Rapid thermal annealing assisted facile solution method for tungsten-doped vanadium dioxide thin films on glass substrate

Vanadium dioxide VO2 is an important thermochromic material with useful applications in smart energy devices. This paper describes the synthesis of high-quality vanadium dioxide thermochromic thin films directly on glass substrate without any barrier layer prepared using a simple solution method. We demonstrate that 50 nm thick VO2 films display excellent visible transmittance (76.9% on glass, 69.4% on fused silica) and a large NIR switching efficiency (33.8% on glass, 44.3% on fused silica) at 1600 nm. It is found that the metal to semiconductor phase transition temperature T-c of undoped films can be reduced from a theoretical value of 68 degrees C to 49.4 degrees C by rapid thermal annealing. WithWdoping a continuous drop in the T-c is observed and for VO2 with 2% W doping, a T-c of 25.8 degrees C is achieved. These good optical properties and the near room-temperature phase transition temperature suggest that solution processing with the rapid thermal annealing process is a feasible method to obtain this promising material on glass substrate for practical application in thermochromic smart windows. (c) 2020 Elsevier B.V. All rights reserved.