Investigating the Impact of Intrinsic Defects on Cu₂SiSe₃ for PV Applications

<br/>Metal chalcogenides have seen renewed interest in recent years with the hope that they will deliver stable, non-toxic thin-film solar cells with efficiencies that can match silicon and halide perovskite-based devices.^[1] To this end we have begun an initial investigation into the electronic and optical properties of Cu₂SiSe₃, and it has shown initial promise as a photovoltaic absorber with a calculated band gap of ~1.52 eV and a maximum efficiency of 30% for a 1.5 mm film. <br/> <br/>However, a promising band gap and absorption coefficient is not sufficient to determine if a new material will achieve high efficiencies in devices. Non-radiative recombination processes, driven by defect states in the band gap, can drastically reduce carrier lifetimes, and thus performance.^[2]Therefore, in this project we investigate all potential intrinsic defects in Cu2SiSe3 to determine how they may affect carrier lifetimes and thus device performance.^[3]<br/> <br/>[1] Hadke, S.; Huang, M.; Chen, C.; Tay, Y. F.; Chen, S.; Tang, J.; Wong, L., Chem. Rev., 2021. <br/>[2] Huang, Y.-T.; Kavanagh, S. R.; Scanlon, D. O.; Walsh, A.; Hoye, R. L. Z. Nanotechnology, 2021, 32 (13), 132004. <br/>[3] Nicolson, A. T. J.; Kavanagh, S. R.; Watson, G. W.; Palgrave, R. G.; Scanlon, D. O. Submitted (2022)