Ester-substituted Pentathiophene Copolymer based Sky-blue Semitransparent Solar Cells for Building Windows

摘要： For oligothiophene-based donor polymers, the reports of pentathiophene are rare, while other oligothiophene (bi-, ter- and quaterthiophene) have been broadly studied. Here, we synthesized one wide-band-gap (1.88 eV) polymer PFTzTT-3TC, based on ester-substituted pentathiophene and benzotriazole. PFTzTT-3TC: ITIC (1.0:1.0) -based polymer photovoltaic cells exhibited best PCE of 8.21% and Voc of 0.90 V without additive (such as DIO, 1-CN) or post-treatment. These are the highest PCE and Voc for ester-substituted pentathiophene-based devices to date. Furthermore, semitransparent polymer photovoltaic cells with an active blend of PFTzTT-3TC: ITIC (1.0:1.0) demonstrate a similar Voc of 0.89V and a PCE of 6.43% with an AVT of 26.77% and an AT of 30.58% and CIE (0.25, 0.21). The sky-blue of semitransparent devices is useful for photosynthesis in plants and visual comfort in human and make it suitble for building windows.