Efficient SnO2/CdS double electron transport layer for Sb2S3 film solar cell

Highlights: • We developed a simple chemical solution process method to synthesize SnO₂ colloidal and fabricated SnO₂ ETL. • SnO₂/CdS double ETL was prepared by combining SnO₂ and CdS. • The PCE of Sb₂S₃ solar cell is 5.3% based on the SnO₂/CdS double ETL • The SnO₂ ETL enhanced the surface smoothness and passivated the defects of Sb₂S₃ films. -- Abstract: Sb₂S₃ has been proven to be a very promising light absorbing material for photovoltaic applications due to its low cost, high stability, non-toxicity, and abundant elemental storage. Electron transport layer (ETL) is a very crucial factor to the performances of Sb₂S₃ solar cells. Here we developed a simple chemical solution process method to synthesize SnO₂ colloidal and fabricated SnO₂ ETL at low-temperature first, and then SnO₂/CdS double ETL was prepared by combining SnO₂ and CdS. The power conversion efficiency of Sb₂S₃ solar cell is 5.3% based on the SnO₂/CdS double ETL, whereas the device based on CdS ETL only exhibites a PCE of 4.3%. Experimental analyses revealed that the introduction of SnO₂ ETL enhanced the grain size of Sb₂S₃ films and passivated interfacial defects thus enhancing device efficiency. Our results show the potential application of SnO₂ in the planar Sb₂S₃ solar cell.