Coordination Compound Guided a Novel Composite Film with Zn 2 V 2 O 7 Nanoflake and VO 2 @Zn 2 V 2 O 7 Nanoparticle for Enhanced Thermochromism Smart Window.

Thermochromic vanadium dioxide (VO 2 ) 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 VO 2 . In this study, a novel approach is employed utilizing a coordination compound to finely tune the growth of a VO 2 based composite film, yielding a hierarchical film comprising Zn 2 V 2 O 7 nanoflakes and VO 2 @Zn 2 V 2 O 7 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 VO 2 nanoparticles. In addition, the Zn 2 V 2 O 7 -VO 2 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.