Sequential vacuum-evaporated perovskite solar cells with more than 24% efficiency

Vacuum evaporation is promising for the high-throughput fabrication of perovskite solar cells (PSCs) because of its solvent-free characteristic, precise control of film thickness, and compatibility with large-scale production. Nevertheless, the power conversion efficiency (PCE) of PSCs fabricated by vacuum evaporation lags behind that of solution-processed PSCs. Here, we report a Cl-containing alloy-mediated sequential vacuum evaporation approach to fabricate perovskite films. The presence of CI in the alloy facilitates organic ammonium halide diffusion and the subsequent perovskite conversion reaction, leading to homogeneous pinhole-free perovskite films with few defects. The resulting PSCs yield a PCE of 24.42%, 23.44% (certified 22.6%), and 19.87% for 0.1, 1.0, and 14.4 square centimeters (mini-module, aperture area), respectively. The unencapsulated PSCs show good stability with negligible decline in performance after storage in dry air for more than 4000 hours. Our method provides a reproducible approach for scalable fabrication of large-area, high-efficiency PSCs and other perovskite-based optoelectronics.

Automated summary

Vacuum evaporation is a promising method for the fabrication of perovskite solar cells, with the advantages of precise film thickness control and compatibility with large-scale production. A Cl-containing alloy-mediated sequential vacuum evaporation approach was developed to fabricate perovskite films with high uniformity and few defects, resulting in high power conversion efficiency. The method provides a reproducible approach for scalable fabrication of large-area, high-efficiency perovskite solar cells and other perovskite-based optoelectronics.