Dion–Jacobson-Phase 2D Sn-Based Perovskite Comprising a High Dipole Moment of π-Conjugated Short-Chain Organic Spacers for High-Performance Solar Cell Applications
Jie Qian, Yawen Li, Yifan Shen, Xiangqing Zhao, Chong Wu, Hao Gu, Zhipeng Zhang, Yanfeng Chen, Bo Cai, Junmin Xia, Wei Shen, Kun Cao, Lihui Liu, Lijun Zhang, Gang Cheng, Shufen Chen, Guichuan Xing, Wei Huang
Abstract
The stability issue of Sn-based perovskite solar cells (PSCs) is expected to be resolved by involving a two-dimensional (2D) layered structure. However, Sn-based 2D PSCs, especially Dion–Jacobson (DJ)-phase ones with potentially good stability, have rarely been reported. Herein, superior DJ-phase Sn 2D perovskites with 3-aminobenzylamine (3ABA 2+ ) or 4-aminobenzylamine (4ABA 2+ ) π-conjugated short-chain ligands are reported to fabricate efficient 2D lead-free PSCs. Notably, the high dipole moment of the 3ABAI 2 organic spacer is approved to possess faster charge transfer for forming (3ABA)FA 4 Sn 5 I 16 2D perovskite with an extremely low exciton binding energy (only 84 meV). In combination with a diacetate partial substitution and methylamine iodide/bromide (MAI/MABr) post-treatment strategy to delay crystallization and improve compactness and coverage of the perovskite film, a record power conversion efficiency (PCE) of 6.81% and stability of 840 h (less than 5% degradation in a N 2 atmosphere for unencapsulated devices) are acquired in eventual (3ABA)FA 4 Sn 5 I 16 2D PSCs, which are among the highest PCE and the longest stability of Sn-based 2D PSCs reported to date. Our work provides a prospective molecule design and film preparation strategy of 2D Sn perovskites toward nontoxic high-performance tin-based PSCs, which pushes the almost stagnant research forward.