The influence of different electron transport layers on the hydrothermal Sb2S3 quasi-epitaxial growth

Abstract

Sb₂S₃ has attracted much attention due to its high absorption coefficient, abundant elemental reserves and stable chemical properties. However, key issues such as interface recombination and poor energy level matching have restricted the improvement of device performance. This study investigated the effects of three electron transport layers (ETLs), CdS, TiO₂ and SnO₂, on the hydrothermal quasi-epitaxial growth of Sb₂S₃. CdS could induce the formation of a continuous and dense Sb₂S₃ film through S-Sb chemical bridge bonds, while TiO₂ and SnO₂, due to their surface inertness, led to island-like growth of Sb₂S₃, accompanied by interface holes and defects. Device test results indicated that the device with CdS as the ETL had the best performance: power conversion efficiency (PCE) of 6.11 %, the lowest saturation current density (J₀), and effective suppression of interface recombination. Devices with TiO₂ and SnO₂ as ETLs exhibited lower open-circuit voltage (V_oc) and short-circuit current density (J_sc), and poor device performance (2.82 % and 1.09 %) due to severe interface recombination. SCAPS-1D simulation further confirmed that CdS had significant advantages in energy level matching and interface defect control, making it the most suitable ETL among the three for the quasi-epitaxial growth of Sb₂S₃, providing a key reference for the development of high-efficiency Sb₂S₃ solar cells.