Smart Window Structures Based on Highly Conductive, Transparent Metal Nanomeshes and Thermochromic Perovskite Films

Abstract Smart windows are energy‐efficient windows whose optical transparency can be switched between highly transparent and opaque states in response to incident solar illumination. Transparent and conductive metal nanomesh (NM) films are promising candidates for thermochromic smart windows due to their excellent thermal conductivity, high optical transparency at near infrared wavelengths, and outstanding stability. In this study, ZnO/Au/Al 2 O 3 NM films with periodicities of 200 and 370 nm are reported. The ZnO/Au/Al 2 O 3 NM film with a 370 nm periodicity exhibits a transmittance over 90% at 550 nm and sheet resistance lower than 20 Ω sq −1 . Based on a standard figure of merit, this structure outperforms current state‐of‐the‐art NM films. Here, the integration of ZnO/Au/Al 2 O 3 NM films into a thermochromic perovskite smart window is also demonstrated. The transparency of the smart window structure is manipulated by transient resistive heating to trigger the thermochromic transition to the opaque state, which can be then maintained solely by 1‐sun, AM 1.5 G illumination. This climate‐adaptive, low power‐activated, and fast‐switching smart window structure opens new pathways toward its practical application in the real world.