Effect of lanthanum doping on modulating the thermochromic properties of VO2 thin films

Abstract

Lanthanum (La) doped vanadium dioxide (VO₂) thin films were fabricated through a facile sol–gel technique. The La doping was found to be effective for reducing the phase transition temperature (τ_c) of VO₂ below the 4 at% doping level, with a reducing rate of −1.1 °C per at%. In addition, below the 3 at% La doping level, the band gap (E_g) decreased steadily with the increasing addition of La dopants. 5 at% La doping can enhance both the integrated visible transmission (T_lum) and the solar modulating ability (ΔT_sol) simultaneously. The combination of T_lum = 50.1% and ΔT_sol = 10.3% represents the best values for VO₂ continuous thin films.