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

Sb 2 S 3 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, TiO 2 and SnO 2 , on the hydrothermal quasi-epitaxial growth of Sb 2 S 3 . CdS could induce the formation of a continuous and dense Sb 2 S 3 film through S-Sb chemical bridge bonds, while TiO 2 and SnO 2 , due to their surface inertness, led to island-like growth of Sb 2 S 3 , 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 ( J 0 ), and effective suppression of interface recombination. Devices with TiO 2 and SnO 2 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 Sb 2 S 3 , providing a key reference for the development of high-efficiency Sb 2 S 3 solar cells.