Layer by layer solution processed organic solar cells based on a small molecule donor and a polymer acceptor

Abstract

Layer by layer (LL) solution processed organic solar cells (OSCs) were fabricated using a squaraine small molecule (DIB-SQ) as a donor and a perylene diimide polymer (PPDIDTT) as an acceptor. DIB-SQ and PPDIDTT exhibited matched energy levels and complementary absorption. Compared with the blend structure, the LL devices exhibited better morphology for exciton dissociation and reducing charge recombination. Moreover, efficient vertical phase separation can also be achieved using the LL method, which is beneficial for charge transport and collection at the appropriate electrodes. The traditional blend OSCs exhibited no photovoltaic response, while the LL devices yielded power conversion efficiencies of up to 1.12%.