Challenges in fabricating all-perovskite tandem solar cells as modules rather than as single-junction configurations include growing high-quality wide-bandgap perovskites and mitigating irreversible degradation caused by halide and metal interdiffusion at the interconnecting contacts. We demonstrate efficient all-perovskite tandem solar modules using scalable fabrication techniques. By systematically tuning the cesium ratio of a methylammonium-free 1.8–electron volt mixed-halide perovskite, we improve the homogeneity of crystallization for blade-coated films over large areas. An electrically conductive conformal “diffusion barrier” is introduced between interconnecting subcells to improve the power conversion efficiency (PCE) and stability of all-perovskite tandem solar modules. Our tandem modules achieve a certified PCE of 21.7% with an aperture area of 20 square centimeters and retain 75% of their initial efficiency after 500 hours of continuous operation under simulated 1-sun illumination.

We propose an innovative solar photothemal battery technology to develop all-solid-state lithium–air batteries operating at ultra-low temperatures where a plasmonic air electrode can efficently harvest solar energy and convert it into heat, enabling efficient charge storage and transmission in electrolyte/electrode materials. Such batteries demonstrate a high discharge capacity (∼3600 mA h g⁻¹) at −73 °C and record-cycle life both at −73 °C and room temperature.