Beschreibung:
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 CH3NH3PbI3: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 TiO2. Furthermore, clear correlation between the LUMO of the fullerene material and the open circuit voltage of the solar cells is found.