Facile Solution Process of VO₂ Film with Mesh Morphology for Enhanced Thermochromic Performance

The fabrication and applications of VO₂ film continue to be of considerable interest due to their good thermochromic performance for smart windows. However, low visible transmittance (T_lum) and solar modulation efficiency (∆T_sol) impede the application of VO₂ film, and they are difficult to improve simultaneously. Here, a facile zinc solution process was employed to control the surface structure of dense VO₂ film and the processed VO₂ film showed enhanced visible transmittance and solar modulation efficiency, which were increased by 7.5% and 9.5%, respectively, compared with unprocessed VO₂ film. This process facilitated the growth of layered basic zinc acetate (LBZA) nanosheets to form mesh morphology on the surface of VO₂ film, where LBZA nanosheets enhance the visible transmittance as an anti-reflection film. The mesh morphology also strengthened the solar modulation efficiency with small caves between nanosheets by multiplying the times of reflection. By increasing the zinc concentration from 0.05 mol/L to 0.20 mol/L, there were more LBZA nanosheets on the surface of the VO₂ film, leading to an increase in the solar/near-infrared modulation efficiency. Therefore, this work revealed the relationship between the solution process, surface structure, and optical properties, and thus can provide a new method to prepare VO₂ composite film with desirable performance for applications in smart windows.