Side chain engineering has been commonly recognized to be a simple and effective strategy in designing organic photovoltaic materials and increasing power conversion efficiencies. Different from recent traditional side chain modulation, this work presented the design and synthesis of a family of fresh hybrid side chain by combining the relatively rigid cyclic and flexible alkyl chain. To be specific, cyclopentane, cyclohexane and cycloheptane were introduced to the tail of the alkyl side chain, through which novel polymer donors D18-C6Cp, D18-C6Ch and D18-C6Chp were prepared based on the excellent skeleton of D18. In comparison with simplex cyclic or branched chain, hybrid side chains with preferential conformations were capable of impacting the self-assembling characteristics and facilitating the interpenetrating networks of blend films, thereby contributing to high-efficiency charge transport, lower energy loss, and inhibited charge recombination. Strikingly, the D18-C6Ch:L8-Bo-based single junction OPV cells reveal a prominent FF of 78.7 %, and a V_oc of 0.91 V with the maximum PCE up to 18.2 %. This work exhibits an effective hybrid side chain engineering to synergistically tune the self-assembly properties and finally improve organic photovoltaic performance, which would be a broad potential in developing novel materials in the field of organic optoelectronics.

侧链工程已被普遍认为是设计有机光伏材料和提高功率转换效率的一种简单有效的策略。与最近的传统侧链调制不同，这项工作通过结合相对刚性的环状和柔性烷基链，提出了一系列新鲜杂化侧链的设计和合成。具体而言，将环戊烷、环己烷和环庚烷引入烷基侧链的尾部，基于D18的优良骨架制备了新型聚合物供体D18-C6Cp、D18-C6Ch和D18-C6Chp。与单环或支链相比，具有优先构象的杂化侧链能够影响自组装特性并促进共混膜的互穿网络，从而有助于高效的电荷传输，降低能量损失并抑制电荷复合。引人注目的是，基于 D18-C6Ch:L8-Bo 的单结 OPV 电池显示出 78.7% 的显着 FF，以及V _oc为 0.91 V，最大 PCE 高达 18.2 %。这项工作展示了一种有效的混合侧链工程，可以协同调节自组装性能，最终提高有机光伏性能，这将在有机光电子领域开发新型材料方面具有广阔的潜力。