Modeling the impact of grain size on device characteristics of Sb2Se3 solar cells

Abstract

In this paper, we developed an analytical model to study the impact of grain size and the associated electrical parameters on the device characteristics and spectral response of Sb2Se3 antimony solar cells. Current-voltage characteristics as well as internal and external quantum efficiencies of the cell were modelled and the impact of grain size, effective intra-grain diffusion length, surface recombination velocity at grain boundaries, and carrier lifetime have been investigated. The profile of Electric field at the grain boundaries, the impact of grain size on the performance parameters of the cell have been investigated and the intra-grain diffusion length as an effective parameter on device performance parameters has been studied. The results indicate that a larger grain size is essential for surpassing recombination loss and improving the open-circuit voltage while a better carrier collection and spectral response can improve the short-circuit current density. A practical outcome of our study confirms the necessity of post-deposition surface passivation of Sb2Se3 absorber layers to surpass the recombination loss at grain boundaries and develop larger grains from an optimized deposition process to enhance the carrier collection for a more efficient and stable Sb2Se3 solar cell.