High Open Circuit Voltage in Sb₂S₃/Metal Oxide-Based Solar Cells

This paper presents for the first time Sb₂S₃-based solar cells operating on scaffold film. The scaffolds studied are Al₂O₃ and ZrO₂, for which no electron injection from the Sb₂S₃ to the Al₂O₃ or ZrO₂ is possible. As a result, one of the highest open circuit voltages (V_oc) of 0.712 V was observed for this solar cell configuration. Electron dispersive spectroscopy (EDS) was performed, revealing complete pore filling of the Sb₂S₃ into the metal oxide pores (e.g., Al₂O₃ or ZrO₂); the complete pore filling of the Sb₂S₃ is responsible for the photovoltaic performance (PV) of this unique solar cell structure. In addition, intensity modulated photovoltage and photocurrent spectroscopy (IMVS and IMPS) were performed to extract the electron diffusion length. Electron diffusion length in the range of 900 nm to 290 nm (depending on the light intensity) was observed, which further supports the operation of metal oxide/Sb₂S₃ solar cell configuration. Moreover, the Al₂O₃-based cells have longer electron diffusion length than the TiO₂-based cells, supporting the higher open circuit voltage of the noninjected metal oxide-based cells. This work demonstrates the potential of Sb₂S₃ to gain high voltage and to perform on a scaffold substrate without requiring electron injection.