Effects of working pressure on the material and defect properties of Sb₂S₃ thin-film solar cells achieved by the VTD method

Antimony sulfide (Sb₂S₃), an emerging material for photovoltaic devices, has drawn growing research interest due to its inexpensive and high-throughput device production. In this study, the material and defect properties of Sb₂S₃ thin films prepared by the vapor transport deposition (VTD) method at different working pressures were studied. Solar cells based on a structure of glass/ITO/CdS/Sb₂S₃/Au were fabricated. The working pressure showed a significant effect on the device’s performance. The current density versus voltage measurement and scanning electron microscopy analysis outcome were utilized to investigate the photovoltaic and microstructural properties in the samples. The compositional analysis by energy dispersive X-ray spectroscopy measurement confirmed the Sb/S ratio as 2:2.8 for the thin films. The identification and characterization of the defects present in Sb₂S₃ thin films were performed via admittance measurements. Compared to the defect density, the defect energy level was found to inherit a more important role in the device’s performance. The best solar cell performance with better crystal quality, lower defect density, and longer capture lifetime was achieved under the substrate working pressure of 2 Pa. The highest efficiency was found to be 0.86% with V_oc = 0.55 V, J_sc = 5.07