Room-Temperature Synthesis of Inorganic–Organic Hybrid Coated VO₂ Nanoparticles for Enhanced Durability and Flexible Temperature-Responsive Near-Infrared Modulator Application

Vanadium dioxide is one kind of desirable infrared modulator for sensors because of its remarkable temperature-responsive infrared modulation ability via autogeneic metal–insulator transition. However, the detriments of poor chemical stability and narrow scope of extensive-researched application (e.g., smart windows) restrict its mass production. Here, we propose a VO2@MgF2@PDA inorganic–organic hybrid coated architecture for greatly enhancing the optical durability more than 13 times in contrast to pristine VO2 and the transmittance difference between room and high temperature changed within 20% (decreasing from 25 to 20.1%) at λ = 1200 nm after the ageing time of 1000 h at constant temperature (60 °C) and relative humidity (90%). Furthermore, based on the as-synthesized durability-enhanced nanoparticles, we fabricated a flexible sensor for temperature-field fluorescence imaging by integrating the VO2-based near-infrared modulator with the upconversion fluorescence material. Additionally, the formation mechanism of VO2@MgF2 core–shell nanoparticles was studied in detail. The inorganic–organic combination strategy paves a new way for improving the stability of nanoparticles, and the use of VO2-based flexible temperature-fluorescence sensors is a promising technique for remote and swift temperature-field distribution imaging on complicated and campulitropal surfaces.