Controlling random configuration of thiophene units for mechanically stable solar cells.
발표자
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초록
내용
In this study, we study on the relationship between morphologies and optoelectronic/mechanical properties of polymer solar cells. Introducing thiophene unit as a regular (PffBT-4T) or random (PffBT-RT4) is needed for the study of developing flexibility. The difference of the PffBT-4T and PffBT-RT4 is only configuration, so the energy level, which has effect on charge transport and recombination in the device, of both polymers are equal. PffBT-RT4 exhibits low crystallinity and shorter π-π distance than PffBT-4T, and it leads to the high efficiency of 8.84% comparing to PffBT-4T (7.25%) due to improved interchain charge transporting abilities. In addition, PffBT-RT4 based flexible solar cells showed better mechanical robustness, maintaining its initial level after 100 bending cycles at a bending radius of 4.5 mm. Moreover, for the PffBT-RT4:PC71BM film, the out-of-plane (100) peak intensity decreased only slightly even after 100 stretches.