Regular Article

Enhanced optical performance of thermochromic VO₂ based on multilayer designs

¹ School of Materials Science and Technology, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, P.R. China
² School of Architecture and Materials Engineering, Hubei University of Education, High-tech Second Road 129, Wuhan 430205, P.R. China

^* e-mail: guanchao.yin@whut.edu.cn

Received: 27 November 2019
Received in final form: 31 January 2020
Accepted: 5 February 2020
Published online: 3 March 2020

Abstract

VO₂ is a widely studied thermochromic material for smart windows. In this work, we comprehensively studied optical responses of VO₂-based multilayer structures. It is discovered that one-layer antireflection layer is capable of effectively enhancing both luminous transmittance (T_lum) and solar transmittance (T_sol), solar spectrum modulation (ΔT_sol) is however quite moderate. Employing a two-top-layer strategy further improves the optical performance of VO₂, especially with an increase of ΔT_sol from 0.068 to 0.082. Remarkably, combining a layer with an index of 2.2 at the VO₂/glass interface continues to enhance the optical performance, leading to the highest T_lum and ΔT_sol among the investigated multilayer structures. Compared to the base structure of VO₂/glass, it contributes to a relative enhancement of 26.4% (from 0.435 to 0.550) for T_lum (<τ_c), 35.3% (from 0.362 to 0.490) for T_lum (>τ_c), and 71.7% (from 0.060 to 0.103) for ΔT_sol.