The development of narrow-bandgap (Eg ~ 1.2 eV) mixed tin-lead (Sn-Pb) halide perovskites enables all-perovskite tandem solar cells. Whereas pure-lead halide perovskite solar cells (PSCs) have advanced simultaneously in efficiency and stability, achieving this crucial combination remains a challenge in Sn-Pb PSCs. Here Sn-Pb perovskite grains are anchored with ultra-thin layered perovskites to overcome the efficiency-stability tradeoff. Defect passivation is achieved both on the perovskite film surface and at grain boundaries, an approach implemented by directly introducing phenethylammonium ligands in the antisolvent. This improves device operational stability and also avoids the excess formation of layered perovskites that would otherwise hinder charge transport. Sn-Pb PSCs with fill factors of 79% and a certified PCE of 18.95% are reported - among the highest for Sn-Pb PSCs. Using this approach, a 200-fold enhancement in device operating lifetime is achieved relative to the non-passivated Sn-Pb PSCs under full AM1.5G illumination, and a 200-hour diurnal operating time without efficiency drop is achieved under filtered AM1.5G illumination.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-25
Acknowledged KAUST grant number(s): OSR-2017-CPF-3321-03
Acknowledgements: This work has been published (Adv. Mater. 2020, 32, 1907058). M. Wei and K. Xiao contributed equally to this work. This work is based in part on work supported by the US Office of Naval Research (Grant Award No.: N00014-17-1-2524), by an award (OSR-2017-CPF-3321-03) from the King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The work of H.T. is supported by National Key R&D Program of China (Grant No. 2018YFB1500102), the National Natural Science Foundation of China (Grant No. 61974063), the Jiangsu Provincial Natural Science Foundation (BK20190315) and the Thousand Talent Program for Young Outstanding Scientists in China. M.I.S. acknowledges the Government of Canada's Banting Postdoctoral Fellowship Program for financial support.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.