Nanoporous thermochromic VO2 (M) thin films : controlled porosity, largely enhanced luminous transmittance and solar modulating ability
Law, Jia Yan
Loo, Say Chye Joachim
Date of Issue2014
School of Materials Science and Engineering
Vanadium dioxide is the most widely researched thermochromic material with a phase transition temperature (τc) of around 68 °C, and its thermochromic performance can be enhanced by adding nanoporosity. Freeze-drying has been employed to fabricate nanostructures with different porosities from 16 to 45% by varying the prefreezing temperature and precursor concentration. The luminous transmittance (Tlum) and solar modulating ability (ΔTsol) are greatly enhanced as a result of increasing pore size and pore density. The freeze-dried sample with 7.5 mL of H2O2 precursor dip-coated at 300 mm/min gives the best combination of thermochromic properties (Tlum ≈ 50%, ΔTsol = 14.7%), which surpasses the best combined thermochromic performance reported to date that we are aware of (Tlum ≈ 41%, ΔTsol = 14.1%).
© 2014 American Chemical Society.