Morphology-Controlled Multi-Layer Construction for Efficient and Durable Electrochromic Properties of Amorphous WO3 Films

Abstract

The electrochromic device represents an emerging technology to conserve energy and mitigate greenhouse gas concentrations. Higher electrochromic performance and durability are imperative to achieve its widespread application. However, electrochromic devices frequently encounter issues such as cracking and feeling of the surface during extended cycles of ion intercalation/deintercalation. Hence, this study proposes a morphology-controlled multi-layer structure for achieving a crack-free surface with stable performance. The fabricated multi-layer films consisted of smaller particles in the bottom layer and larger particles in the top layer, resulting in a crack-free surface. The combination of increased electrolyte accessibility in the top layer and reduced diffusion length in the bottom layer contributed to swift and efficient electrochromic performance. Furthermore, a crack-free surface with reduced residual stress and controlled grain boundary improved cycle stability. Our findings present innovative models for metal oxide-based electrochromic materials and offer valuable insights for designing multi-layer structures.