中国物理B ›› 2026, Vol. 35 ›› Issue (2): 28801-028801.doi: 10.1088/1674-1056/ae156b

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Band engineering and recombination mechanisms in lead-free perovskite solar cells

Wei Liu(刘维)1, Tingxue Zhou(周庭雪)1, Liang Chu(楚亮)2,†, and Xing'ao Li(李兴鳌)1,‡   

  1. 1 New Energy Technology Engineering Laboratory of Jiangsu Province & Institute of Advanced Materials & School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;
    2 Institute of Carbon Neutrality and New Energy & School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
  • 收稿日期:2025-08-20 修回日期:2025-09-30 接受日期:2025-10-21 发布日期:2026-01-31
  • 通讯作者: Liang Chu, Xing'ao Li E-mail:chuliang@hdu.edu.cn;lxahbmy@126.com
  • 基金资助:
    This project was supported by the National Natural Science Foundation of China (Grant Nos. 52102165 and 62474056) and the Natural Science Foundation of Nanjing University of Posts and Telecommunications (Grant Nos. NY221029 and NY222165).

Band engineering and recombination mechanisms in lead-free perovskite solar cells

Wei Liu(刘维)1, Tingxue Zhou(周庭雪)1, Liang Chu(楚亮)2,†, and Xing'ao Li(李兴鳌)1,‡   

  1. 1 New Energy Technology Engineering Laboratory of Jiangsu Province & Institute of Advanced Materials & School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China;
    2 Institute of Carbon Neutrality and New Energy & School of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
  • Received:2025-08-20 Revised:2025-09-30 Accepted:2025-10-21 Published:2026-01-31
  • Contact: Liang Chu, Xing'ao Li E-mail:chuliang@hdu.edu.cn;lxahbmy@126.com
  • Supported by:
    This project was supported by the National Natural Science Foundation of China (Grant Nos. 52102165 and 62474056) and the Natural Science Foundation of Nanjing University of Posts and Telecommunications (Grant Nos. NY221029 and NY222165).

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摘要： All-inorganic lead-free perovskite solar cells have emerged as environmentally benign candidates; however, their device performance is still constrained by pronounced carrier recombination losses in the bulk and at interfaces. By combining energy band alignment analysis with detailed modeling of recombination mechanisms, a systematic strategy for optimizing hole transport layers is developed. The results reveal that a negative valence band offset produces a cliff-like interface, which facilitates hole extraction while also accounting for the observed variations in open-circuit voltage. Furthermore, short-circuit current losses are quantitatively attributed to different recombination pathways, modeled by incorporating radiative, Shockley-Read-Hall, Auger, and interface recombination processes. This comprehensive approach not only clarifies the correlation between energy level alignment and recombination dynamics but also highlights the competing roles of band offset and interface defects in determining device performance. The optimized device architecture, based on Ge-based lead-free perovskites, achieves a power conversion efficiency of 25.1 %, with an open-circuit voltage of 1.29 V, a short-circuit current density of 22.5 mA$\cdot $cm$^{-2}$, and a fill factor of 86.3 %. These findings provide theoretical guidance for designing stable, high-performance, and environmentally friendly lead-free perovskite solar cells.

关键词: perovskite solar cells, lead-free, band engineering, recombination

Abstract: All-inorganic lead-free perovskite solar cells have emerged as environmentally benign candidates; however, their device performance is still constrained by pronounced carrier recombination losses in the bulk and at interfaces. By combining energy band alignment analysis with detailed modeling of recombination mechanisms, a systematic strategy for optimizing hole transport layers is developed. The results reveal that a negative valence band offset produces a cliff-like interface, which facilitates hole extraction while also accounting for the observed variations in open-circuit voltage. Furthermore, short-circuit current losses are quantitatively attributed to different recombination pathways, modeled by incorporating radiative, Shockley-Read-Hall, Auger, and interface recombination processes. This comprehensive approach not only clarifies the correlation between energy level alignment and recombination dynamics but also highlights the competing roles of band offset and interface defects in determining device performance. The optimized device architecture, based on Ge-based lead-free perovskites, achieves a power conversion efficiency of 25.1 %, with an open-circuit voltage of 1.29 V, a short-circuit current density of 22.5 mA$\cdot $cm$^{-2}$, and a fill factor of 86.3 %. These findings provide theoretical guidance for designing stable, high-performance, and environmentally friendly lead-free perovskite solar cells.

Key words: perovskite solar cells, lead-free, band engineering, recombination

中图分类号:  (Solar cells (photovoltaics))

  • 88.40.H-
88.40.hj (Efficiency and performance of solar cells)