Liang Shijie, Jiang Xudong, Xiao Chengyi, Li Cheng, Chen Qiaomei, Li Weiwei
Beijing Advanced Innovation Center for Soft Matter Science and Engineering & State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
Acc Chem Res. 2021 May 4;54(9):2227-2237. doi: 10.1021/acs.accounts.1c00070. Epub 2021 Apr 14.
ConspectusConjugated polymers for application in organic solar cells (OSCs) have been developed from poly(phenylenevinylene) to poly(3-hexylthiophene) and then to "donor-acceptor" structures, providing power conversion efficiencies (PCEs) over 18% when blending with the electron acceptor as a two-component photoactive layer. Besides, graft-structural double-cable conjugated polymers that use an electron donor as conjugated backbones and an electron acceptor as pendant side units are one kind of conjugated polymer, in which charge carriers are generated in a single polymer. Therefore, double-cable conjugated polymers can be used as a single photoactive layer in single-component OSCs (SCOSCs). The covalently linked electron donor and acceptor enable double-cable polymers to maintain stable microstructures during long-term operation compared to two-component systems, which is very important for OSCs toward large-area applications. However, SCOSCs based on double-cable conjugated polymers provided PCEs below 3% in a long period, which is lagging far behind PCEs of two-component OSCs. The key reason for this is the limited number of chemical structures and the difficulty to tune the morphology in these polymers.In this Account, we provide an overview about our efforts on developing new double-cable conjugated polymers with rylene diimides as side units, and how to realize high PCEs in SCOSC devices. The studies start from developing a "functionalization-polymerization" method to synthesize the polymers containing rylene diimide acceptors, so that large amounts of double-cable conjugated polymers with distinct physical and electrochemical properties were obtained. Then, we will discuss how to control the nanophase separation in the crystalline region and optimize the miscibility in the amorphous region of double-cable polymers, simultaneously facilitating exciton dissociation and charge transport. With these efforts, a high PCE of 8.4% has been obtained, representing the record PCE in SCOSCs. In addition, the physical process and the stability of SCOSCs will be discussed. We hope that this account will inspire many innovative studies in this field and push the PCEs of SCOSCs to a new stage.
综述
用于有机太阳能电池（OSC）的共轭聚合物已从聚对苯撑乙烯发展到聚（3 - 己基噻吩），再到“供体 - 受体”结构，当与电子受体混合作为双组分光活性层时，其功率转换效率（PCE）超过18%。此外，以电子供体为共轭主链、电子受体为侧链单元的接枝结构双电缆共轭聚合物是共轭聚合物的一种，其中电荷载流子在单一聚合物中产生。因此，双电缆共轭聚合物可用于单组分OSC（SCOSC）中的单光活性层。与双组分体系相比，共价连接的电子供体和受体使双电缆聚合物在长期运行过程中能够保持稳定的微观结构，这对于面向大面积应用的OSC非常重要。然而，基于双电缆共轭聚合物的SCOSC长期以来的PCE低于3%，远远落后于双组分OSC的PCE。其关键原因是这些聚合物的化学结构数量有限以及调节形态的困难。
在本综述中，我们概述了我们在开发以苝二酰亚胺为侧链单元的新型双电缆共轭聚合物以及如何在SCOSC器件中实现高PCE方面所做的努力。研究始于开发一种“功能化 - 聚合”方法来合成含有苝二酰亚胺受体的聚合物，从而获得了大量具有不同物理和电化学性质的双电缆共轭聚合物。然后，我们将讨论如何控制双电缆聚合物结晶区域的纳米相分离并优化非晶区域的混溶性，同时促进激子解离和电荷传输。通过这些努力，已获得了8.4%的高PCE，代表了SCOSC中的最高PCE记录。此外，还将讨论SCOSC的物理过程和稳定性。我们希望本综述能激发该领域的许多创新性研究，并将SCOSC的PCE推向一个新的阶段。
