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

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.