Efficiency bottleneck in antimony chalcogenide solar cells Xinwei Wang 1 , Seán R. Kavanagh 1,2 , Alex M. Ganose 3 , Zhenzhu Li 1 and Aron Walsh 1 1 Department of Materials, Imperial College London, UK, 2 Thomas Young Centre and Department of Chemistry, University College London, UK, 3 Department of Chemistry, Imperial College London, UK Antimony chalcogenides (Sb 2 X 3 , X=S, Se) have attracted tremendous interest as earth-abundant and environmental-friendly alternatives among thin-film photovoltaic light absorbers due to their promising electronic and optical properties [1,2] . However, the current record conversion efficiency (~ 10%) [3] is far from optimal and the origin of the underlying bottleneck remains controversial. Possible causes that degrade the device performance reported in previous literature include: i) improper orientation of Sb 2 X 3 films [4] ; ii) self-trapped carriers [5,6] and iii) defect-assisted recombination [7] . In this talk, I will present our most recent work investigating the three possible reasons shown above that affect the conversion efficiency in Sb 2 X 3 based on first-principles calculations. I will first introduce the anisotropy in bulk Sb 2 X 3 structures and the resulting impacts on structural, electronic and optical properties [8] . Then I will present charge carrier transport properties in Sb 2 X 3 and show that the performance of Sb 2 X 3 solar cells is unlikely to be limited by intrinsic self-trapping [9] . Finally, I will introduce the influence of point defects in Sb 2 X 3 on the conversion efficiency and identify the potentially detrimental defects. Theoretically upper-limit conversion efficiencies based on thickness-dependent optical absorption and intrinsic point defects will also be discussed. References 1. Chen C, Li W, Zhou Y, et al. Applied Physics Letters , 2015, 107(4): 043905. 2. Lei H, Chen J, Tan Z, et al. Solar Rrl , 2019, 3(6): 1900026. 3. Zhao Y, Wang S, Li C, et al. Energy & Environmental Science , 2022, 15(12): 5118-5128.
4. Zhou Y, Wang L, Chen S, et al. Nature Photonics , 2015, 9(6): 409-415. 5. Yang Z, Wang X, Chen Y, et al. Nature communications , 2019, 10(1): 1-8. 6. Tao W, Zhu L, Li K, et al. Advanced Science , 2022, 9(25): 2202154. 7. Dong J, Liu Y, Wang Z, et al. Nano Select , 2021, 2(10): 1818-1848. 8. Wang X, Li Z, Kavanagh S R, et al. Physical Chemistry Chemical Physics , 2022, 24(12): 7195-7202. 9. Wang X, Ganose A M, Kavanagh S R, et al. ACS Energy Letters , 2022, 7(9): 2954-2960.
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© The Author(s), 2021
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