Sb₂(S_1-xSe_x)₃ solar cells: The impact of radiative and non-radiative loss mechanisms

The compound Sb₂(S_1-xSe_x)₃ has recently attracted a great deal of attention from the scientific community for solar cell applications. However, Sb₂(S_1-xSe_x)₃ inorganic solar cell efficiencies are still limited to values lower than 7%, further studies contributing to a better understanding of the limiting factors behind this technology being necessary. In particular, no theoretical works on Sb₂(S_1-xSe_x)₃ solar cell modeling have been previously reported. In this work, we present results on Sb₂(S_1-xSe_x)₃ solar cell modeling under the radiative and non-radiative limits for the first time, where our results are compared to experimental reported data. First, the impact of different Se/(S + Se) compositional ratios and absorber thicknesses on Sb₂(S_1-xSe_x)₃ solar cell parameters under the radiative limit is studied, demonstrating that an efficiency of 29% can be achieved under Se/(S + Se) compositional ratios in the range of 0.34-0.48 for Sb₂(S_1-xSe_x)₃ thicknesses higher than 1.5 μm. Furthermore, the impact of different linearly graded band-gaps and a notch-shape configuration of grading are evaluated. In addition, the role of different Sb₂(S_1-xSe_x)₃ minority carrier lifetime values on solar cells is estimated, demonstrating that for absorbers described by minority carrier lifetime values about 10^-9 s, it would be better to fabricate Sb₂(S_1-xSe_x)₃ solar cells with Se/(S + Se) compositional ratios lower than 0.4. Finally, the influence of low illumination intensity values is presented and discussed.