Evaluation of Cd _{1– <i>x</i>} Zn <i> _x </i> S as electron transport layer in superstrate and inverted configurations of Sb ₂ Se ₃ solar cells with n-i-p structure

Abstract

Abstract In this work, we evaluate the role of the ternary compound, Cd 1– x Zn x S, as an electron-transport layer (ETL) in the n-i-p structure of antimony selenide (Sb 2 Se 3 ) solar cells. The incorporation of Zn reduces the amount of Cd and contributes to improving the power-conversion efficiency of the solar cell. On the other hand, the n-i-p structure makes it possible to overcome two issues that impair the efficiency of Sb 2 Se 3 solar cells: the potential barrier due to the rear contact and the low hole concentration in the Sb 2 Se 3 absorber material. In this paper, we present a theoretical work on Sb 2 Se 3 solar cells using the SCAPS 1-D software. The theoretical analysis allows us to understand the impact of the semiconductor parameters on efficiency and also to find the optimal values for an optimized device. The optimal molar composition of the ternary compound is investigated in the superstrate and inverted configurations. Parameters such as the thickness, defect density, and the acceptor concentration of the Cd 1– x Zn x S and Sb 2 Se 3 layers are optimized. Also, we analyze the impact of interface-defect density at the hole-transport layer (HTL) (Sb 2 Se 3 ) and the ETL (Sb 2 Se 3 ). Following optimization, a power-conversion efficiency ( η ) of 14.29% is obtained using Cd 0.4 Zn 0.6 S as the ETL and Cu 2 O as the HTL in the superstrate configuration. This simulation process is expected to guide other experimentalists in the design and manufacture of solar cells.