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Internal homojunction Sb2Se3 solar cell

Nature Photonics (2026)Cite this article

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Abstract

Antimony selenide (Sb2Se3) has emerged as a promising thin-film photovoltaic absorber due to its ideal bandgap (1.1–1.3 eV), high absorption coefficient (>105 cm−1) and environmentally benign composition. However, Sb2Se3 solar cells (SSCs) often suffer from large open-circuit voltage losses owing to the weak built-in fields and severe non-radiative recombination at the interfaces and within the absorber layer. Here we demonstrate a composition-driven strategy for controlling carrier polarity that we used to form an n-type/p-type homojunction within the Sb2Se3 absorber layer. By precisely tuning the chemical potentials of Se and Sb, we are able to manipulate the conductivity type and achieve carrier densities exceeding 1014 cm−3 for the n- and p-type states. With this materials design, we demonstrate that incorporating the p–n homojunction into a planar SSC simultaneously enhances the built-in electric field and passivates deep-level defects. These synergistic effects promote carrier separation, reduce non-radiative recombination and accelerate carrier extraction. As a result, the internal-homojunction-enhanced SSC delivers a power conversion efficiency of 10.15% for thermally evaporated Sb2Se3 devices and an ultralow open-circuit voltage deficit of 0.459 V. This study proposes a proof-of-concept device structure for SSCs that opens a new pathway for improving device efficiency.

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Fig. 1: n-type to p-type conductivity transition in Sb2Se3 films.
Fig. 2: Carrier-polarity formation mechanism.
Fig. 3: Depth-resolved evidence of a built-in homojunction in an Sb2Se3 absorber.
Fig. 4: Device structure and PV performance of SSCs.
Fig. 5: Internal-homojunction-driven carrier generation, transport and recombination.
Fig. 6: Bulk non-radiative recombination by deep-level defects.

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Data availability

All data supporting the findings of this study are available within the paper and its Supplementary Information. Other data that support the findings of this study are available from the corresponding authors upon request. Source data are provided with this paper.

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant Nos. 22275180, 52572274, T.C.), the Fundamental Research Funds for the Central Universities (Grant No. WK2490000002, T.C.), Major Science and Technology Projects of Anhui Province (Grant No. AHZDCYCX-LSDT2023-10, T.C.) and the University Synergy Innovation Program of Anhui Province (Grant No. GXXT-2023-031, R.T.). We thank BL10B (https://cstr.cn/31131.02.HLS.PES) at the National Synchrotron Radiation Laboratory.

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Authors and Affiliations

  1. Department of Materials Science and Engineering, School of Chemistry and Materials Science, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China

    Junjie Yang, Jianyu Li, Shuwei Sheng, Zhiyuan Cai, Zichen Ruan, Bo Che, Rongfeng Tang & Tao Chen

  2. Institute of Optoelectronic Materials and Devices, School of Materials Science and Engineering, Jiangxi University of Science and Technology, Ganzhou, P. R. China

    Ke Li

  3. School of Microelectronics, Hefei University of Technology, Hefei, P. R. China

    Rongfeng Tang

  4. Institute of Deep Space Sciences, Deep Space Exploration Laboratory, Hefei, P. R. China

    Tao Chen

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Contributions

T.C. supervised the research. J.Y., J.L. and S.S. contributed equally to this work. J.Y. and T.C. conceived the original concept and designed the experiments. J.Y., J.L. and S.S. fabricated the devices and conducted the PV and optical characterization and analysis. J.L. did the TA spectroscopy measurements and performed the SEM and TEM analyses. K.L., Z.R. and B.C. were involved in materials characterization and device simulation. Z.C. conducted the DFT calculations. J.Y., R.T. and T.C. co-wrote the paper. T.C., R.T., S.S. and J.Y. revised the paper, and all authors commented on the paper.

Corresponding authors

Correspondence to Rongfeng Tang or Tao Chen.

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The authors declare no competing interests.

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Nature Photonics thanks Yaohua Mai, Ding-Jiang Xue and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–25, Tables 1–16 and Notes 1–7.

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Yang, J., Li, J., Sheng, S. et al. Internal homojunction Sb2Se3 solar cell. Nat. Photon. (2026). https://doi.org/10.1038/s41566-026-01888-1

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