Heintges Gaël H L, Hendriks Koen H, Colberts Fallon J M, Li Mengmeng, Li Junyu, Janssen René A J
Molecular Materials and Nanosystems, Institute for Complex Molecular Systems, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
Institute for Materials Research (IMO-IMOMEC), Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University Agoralaan, 3590 Diepenbeek Belgium.
RSC Adv. 2019 Mar 15;9(16):8740-8747. doi: 10.1039/c9ra00816k.
The effect of gradually replacing the branched alkyl side chains of a diketopyrrolopyrrole (DPP) conjugated polymer by linear side chains containing branched siloxane end groups on the photovoltaic performance of blends of these polymers with a common fullerene acceptor is investigated. With an increasing proportion of siloxane side chains, the molecular weight and solubility of the polymers decreases. While the siloxane containing polymers exhibit a higher hole mobility in field-effect transistors, their performance in solar cells is less than the polymer with only alkyl sides chains. Using grazing-incidence wide-angle X-ray scattering, transmission electron microscopy, and fluorescence spectroscopy we identify two main reasons for the reduced performance of siloxane containing polymers in solar cells. The first one is a somewhat coarser phase-separated morphology with slightly wider polymer fibers. This is unexpected as often the fiber width is inversely correlated with polymer solubility. The second one is stronger non-radiative decay of the pristine polymers containing siloxane side chains.
研究了用含支链硅氧烷端基的线性侧链逐步取代二酮吡咯并吡咯（DPP）共轭聚合物的支链烷基侧链，对这些聚合物与常见富勒烯受体共混物光伏性能的影响。随着硅氧烷侧链比例的增加，聚合物的分子量和溶解度降低。虽然含硅氧烷的聚合物在场效应晶体管中表现出较高的空穴迁移率，但其在太阳能电池中的性能低于仅含烷基侧链的聚合物。通过掠入射广角X射线散射、透射电子显微镜和荧光光谱，我们确定了含硅氧烷聚合物在太阳能电池中性能降低的两个主要原因。第一个原因是相分离形态略显粗糙，聚合物纤维略宽。这出乎意料，因为通常纤维宽度与聚合物溶解度呈负相关。第二个原因是含硅氧烷侧链的原始聚合物的非辐射衰减更强。
