Transparent Anti-Icing Moiré-Film Enhancing Photovoltaic Stability in Extreme Cold Climates

Accelerated degradation and power loss of solar cells in cold climates remain major challenges to renewable energy deployment. The photothermal film offers a promising solution by converting sunlight into heat to remove ice and snow from solar panels. However, enhancing photothermal performance often entails reduced visible (VIS) light transmittance of films, thereby compromising solar cell efficiency. Tailoring optical designs to balance the optimal light absorption between the device and the film is essential for photovoltaic anti-icing/snow. Herein, we present outdoor data from grid-connected photovoltaic modules, revealing a 58% electricity loss caused by ice/snow shading effects. To address this, we developed transparent photothermal films featuring a moiré light-trapping structure, achieving high VIS transmittance (∼93.0%) and enhanced near-infrared absorption (∼65.8%). We confirmed that the meter-scale photothermal film ensures that operational modules remain ice-free in −20 °C outdoor conditions, and the ice-melting phase diagram indicates its effective anti-icing range down to −30 °C under AM 1.5G, one-sun illumination. Day-night cycling tests on perovskite cells demonstrated sustained anti-icing performance, yielding a 7.5-fold increase in daily power output during winter conditions. The film's long-term stability and robust de-icing performance under weak-light scenarios demonstrate the its feasibility for extreme cold applications.