Coordination Compound Guided a Novel Composite Film with Zn₂V₂O₇ Nanoflake and VO₂@Zn₂V₂O₇ Nanoparticle for Enhanced Thermochromism Smart Window

Thermochromic vanadium dioxide (VO₂) can intelligently modulate the transmittance of indoor solar radiation to reduce the energy consumption of air conditioning in buildings. Nevertheless, it remains a great challenge to simultaneously improve the luminous transmittance (T_lum) and solar modulation ability (ΔT_sol) of VO₂. In this study, a novel approach is employed utilizing a coordination compound to finely tune the growth of a VO₂ based composite film, yielding a hierarchical film comprising Zn₂V₂O₇ nanoflakes and VO₂@Zn₂V₂O₇ core-shell nanoparticles. Remarkably, the resulting composite films showcase exceptional optical performance, achieving a T_lum of up to 73.0% and ΔT_sol of 15.7%. These outcomes are attributed to the antireflection properties inherent in the nanoflake structure and the localized surface plasmon resonance of well-dispersed VO₂ nanoparticles. In addition, the Zn₂V₂O₇-VO₂ film demonstrates remarkable environmental durability, retaining 90% of its initial ΔT_sol even after undergoing aging at 100 °C under 50% relative humidity for a substantial period of 30 days - a durability equivalent to ≈20 years under ambient conditions. This work not only achieves a harmonious balance between T_lum and ΔT_sol but also introduces a promising avenue for the design of distinctive composite nanostructures.