Surface engineering on continuous VO₂ thin films to improve thermochromic properties: Top-down acid etching and bottom-up self-patterning

Surface engineering is an effective method to improve the thermochromic performance of VO₂. In this paper, an acid-etching top down method was proposed to tailor the VO₂ surface morphology from the continuous dense-packed surface to patterned structure, which exhibited the enhanced integrated visible transmittance (T_lum) and the enlarged solar modulating abilities (ΔT_sol). Moreover, a self-patterning approach was also illustrated to improve the thermochromic properties. The proposed surface engineering methods represent a facile and cost-effective approach for enhancing thermochromic properties that could promote the application of VO₂ thin films in smart windows.