Thermal evaporated C60 modified by Pt as counter electrode for dye-sensitized solar cells

Abstract Almost all carbon-based materials as counter electrode (CE) for dye-sensitized solar cells (DSSCs) with good performance have been identified in previous studies. Unfortunately, the device with fullerene (C60) or its derivative on fluorine doped tin oxide (FTO) substrate prepared by spin-coating was not the case. Our experimental results show that the C60 fabricated by vacuum thermal deposition performs much better than that prepared by spin-coating though the fill factor (FF) and power conversion efficiency (PCE) are still poor. Further improvement has been achieved in this study by trace Pt modifying thermal deposited C60 CE with a device efficiency of 5.78%, comparable to the one with standard Pt CE. This composite CE was obtained by thermal decomposing a small amount of chloroplatinic acid hexahydrate on FTO prior to C60. The trace Pt underneath the C60 film is believed to improve the conductivity of the C60 CE and then the performance of DSSCs.