Acta Phys. -Chim. Sin.

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Obscuring effect of current mismatch on ion migration in allperovskite tandem solar cells

Dapeng Geng1,2, Fan Li1,2, Zhaosheng Xia1,2, Gang Wang2, Feihong Ye1, Zhiliang Chen1, Jian Mao3, Xuanhua Li4, Xingang Ren1,2, Zhixiang Huang1,2   

  1. 1 State Key Laboratory of Opto-Electronic Information Acquisition and Protection Technology, Anhui University, Hefei 230601, Anhui Province, China;
    2 Key Laboratory of Intelligent Computing & Signal Processing, Anhui University, Hefei 230601, Anhui Province, China;
    3 State Key Laboratory of Photovoltaic Science and Technology, College of Future Information Technology, Institute of Optoelectronics, Fudan University, Shanghai 200438, China;
    4 State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, Shaanxi Province, China
  • Received:2025-12-22 Revised:2026-01-29 Accepted:2026-03-03
  • Contact: Xingang Ren, Zhixiang Huang, Xuanhua Li, Zhiliang Chen, Jian Mao E-mail:xgren@ahu.edu.cn;zxhuang@ahu.edu.cn;lixh32@nwpu.edu.cn;zhiliang.chen@ahu.edu.cn;maojian@fudan.edu.cn

Abstract: The intrinsic ionic characteristics of metal halide hybrid perovskite materials represent a critical factor limiting the long-term operational stability and reliability of perovskite solar cells. Compared with traditional photovoltaic materials, perovskite features a soft crystal lattice with weak ionic bonding, which enables the migration of mobile ions. Due to the slow response characteristics of mobile ions and the electric field shielding effect, PSCs exhibit hysteresis in current density–voltage measurements. This phenomenon not only reduces the accuracy of efficiency evaluation, but also leads to unstable output during practical operation and even affects the long-term stability of the devices, thereby posing a significant obstacle to the commercialization of perovskite photovoltaic technology. In two-terminal perovskite tandem solar cells, the operating mechanism is more complex. Their series structure requires current matching between the two subcells. Current mismatch causes each subcell to contribute differently to the overall performance, thereby introducing additional complexity to the analysis of ion migration, charge accumulation, and hysteresis behavior. In this study, by constructing a comprehensive opto-electro-ionic model, the ionic dynamics and hysteresis characteristics of all-perovskite TSCs under different current matching conditions were systematically analyzed. The results show that when the subcells are currentmatched, the hysteresis effect is dominated by the subcell with higher ion density; when the subcells are current-mismatched, the hysteresis effect is dominated by the “current-limiting” subcell with smaller shortcircuit current density, while the ionic behavior in the other subcell is “obscured”, and shows no contribution to the overall hysteresis. Additionally, the impact of interface defects at the perovskite/hole transport layer on the hysteresis is greater than that at the perovskite/electron transport layer in inverted-structure perovskite TSCs. Therefore, implementing precise interface passivation and ion suppression strategies for the “currentlimiting” subcell is the optimal approach to reduce device hysteresis and enhance performance. The results in this work offer a guideline to optimize two subcells and multiple interfaces, dramatically reducing both experimental costs and trial-and-error efforts. By enabling more targeted and economical refinement, the study accelerates the path toward industrial production of stable, high-efficiency all-perovskite tandem solar cells.

Key words: All-perovskite tandem solar cells, Hysteresis effect, Current mismatch, Ion dynamics