Directly hydrothermal growth of ultrathin MoS2 nanostructured films as high performance counter electrodes for dye-sensitised solar cells

Abstract

Ultrathin MoS₂ nanostructured films with a surface exposed layered nanosheet structure were successfully grown onto fluorine-doped tin oxide (FTO) conducting substrates by a facile one-pot hydrothermal method. After calcination at 400 °C in argon, the resulting MoS₂ films were directly used as counter electrodes (CEs) for dye-sensitised solar cells (DSSCs), exhibiting excellent DSSC performance. The hydrothermal reaction temperature and molar ratio of reaction precursors were found to have significant influence on the resulting structure of MoS₂, and thus the DSSCs performance. It was found that ultrathin MoS₂ nanostructured film with surface exposed layered nanosheet structures can be obtained by hydrothermal treatment of a reaction solution including (NH₄)₆Mo₇O₂₄·4H₂O and NH₂CSNH₂ with a molar ratio of 1 : 28 at 150 °C for 24 h. The obtained MoS₂ films as CEs for DSSCs showed the best light conversion efficiency of 7.41%, which was superior to Pt-based DSSCs (7.13%). The excellent DSSC performance could be due to high stability, good electrical conductivity, rich electrocatalytically active sites, and good electrolyte transport properties of the fabricated MoS₂ film with a surface layered nanosheet structure. This study demonstrated the applicability of a facile hydrothermal approach for direct growth of highly electrocatalytically active metal chalcogenide films as high performance CEs for DSSCs.