Abstract
Antimony selenide (Sb2Se3) has an optimal bandgap and absorption coefficient for thin film solar cell applications and comprises earth abundant elements. The rate of increase in reported power conversion efficiencies has slowed due to a persistently large open circuit voltage deficit attributed to detrimental concentrations of point defects. Here we use depth-profiling positron annihilation lifetime spectroscopy to study Sb2Se3 crystals and thin films. The method is specific to neutral and negative charge states of vacancy-related defects. Both monovacancy and divacancy defects are identified in intrinsic and n-type samples but no monovacancy defects are detected in the p-type sample. Comparison of the experimental positron lifetimes with density functional theory calculated values provide evidence for the observation of Sb monovacancies in the –3 state and of Se monovacancies in the –2 state. The results are consistent with recent density function theory predictions that the Sb and the Se monovacancy defects both have accessible negative charge states.
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The positron lifetime data that support the findings of this study and source data for display items have been deposited in figshare with the identifier 10.6084/m9.figshare.c.8192384. The processed data used in this study is provided within the paper and the Supplementary Information file.
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Acknowledgements
D.J.K. gratefully acknowledges the financial support provided by FRM-II to perform the high-intensity positron beam measurements at Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany. J.W. acknowledges funding from the “Area of Advance - Materials Science” at Chalmers University of Technology and the Swedish Research Council (2019-03993). The computations were partly performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at NSC and PDC. J.M. and K.D. would like to acknowledge support from EPSRC grants EP/N014057/1m and EP/M024768/1. M.D. and W.E. gratefully acknowledges BMBF-grants 05K13WN1-POSIANALYSE, 05K16WN1-POSITEC and 05K19WN1-POSILIFE of the German Federal Office of Research and Education.
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D.J.K. with K.D., J.M., and T.D.C.H. designed the study. K.D. and T.D.C.H. supplied samples. D.J.K., M.D. and W.E. performed the positron annihilation experiments. D.J.K. and M.R.M.E. fitted the experimental spectra. J.W. and E.B. performed the DFT and TC-PAW-DFT calculations. D.J.K., with help from J.W., T.D.C.H. and K.D., wrote the main draft. All authors commented on the manuscript.
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Keeble, D.J., Hobson, T.D.C., Wiktor, J. et al. Detection and identification of vacancy defects in antimony selenide. Nat Commun (2026). https://doi.org/10.1038/s41467-025-68153-x
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DOI: https://doi.org/10.1038/s41467-025-68153-x
