Nanostructured vanadium dioxide films
Date of Issue2015
School of Materials Science and Engineering
Vanadium (IV) oxide (VO2) is the most widely researched thermochromic (TC) material. Owing to its fully reversible metal-insulator transition (MIT) at the critical temperature (τc) of 68 ˚C, which is the closest to the room temperature and adjustable through doping, it has the potential application as the energy-saving coating for smart windows. Recent researches revealed that introducing porosity and fabrication of nanoparticles (NPs)/matrix composite foils could produce VO2 coatings at the best TC performance. This research employs lyophilisation (freeze drying) technique to fabricate nanoporous VO2 thin films and agglomeration-free NPs. The best combination of TC properties for the former achieved Tlum ≈ 50% and ΔTsol = 14.7%, while that for the latter achieved average Tlum = 35%, ΔTsol = 6.8%, τc = 64.5 ˚C and Δτc = 4.5 ˚C, with small particle size and narrow distribution (37-53 nm) as well as high crystallinity (LC = 36.76 J/g, close to the commercial VO2 powder).