VO₂-Based Thermochromic Films Modified by Transparent Matter-Repellent Surfaces with Superior Self-Cleaning Ability...

Vanadium dioxide (VO₂)-based thermochromic films are highly attractive for smart window applications due to their ability to dynamically modulate solar radiation in response to ambient temperature. However, their practical deployment is significantly hindered by poor long-term stability in outdoor environments, vulnerability to surface contamination, and insufficient mechanical durability. Herein, we propose a novel strategy to obtain self-cleaning and durable VO₂ composite films, consisting of a VO₂ thermochromic layer covered by either a SiO₂ or TiO₂ overcoat and further modified by a transparent and matter-repellent surface. Multifunctional VO₂ composite films are rationally designed to exhibit superior repellence towards various liquids, thereby imparting excellent anti-fouling property. Crucially, the VO₂ composite film is engineered for high optical transparency to ensure it does not compromise the solar modulation ability of the underlying VO₂ layer. Furthermore, the robust mechanical properties of the SiO₂ or TiO₂ overcoat with matter-repellent modification provide effective protection against abrasion and scratch damages. The resulting VO₂-based composite films demonstrate significantly enhanced environmental stability and operational reliability while maintaining desirable thermochromic performance. This work presents a promising strategy to overcome the stability and durability challenges facing VO₂ smart windows, paving the way for their real-world application in energy-efficient buildings.