(Invited) Efficient Electron Transport Layer-Free Solar Cells Based on Innovative Perovskite:Fullerene Blends

A variety of novel fullerene materials, showing different electron accepting capabilities, has been synthesized and used to prepare electron transport layer-free solar cells based on CH 3 NH 3 PbI 3 :fullerene blends. The photovoltaic study performed over a series of devices verifies the suitability of this electron transport layer-free strategy as a promising alternative to build efficient solar cells avoiding the use of TiO 2 . Furthermore, clear correlation between the LUMO of the fullerene material and the open circuit voltage of the solar cells is found.