N,S co-doping of VO2 films with enhancing luminous transmittance and investigation of phase transition

Vanadium dioxide (VO₂), known for its phase transition properties, is a promising candidate for thermochromic applications. However, its high phase transition temperature and low visible light transmittance restrict its applicability. To overcome these challenges, we propose a co-doping strategy in this study. Using a simple annealing technique, we synthesize N,S co-doped VO₂ films that exhibit phase transition at ambient temperature. Optical evaluations reveal a substantial improvement, with a 24.3 % increase in luminous transmittance for the co-doped films compared to undoped VO₂ films. Furthermore, we conducted first-principles calculations to investigate the effects of S and N dopants on the electronic structure of VO₂, offering valuable insights into how these dopants influence the phase transition process. These results offer an alternative approach to enhance the optical properties of VO₂ and contribute to a deeper understanding of its phase transition mechanisms.