Enhanced thermochromic properties and solar-heat shielding ability of W_xV_1-xO₂ thin films with Ag nanowires capping layers

Considerable efforts have been made to shift the phase transition temperature of metal-doped vanadium dioxide (VO₂) films nearer the ambient temperature while maintain the excellent thermochromic properties simultaneously. Here, we describe a facile and economic solution-based method to fabricateW-doped VO₂ (V_1-xW_xO₂) thn films with excellent thermochromic properties for the application of smart windows. The substitutional doping of tungsten atoms notably reduces the phase transition temperature to the ambient temperature and retains the excellent thermochromic property. Furthermore, Ag nanowires (NWs) are employed as capping layers to effectively decrease the thermal emissivity from 0.833 to 0.603, while the original near infrared region (NIR) modulation ability is not severely affected. Besides, the Ag NWs layers further depress the phase transition temperature as well as the hysteresis loop width, which is important to the fenestration application. These solution-grown Ag NWs/V_1-xW_xO₂ thin films exhibit excellent solar modulation ability, narrowed hysteresis loop width as well as low thermal emissivity, which provide a promising perspective into the practical application of VO₂-based smart windows.