Heterojunction formed via 3D-to-2D perovskite conversion for photostable wide-bandgap perovskite solar cells

Jin Wen; Yicheng Zhao; Pu Wu; Yuxuan Liu; Xuntian Zheng; Renxing Lin; Sushu Wan; Ke Li; Haowen Luo; Yuxi Tian; Ludong Li; Hairen Tan

doi:10.1038/s41467-023-43016-5

Heterojunction formed via 3D-to-2D perovskite conversion for photostable wide-bandgap perovskite solar cells

Nat Commun. 2023 Nov 6;14(1):7118. doi: 10.1038/s41467-023-43016-5.

Authors

Jin Wen¹, Yicheng Zhao², Pu Wu¹, Yuxuan Liu¹, Xuntian Zheng¹, Renxing Lin¹, Sushu Wan³, Ke Li³, Haowen Luo¹, Yuxi Tian³, Ludong Li¹, Hairen Tan⁴

Affiliations

¹ National Laboratory of Solid State Microstructures, Frontiers Science Center for Critical Earth Material Cycling, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210023, China.
² State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China.
³ School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
⁴ National Laboratory of Solid State Microstructures, Frontiers Science Center for Critical Earth Material Cycling, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210023, China. hairentan@nju.edu.cn.

Abstract

Light-induced halide segregation constrains the photovoltaic performance and stability of wide-bandgap perovskite solar cells and tandem cells. The implementation of an intermixed two-dimensional/three-dimensional heterostructure via solution post-treatment is a typical strategy to improve the efficiency and stability of perovskite solar cells. However, owing to the composition-dependent sensitivity of surface reconstruction, the conventional solution post-treatment is suboptimal for methylammonium-free and cesium/bromide-enriched wide-bandgap PSCs. To address this, we develop a generic three-dimensional to two-dimensional perovskite conversion approach to realize a preferential growth of wider dimensionality (n ≥ 2) atop wide-bandgap perovskite layers (1.78 eV). This technique involves depositing a well-defined MAPbI₃ thin layer through a vapor-assisted two-step process, followed by its conversion into a two-dimensional structure. Such a two-dimensional/three-dimensional heterostructure enables suppressed light-induced halide segregation, reduced non-radiative interfacial recombination, and facilitated charge extraction. The wide-bandgap perovskite solar cells demonstrate a champion power conversion efficiency of 19.6% and an open-circuit voltage of 1.32 V. By integrating with the thermal-stable FAPb_0.5Sn_0.5I₃ narrow-bandgap perovskites, our all-perovskite tandem solar cells exhibit a stabilized PCE of 28.1% and retain 90% of the initial performance after 855 hours of continuous 1-sun illumination.