Title：Carbon Nanotubes and Graphene for Flexible Perovskite Solar Cells

Invited Speaker: Prof. Shigeo Maruyama

     Department of Mechanical Engineering, The University of Tokyo

Energy NanoEngineering Laboratory, 

     National Institute of Advanced Industrial Science and Technology

Venue: Chemistry Building,A717 

Time: 4:00 pm,Dec.4,2017 

Abstract：

Single-walled carbon nanotubes (SWNTs), graphene, and fullerenes (C60 and PCBM) can be efficiently used in lead halide Perovskite solar cells. A film of SWNTs or graphene may act as not only a flexible and stretchable transparent-conductive layer but also a carrier-selective layer, i.e., electron-blocking layer or hole-blocking layer. Based on our experiences of using nanotube films in CNT-Si solar cells and organic polymer solar cells, 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 and the application in flexible devices on polyethylene terephthalate (PET). The devices with nanocarbon-based electron-blocking-layer and metal electrode showed comparable PCE as the conventional design with organic electron-blocking layer and top metal electrode. The normal-type perovskite solar cell, composed of ITO/C60/CH3NH3PbI3/SWNTs, can achieve a PCE of 17% with spiro-MeOTAD as dopant to SWNTs. This structure with a perovskite layer sandwiched by C60 and SWNTs can lead to the solar cells without hysteresis and with much improved air-stability. The effective passivation of perovskite materials to prevent from moisture can be achieved with C60 and SWNTs. More recent configuration is using SWNT films as both anode and cathode electrodes. The new physical understanding of the band alignment is discussed.