Exploration of In₂S₃ as an Electron Transport Layer for All-Inorganic CsPbBr₃ Perovskite Solar Cells

In this paper, we demonstrate the fabrication of planar-based CsPbBr₃ perovskite solar cells with the use of In2 ~S3 as an electron transport layer (ETL) fabricated by chemical bath deposition. CsPbBr₃ films were fabricated by multi-step spin coating of PbBr₂ and CsBr ink, respectively, followed by annealing in air at 250 C for 30 min followed by deposition of a carbon-based electrode. The device showed an efficiency of 0.7 %(Js c=1.3 ~mA / cm2, ~Voc=1.165 ~V F FF=47 %.), which was higher than that of the device without an ETL with an efficiency of 0.4 %(Jsc=1.9 ~mA / cm2, ~Voc=0.685 ~V FF=. 32%). A relatively small grain sizes of the CsPbBr₃ film growth in the I n2 ~S3 layer (∼ 5 0 0 ~ n m) was thought to be responsible for the relatively low efficiency of the device compared to that of using a conventional TiO₂ layer as the ETL layer.