Improving Photocurrent in Sb₂Se₃ Thin‐Film Solar Cells Through Sb₂S₃ Electron Reflector Layer: A Simulation Study

Abstract

In this paper, antimony sulfide (Sb2S3) material is utilized as an electron reflector layer (ERL) in antimony selenide (Sb2Se3) solar cells. The primary objective of this simulation study is to mitigate recombination at the back contact and improve cell performance. It is demonstrated that incorporating Sb2S3 ERL into a traditional Sb2Se3 cell yields enhancements in both the short‐circuit current density (Jsc) and carrier collection rate. This enhancement is assigned to the reduced interface recombination rate at the back electrical contact. The strong electric field at the p+‐Sb2S3/p‐Sb2Se3 electrical contact creates a barrier with a height of 0.34 eV in the conduction band that hinders the electron carriers' access to the back contact. This barrier effectively improves cell efficiency. The use of this method has demonstrated a significant improvement in the external quantum efficiency (EQE) at longer wavelengths, specifically ranging from ≈800 to 1100 nm. Using this method, the Sb2Se3 active layer thickness is reduced to 1 µm, which reduces the fabrication cost. After optimizing the device, the cell efficiency enhances from 9.2% to 13.1%, resulting in a significant improvement compared to traditional Sb2Se3 solar cells without an ERL, thanks to the incorporation of a suitable Sb2S3 ERL.