Tuning the Crystallization and Photothermal Aging Chemistry of CsPb0.4Sn0.6I3 for Inorganic Perovskite Tandem Photovoltaics

Chenghao Duan; Mingyu Hu; Qiliang Zhu; Shiang Li; Ning Liu; Zheng Zhang; Liming Ding; Jianhang Qiu; Lin Guo; Xinhui Lu; Shihe Yang; Keyou Yan

doi:10.1002/anie.202507761

Tuning the Crystallization and Photothermal Aging Chemistry of CsPb_0.4Sn_0.6I₃ for Inorganic Perovskite Tandem Photovoltaics

Angew Chem Int Ed Engl. 2025 May 9:e202507761. doi: 10.1002/anie.202507761. Online ahead of print.

Authors

Chenghao Duan^{1

2}, Mingyu Hu³, Qiliang Zhu¹, Shiang Li⁴, Ning Liu¹, Zheng Zhang¹, Liming Ding⁵, Jianhang Qiu⁶, Lin Guo⁷, Xinhui Lu⁴, Shihe Yang³, Keyou Yan¹

Affiliations

¹ School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, Guangdong Basic Research Center of Excellence for Energy and Information Polymer Materials, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, China, 510000.
² School of Energy Science and Technology, Henan University, Zhengzhou, China, 450000.
³ School of Advanced Materials, Shenzhen Graduate School, Peking University, Shenzhen, China, 518055.
⁴ Department of Physics, The Chinese University of Hong Kong, Hong Kong, China, 999077.
⁵ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, China, 510006.
⁶ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China, 110016.
⁷ School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China, 100191.

PMID: 40346716
DOI: 10.1002/anie.202507761

Abstract

The poor performance of inorganic narrow bandgap perovskite solar cells (PSCs) hinders the development of inorganic perovskite tandem solar cells (IPTSCs). We modulate the crystallization and photothermal aging chemistry for CsPb_0.4Sn_0.6I₃ (1.31 eV) with guanidinoacetic acid (GCA) to develop IPTSC. The CsPb_0.4Sn_0.6I₃:GCA PSC reaches an efficiency of 16.93% and maintains an initial efficiency of ∼80% (T₈₀) for 1300 h under maximum power point tracking (MPPT) at 65 °C. We identify that there are not only ionic migration species (I^-, I₃ ^-) but also molecular migration species (SnI₄, I₂) for CsPb_0.4Sn_0.6I₃ correlated to the photothermal dynamics. For CsPb_0.4Sn_0.6I₃ film, the intractable pinholes accelerate the iodine migration to the electrode and photothermal degradation. The photodegradation of PbI₂ produces I₂ and then promotes the Sn²⁺ oxidation to Sn⁴⁺, causing tin migration in the form of SnI₄ to accumulate at the electron transport layer/perovskite interface, and in turn generating more pinholes and Sn-Pb segregation. In CsPb_0.4Sn_0.6I₃:GCA film, due to the coordination bonds with Pb/Sn cations and hydrogen bonds with I^- ions, GCA incorporation-induced pinhole-free morphology can significantly suppress ion/molecule migration. Combined with CsPbI₂Br subcell, two-terminal IPTSC delivers an efficiency of 22.18%, accompanied by T₈₀ = 850 h under MPPT at 65 °C.

Keywords: Crystallization regulation; Inorganic Sn‐Pb perovskite; Ion/molecule migration; Photothermal aging; Tandem solar cells.

Abstract

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