Sb₂S₃ Seed-Mediated Growth of\nLow-Defect Sb₂S₃ on a TiO₂ Substrate\nfor Efficient Solar Cells

Abstract

Hydrothermal\ndeposition was recently developed to prepare an antimony\nselenosulfide thin film with large grain size and flat and compact\nsurface morphology, leading to efficient breakthrough in solar cell\napplications. However, the deposition of antimony chalcogenide is\nalways based on the CdS substrate. The narrow band gap of CdS generates\nparasitic absorption that causes light harvesting loss in the solar\ndevice. TiO₂ with a wide band gap allows more efficient\nlight harvesting, while its deposition on high-quality antimony chalcogenide\nfilms has not been realized. Here, we demonstrate that the Sb₂S₃ seed layer introduced on the TiO₂ surface can initiate the deposition of Sb₂S₃. The Sb₂S₃ seed layer provides crystal nuclei\nfor the hydrothermal growth of a highly dense and compact Sb₂S₃ film on the TiO₂ substrate. This kind of\nSb₂S₃ film exhibits reduced defect density and\nimproved charge-carrier transport compared with that deposited on\na bare TiO₂ surface, finally leading to an efficiency improvement\nof 32%. This method provides an effective strategy for depositing\nSb₂S₃ on wide band gap oxide substrates in the\nhydrothermal deposition system for optoelectronic device applications.