Abstract

Nonfullerene acceptors are being investigated for use in polymer solar cells (PSCs), with their advantages of extending the absorption range, reducing the energy loss and therefore enhancing the power conversion efficiency (PCE). However, to further boost the PCE, mobilities of these nonfullerene acceptors should be improved. For nonfullerene acceptors, the π–π stacking distance between cofacially stacked molecules significantly affects their mobility. Here, we demonstrate a strategy to increase the mobility of heteroheptacene-based nonfullerene acceptors by reducing their π–π stacking distances via control over the bulkiness of lateral side chains. Incorporation of 2-butyloctyl substituents into the nonfullerene acceptor (M36) leads to an increased mobility with a reduced π–π stacking distance of 3.45 Å. Consequently, M36 affords an enhanced PCE of 16%, which is the highest among all acceptor-donor-acceptor-type nonfullerene acceptors to date. This strategy of control over the bulkiness of side chains on nonfullerene acceptors should aid the development of more efficient PSCs.

中文翻译：

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用于 16% 效率聚合物太阳能电池的基于杂七苯的非富勒烯受体的 π-π 堆积控制

摘要

非富勒烯受体正在研究用于聚合物太阳能电池 (PSC)，其优点是可扩展吸收范围、减少能量损失并因此提高功率转换效率 (PCE)。然而，为了进一步提高 PCE，应提高这些非富勒烯受体的迁移率。对于非富勒烯受体，共面堆叠分子之间的 π-π 堆叠距离显着影响它们的迁移率。在这里，我们展示了一种策略，通过控制横向侧链的体积来减少它们的 π-π 堆积距离，从而提高基于杂七烯的非富勒烯受体的迁移率。将 2-丁基辛基取代基引入非富勒烯受体 (M36) 导致迁移率增加，π-π 堆积距离减小 3.45 Å。最后，M36 提供了 16% 的增强 PCE，这是迄今为止所有受体-供体-受体型非富勒烯受体中最高的。这种控制非富勒烯受体侧链体积的策略应该有助于开发更有效的 PSC。