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Vol. 19 (2027)

A Buried Sulfonate Molecular Bridge for Synchronous Charge Transport and Defect Passivation in High-Performance Perovskite Solar Cells

https://doi.org/10.1007/s40820-026-02278-6
Leying Zha
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China
Weilu Ding
Center of Ionic Liquids and Green Energy, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
Yalin Gao
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China
Xiao Wu
Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong 999077, People’s Republic of China
Tinglu Song
Experimental Center of Advanced Materials School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
Changhua Li
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China
Chenghao Duan
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China
Xinhui Lu
Department of Physics, The Chinese University of Hong Kong, New Territories, Hong Kong 999077, People’s Republic of China
Guilong Cai
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China
Suojiang Zhang
Longzihu New Energy Laboratory, Zhengzhou Institute of Emerging Industrial Technology, School of Energy Science and Technology, Henan University, Zhengzhou 450000, People’s Republic of China

Corresponding Author: Suojiang Zhang

sjzhang@ipe.ac.cn

Nano-Micro Letters, Vol. 19 (2027), Article Number: 35

Abstract

The quality of the buried interface between the self-assembled molecules (SAM) and the perovskite layer directly governs the processes of charge carrier transport and non-radiative recombination, which ultimately dictates the efficiency and stability of the inverted perovskite solar cells. However, the simultaneous mitigation of poor SAM layer adhesion and perovskite substrate interface defects remains a significant challenge. Herein, low-cost and readily available 2‑formylbenzenesulfonic acid sodium salt (2‑FAS) is employed as a bifunctional interlayer to molecularly bridge the SAM and perovskite. The benzene ring of 2‑FAS interacts via π–π stacking with the SAM, strengthening adhesion and promoting hole transfer, while its sulfonate group (-SO3−) coordinates with Pb2+ to regulate crystallization and passivate surface defects. As a result, the 2-FAS-modified devices deliver a champion power conversion efficiency of 26.21%, with a significant fill factor of 86.15%. Furthermore, Na+ from 2‑FAS occupies A‑site vacancies in the perovskite lattice, which effectively suppresses ion migration and phase transition, thereby enhancing structural integrity. Benefiting from these combined effects, unencapsulated devices retain over 90% of their initial PCE after 4500 h of storage in a nitrogen atmosphere, demonstrating exceptional long-term stability.


Highlights:
1 Bridging the 2-formylbenzenesulfonic acid salt molecule at the self-assembled molecules/perovskite buried interface enhances charge transfer via π–π stacking and passivates defects via Pb2+ coordination, yielding a superior power conversion efficiency of 26.21%.
2 The modified devices demonstrate exceptional storage stability, retaining over 90% of their initial power conversion efficiencies after 4500 h in a nitrogen atmosphere without encapsulation.
3 Na+ from 2-formylbenzenesulfonic acid salt effectively occupy A-site vacancies in the perovskite lattice, reinforcing structural stability and substantially improving device longevity.

Keywords

Buried interface Sodium sulfonate salt Carrier transport Defect passivation Perovskite solar cells
Zha, Leying, Weilu Ding, Yalin Gao, Xiao Wu, Tinglu Song, Changhua Li, Chenghao Duan, Xinhui Lu, Guilong Cai, and Suojiang Zhang. 2026. “A Buried Sulfonate Molecular Bridge for Synchronous Charge Transport and Defect Passivation in High-Performance Perovskite Solar Cells”. Nano-Micro Letters 19 (August):35. https://doi.org/10.1007/s40820-026-02278-6.
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