Carbon Nanotubes and Graphene for Perovskite Solar Cells
Single-walled carbon nanotubes (SWNT), graphene, and fullerene (C60 and PCBM) would be very efficiently used in lead halide Perovskite solar cells. A film of SWNTs or graphene can be flexible and stretchable transparent-conductive layer. At the same time, this film can be carrier-selective layers, i.e., electron-blocking-layers or hole-blocking-layers. Based on our experiences of using nanotube films for CNT-Si solar cells  and organic polymer solar cells [2,3], we have explored the application of SWNT films for organic-inorganic perovskite solar cells. We have demonstrated the replacement of ITO in inverted-type perovskite solar cells,SWNTs/PEDOT:PSS/CH3NH3PbI3/PCBM/Al . The flexible application on polyethylene terephthalate (PET) is also demonstrated . With the improved perovskite structure, a film of carbon nanotubes or graphene can be practical replacement of ITO for the flexible transparent electrode of inverted perovskite solar cells . This work was supported by JSPS KAKENHI Grant Numbers JP25107002 and JP15H05760.