Minimized optical scattering of MXene-derived 2D V2O5 nanosheet-based electrochromic device with high multicolor contrast and accuracy

Abstract

An electrochromic device (ECD) based on the redoxation of the transition metal oxide (TMO) is a key technology for obtaining a stable and efficient color display. Developing the TMO-based electrochromic layer in a complex nanotexture can effectively acquire additional surface redox sites for improved ECD performance, while the increased roughness compensates the color range and accuracy through the excessive scattering effect. In this paper, we report the fabrication of a two-dimensional (2D) V2O5 nanosheet through the oxidation of single-layer V2CTx MXene. Benefitting from the high aspect-ratio morphology, the 2D V2O5 nanosheet-based electrochromic layer was fabricated in the optimized nanotexture with significantly reduced number of scattering sites such as surface roughness and internal voids, while acquiring large ion capacitance. The 2D V2O5 nanosheet-based ECD exhibited vibrant multicolor transformation with excellent optical contrast (53.98 %), response time (6.5 s for coloration and 5.0 s for bleaching) and coloration efficiency (91.1 cm2 C-1), which were far more superior to those obtained from a commercial V2O5 powder. In our study, we provide a new perspective based on optical engineering for designing electrochromic materials with the desired color variations.