Alternative buffer layers in Sb₂Se₃ thin‐film solar cells to reduce open‐circuit voltage offset

Antimony Selenide (Sb₂Se₃) thin-film solar cell configurations with alternative buffer layers are proposed to improve the efficiency by minimizing open‐circuit voltage offset (V_oc,offset). The conduction band offsets have been optimized not only at absorber/buffer (ΔE_C‐BA) but also at buffer/transparent conductive oxide (ΔE_C-TB). Voltage‐independent recombination rates in the quasi‐neutral region (R^b₀), the space‐charge region (R^d₀), and at the absorber/buffer interface (Rⁱ₀) of the Sb₂Se₃ solar cells with various configurations are individually modelled. The development of cell configurations causes to decrease the Rⁱ₀, R^d₀, and R^b₀, consequently reducing the V_oc,offset. It is found that the solar cell configuration of Mo/MoSe₂/Sb₂Se₃/TiO₂/ZnO_0.4S_0.6/Zn_0.93Mg_0.07O/ZnO:Al is suitable with the ΔE_C‐BA of 0.29 eV and ΔE_C‐TB of −0.2 eV, therefore considerably reducing V_oc,offset to approximately 0.52 V, and improving the efficiency to 15.46%.