surface plasmon resonance and energy coupling between Au and CsWO₃. With the solvothermal process, the CsWO₃ nanorods grow up to 4–7 microns when the Au_NR content increases to 0.8 mol% due to the incorporation of the Au atoms. The microsized CsWO₃ rods have superior NIR shielding property compared to other conditions, including the Au_NR+CsWO₃ nanocomposite with 10 mol% of Au_NR from the physical mixing process.