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Vacuum deposition methods are increasingly applied to the preparation of perovskite films and devices, in view of the possibility to prepare multilayer structures at low temperatures. Vacuum-deposited, wide-bandgap solar cells based on mixed cation and mixed anion perovskites have been scarcely reported, due to the challenges associated with the multiple-sources processing of perovskite thin-films. In this work, we describe a 4-sources vacuum deposition process to prepare wide-bandgap perovskites of the type FA1-nCsnPb(I1-xBrx)3 with tunable bandgap and controlled morphology, using FAI, CsI, PbI2 and PbBr2 as the precursors. The simultaneous sublimation of PbI2 and PbBr2 allows to decouple and control the relative Br/Cs content, resulting in homogeneous perovskite films with bandgap in the 1.7 eV-1.8 eV range and no detectable halide segregation. Solar cells based on 1.75 eV bandgap perovskites show efficiency up to 16.8% and promising stability, maintaining 90% of the initial efficiency after 2 weeks of operation.
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Gil Escrig, Lidón Dreessen, Chris Palazón Huet, Francisco Hawash, Zafer Moons, Ellen Albrecht, Steve Sessolo, Michele Bolink, Henk 2021 Efficient Wide-Bandgap Mixed-Cation and Mixed-Halide Perovskite Solar Cells by Vacuum Deposition Acs Energy Letters 6 2 827 836 |