Hydrogen-doping induced reduction in the phase transition temperature of VO2: a first-principles study

Abstract

VO₂ is a promising thermochromic material that can intelligently control the transmittance of sunlight in the near-infrared region in response to temperature change, although the high phase transition temperature (T_c) of 340 K restricts its wide application. Our first-principles calculations show that hydrogen is an efficient dopant which can stabilize the metallic VO₂ phase at ambient temperature through reducing T_c by 38 K/at% H. The reduction in T_c is coupled with the changes in atomic and electronic structures, i.e., the V–V chains feature the dimerization characteristics in H-doped VO₂(R) and the V–O bonds become less ionic due to the formation of a typical H–O covalent bond. In addition, hydrogen-doped VO₂ is more sensitive to external strain as compared with pure VO₂, implying that T_c can be further regulated through a combination of H-doping and strain.