| 초록 |
In this study, a series of semi-crystalline PPDT2FBT polymers with different number-average molecular weights (Mn) (PPDT2FBTL: Mn = 12 kg/mol; PPDT2FBTM: Mn= 24 kg/mol; PPDT2FBTH: Mn= 40 kg/mol) were synthesized and their photovoltaic properties as electron donors for all-polymer solar cells (all-PSCs) with P(NDI2OD-T2) acceptor were studied. The Mn effect of PPDT2FBT on the structural, morphological, electrical and photovoltaic properties was systematically investigated. In particular, tuning the Mn induced dramatic effects on the aggregation behaviors of the polymers and their bulk heterojunction morphology of all-PSCs, which was thoroughly examined by grazing incident X-ray scattering, resonant soft X-ray scattering, and other microscopy measurements. High Mn PPDT2FBTH promoted a strong “face-on” geometry in the blend film, suppressed the formation of an excessively large crystalline domain, and facilitated molecularly-intermixed phases with P(NDI2OD-T2). |
