Xinyi Shen, Wing Tung Hui, Shuaifeng Hu, Fengning Yang, Junke Wang, Jin Yao, Atse Louwen, Bryan Siu Ting Tam, Lirong Rong, David P. McMeekin, Kilian B. Lohmann, Qimu Yuan, Matthew C. Naylor, Manuel Kober‐Czerny, Seongrok Seo, Philippe Holzhey, Karl‐Augustin Zaininger, M. Greyson Christoforo, Perrine Carroy, Vincent Barth, Fion Sze Yan Yeung, Nakita K. Noel, Michael Johnston, Yen‐Hung Lin, Henry J. Snaith
Abstract Vacuum-based deposition is a scalable, solvent-free industrial method ideal for uniform coatings on complex substrates. However, all-vacuum-deposited perovskite solar cells fabricated by thermal evaporation trail solution-processed counterparts in efficiency and stability due to film quality challenges, necessitating advancement and improved understanding. Here, we report a co-evaporation route for 1.67-eV wide-bandgap perovskites by introducing a PbCl 2 co-source to optimize film quality. We promote perovskite formation with pronounced (100) ‘face-up’ orientation and deliver a certified all-vacuum-deposited solar cell with 18.35% efficiency (19.3% in the laboratory) for 0.25-cm 2 devices (18.5% for 1-cm 2 cells). These cells retain 80% of peak efficiency after 1,080 h under the ISOS-L-2 protocol. Leveraging operando hyperspectral imaging, we provide spatiotemporal spectral insight into halide segregation and trap-mediated recombination, correlating microscopic luminescence features with macroscopic device performance while distinguishing radiative from non-ideal recombination channels. We further demonstrate 27.2%-efficient 1-cm 2 evaporated perovskite-on-silicon tandem cells and outdoor stability of all-vacuum-deposited tandems in Italy, retaining ~80% initial performance after eight months.