(Invited) Thermochromic Phase Transitions in VO2-Based Thin Films for Energy-Saving Applications

Abstract

The thermochromic transition in vanadium dioxide (VO2) has potential application as a smart energy-saving window coating, but the temperature of the transition must be depressed from 68 °C to Earth ambient temperatures by the incorporation of transition metal impurities. In this paper, we describe a high throughput combinatorial experiment to characterize the V1-xMxO2 phase space, in which M is another metal, for thermochromic transitions. Thin film combinatorial libraries were prepared by pulsed laser deposition on hot silicon substrates, and the M impurities were found to substitute into the VO2 crystalline lattice on the V-site. For M = Ta, Nb, and W, the thermochromic transition temperature was depressed with increasing M concentration. Doping with multiple M atoms is also easily accomplished by combinatorial synthesis and was found to have unexpected effects on the thermochromic transition.