Perylene diimides: a thickness-insensitive cathode interlayer for high performance polymer solar cells

With the power conversion efficiency of polymer solar cells (PSCs) approaching the milestone value of 10%, their instability associated with a low work function metal cathode, particularly in the presence of oxygen and moisture, becomes a critical issue for real applications. To alleviate the air-sensitive problem, two easy-accessible solution-processed, environmentally friendly organic small-molecule cathode interlayers, with perylene diimides (PDI) as the core and amino (PDIN) or amino N-oxide (PDINO) as the terminal substituent, are explored. Benefitting from the extended planar structure of the PDI units, the two interlayer materials show high conductivities of ∼10−5 S cm−1, which make them capable of…