First-principles study on the phase transition temperature of X-doped (X = Li, Na or K) VO2

Vanadium dioxide (VO2) is one of the most interesting thermochromic materials with a phase transition temperature of 340 K. Our first-principles calculations indicate that Li, Na or K dopants with a doping level of 1 atomic percentage could reduce the phase transition temperature of VO2 by 43 K, 49 K, 94 K, respectively. In addition, the V-V chains feature the dimerization characteristics in the Li, Na or K doped VO2(R). The calculated electronic structures and optical properties indicate that K is an appropriate doping element for VO2, since it can effectively lower the phase transition temperature as well as enhance the near-infrared absorption.