High-Fill-Factor Perovskite Solar Cells via Pseudohalide Salt Modification of the Substrate to Mitigate Nonradiative Recombination at the Interface

Qili Song; Yiyi Li; Zhichao Lin; Xiangning Xu; Hongye Dong; Hairui Duan; Li Guan; Xiaowen Gao; Xi-Cheng Ai; Cheng Mu

doi:10.1021/acs.jpclett.3c02633

High-Fill-Factor Perovskite Solar Cells via Pseudohalide Salt Modification of the Substrate to Mitigate Nonradiative Recombination at the Interface

J Phys Chem Lett. 2023 Nov 9;14(44):9951-9959. doi: 10.1021/acs.jpclett.3c02633. Epub 2023 Oct 31.

Authors

Qili Song¹, Yiyi Li¹, Zhichao Lin¹, Xiangning Xu¹, Hongye Dong¹, Hairui Duan¹, Li Guan¹, Xiaowen Gao², Xi-Cheng Ai¹, Cheng Mu¹

Affiliations

¹ Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing 100872, P. R. China.
² Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China.

PMID: 37905503
DOI: 10.1021/acs.jpclett.3c02633

Abstract

The utilization of the sol-gel method for fabricating planar SnO₂ as the electron transport layer (ETL) induces numerous defects on the SnO₂ layer surface and perovskite film bottom, causing considerable deterioration of the device performance. Conventional inorganic salt-doped SnO₂ precursor solutions used for passivation may cause incomplete substrate coverage due to the presence of inorganic salt crystals, further degrading the device performance. Here, a substrate modification approach involving the pretreatment of a fluorine-doped SnO₂ (FTO) substrate with NH₄PF₆ is proposed. The interaction between PF₆^- ions and the FTO substrate enhances SnO₂ film quality; excess PF₆^- ions decrease the number of defects on the film surface. NH₄⁺ ions react with an -OH stabilizing agent in the SnO₂ solution and are eliminated during annealing. The combined effects suppress nonradiative recombination and ion migration at the ETL-perovskite interface. The corresponding high-quality perovskite solar cells (PSCs) exhibit a fill factor of ∼0.825; PSC efficiency increases from 19.59% to 22.32%.