Interfacial modification strategy by lead chloride post-treatment enables 8.05% efficient Sb2S3 solar cells
image: PbCl2 post-treatment to Sb2S3/HTL interface could passivate interface defects and reduce non-radiative recombination of Sb2S3 solar cell. Specifically, Cl can passivate the defect of VS and SbS, and Pb enabled effective p-type doping at the Sb2S3 interface with the help of VS removal. And the synergistic effect of Pb and Cl elements matched well with HTL energy level, facilitated hole extraction and enhanced the interface conductivity. The optimal power conversion efficiency of above device reaches 8.05%.
Credit: Nano research, Tsinghua University Press
Antimony chalcogenides (Sb2X3, X = S, Se) have garnered significant attention in recent years, particularly Sb2S3, which is considered as one of the ideal top-cell materials for tandem solar cells. It is due to its high absorption coefficient, environmental friendliness, stability, and suitable bandgap of approximately 1.7 eV. Despite these advantages, the highest reported certified power conversion efficiency of Sb2S3 solar cells remains at 8.08%, much room below its theoretical efficiency limit of 28.64%. Recent research efforts have predominantly focused on enhancing the quality of the Sb2S3 absorber layer. However, the interface between the Sb2S3 absorber and the transport layer also plays a critical role in device performance.
Herein, the research team from Huazhong University of Science and Technology (HSUT) proposed a strategy to modify the back interface of Sb2S3 through PbCl2 post-treatment. Systematic characterization revealed that the hole transfer rate was significantly enhanced and charge recombination was markedly suppressed. These improvements were attributed to the diffusion of Cl ions into the Sb2S3 lattice, where they filled sulfur vacancies (VS) and inhibited the formation of antisite defects (SbS). Furthermore, the combined effect of Pb and Cl incorporation facilitated p-type doping at the Sb2S3 back interface, which increased conductivity and improved energy level alignment. The synergistic effect of defect passivation and energy level alignment resulted in a significant increase in the fill factor (FF) to 66.02% and achieved a champion PCE of 8.05%. This study highlights the critical role of the Sb2S3/HTL interface in device performance and provides valuable insights for future research in this area.
The HUST team published their article in Nano research on September 25, 2025.
This work was supported by the National Natural Science Foundation of China (Grant No. 62374065), the Interdisciplinary Research Promotion of HUST (No. 2023JCYJ040), Project for Building a Science and Technology Innovation Center Facing South Asia and Southeast Asia (202403AP140015) and the Innovation Project of Optics Valley Laboratory (No. OVL2024BB017). The authors thank Testing Center of HUST and the Center for Nanoscale Characterization & Devices (CNCD), WNLO-HUST for facility access.
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Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.