Oligoselenophene Derivatives Functionalized with a Diketopyrrolopyrrole Core for Molecular Bulk Heterojunction Solar Cells

Solution-processable oligoselenophenes functionalized with diketopyrrolopyrrole cores have been synthesized for use as the donor material in bulk heterojunction solar cells. The optical absorption of these materials extends to the edge of the visible spectrum. Power conversion efficiencies of 1.53 ± 0.04% for DPPS and 0.84 ± 0.04% for DPPDS were obtained under simulated 100 mW/cm2 AM 1.5G irradiation for devices when PC61BM was used as an acceptor. DPPS showed hole mobilities of 4 × 10−5 cm2/(V s) and a peak external quantum efficiency (EQE) of 25%, while DPPDS showed hole mobilities of 2 × 10−5 cm2/(V s) and a peak EQE of 19%. To the best of our knowledge, these are the first oligoselenophenes that have been reported in molecular bulk heterojunction solar cells and this study could serve as a springboard for the design and optimization of high-performance selenophene-containing photovoltaics.