Wen Jin, Zhao Yicheng, Wu Pu, Liu Yuxuan, Zheng Xuntian, Lin Renxing, Wan Sushu, Li Ke, Luo Haowen, Tian Yuxi, Li Ludong, Tan Hairen
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.
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.
Nat Commun. 2023 Nov 6;14(1):7118. doi: 10.1038/s41467-023-43016-5.
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 MAPbI 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 FAPbSnI 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.
光诱导卤化物偏析限制了宽带隙钙钛矿太阳能电池和串联电池的光伏性能及稳定性。通过溶液后处理实现二维/三维混合异质结构是提高钙钛矿太阳能电池效率和稳定性的典型策略。然而，由于表面重构对成分的敏感性，传统的溶液后处理对于无甲铵且富含铯/溴的宽带隙钙钛矿太阳能电池并非最优选择。为解决这一问题，我们开发了一种通用的三维到二维钙钛矿转换方法，以在宽带隙钙钛矿层（1.78电子伏特）上实现更高维度（n≥2）的优先生长。该技术包括通过气相辅助两步法沉积一层定义明确的MAPbI薄层，然后将其转换为二维结构。这种二维/三维异质结构能够抑制光诱导卤化物偏析，减少非辐射界面复合，并促进电荷提取。宽带隙钙钛矿太阳能电池的最高功率转换效率为19.6%，开路电压为1.32伏。通过与热稳定的FAPbSnI窄带隙钙钛矿集成，我们的全钙钛矿串联太阳能电池的稳定功率转换效率为28.1%，在连续1太阳光照855小时后仍保留90%的初始性能。
