Expanding the Spectral Tunability of TiO₂ Nanocrystals by Codoping with Fluorine and Tungsten for Energy-Efficient Windows

Abstract

Exploitation of new solar blocking materials is crucial for low-carbon architectures. F–W codoped TiO2 with superior solar screening performance was prepared. The effects of codoping and reaction temperature on the composition and infrared screening performances of TiO2 nanoparticles were studied. Codoping with W and F produced spindle-shaped anatase TiO2 with a particle size of 7.7 nm. Tungsten substituted for titanium and fluorine substituted for oxygen in the lattices. XPS and EPR analyses verified the existence of abundant Ti3+ ions in the codoped TiO2. It was observed that the codoped TiO2 showed the strongest infrared blocking activity in comparison to the F-doped and undoped TiO2. The NIR screening efficiency of the coatings reaches 70.1% after codoping with 20% of tungsten and 30% of fluorine. Briefly, the enhanced NIR blockage activity of codoped TiO2 was the synergistic effect of F and W. The codoping of F and W increased the electron concentration in TiO2 and enhanced the NIR plasmonic absorption. Furthermore, the F–W codoped TiO2 films reduced the indoor temperature of the simulated house by 9.9 °C. Thus, the F–W codoped TiO2 films have potential applications in the field of energy-saving glazing.