Preventing isomerization of the fused-ring core by introducing a methyl group for efficient non-fullerene acceptors
Preventing isomerization of the fused-ring core by introducing a methyl group for efficient non-fullerene acceptors
复制标题
通过引入有效的非富勒烯受体的甲基来防止稠环核心的异构化
DOI：
10.1039/d1tc02860j
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发表时间：
2021-08-25
影响因子：
6.4
通讯作者：
Tan, Songting
中科院分区：
文献类型：
--
作者：
Deng, Xiong;Zi, Miao;Tan, Songting
在合成小分子受体的环化过程中，苯环上不同的环化反应位点会产生异构体。在此，我们开发了一种结构单元（命名为BTMe），其可以通过将甲基引入苯并[B]苯并[4，5]噻吩并[2，3-d]噻吩（BTBT）单元中来防止环化过程中的异构化。通过改变侧链的长度，合成了两种以BTMe为核的稠环电子受体（BTMe-C6-2F和BTMe-C8-2F）。当它们与施主PM 6共混时，活性层PM 6：BTMe-C8-2F表现出更优异的电荷传输、相形态和π-π堆积，这有利于提高短路电流密度（J（sc））和填充因子（FF）。与BTMe-C6-2F相比，以BTMe-C8-2F为基质的有机太阳能电池（OSC）具有更高的功率转换效率（PCE），达到12.72%，V-oc为0.97 V，J（sc）为19.65 mA cm（-2），FF为66.76%。这些结果表明，通过改变侧链的长度和引入甲基来防止稠环核由于特殊的反应位点而发生异构化，是一种很有前途的获得高性能小分子受体的方法。
Different cyclization reaction sites on the benzene ring will produce isomers during the cyclization process for the synthesis of small-molecule acceptors. Herein, we developed a structural unit (named BTMe) that can prevent isomerization during cyclization by introducing a methyl into a benzo[b]benzo[4,5]thieno[2,3-d]thiophene (BTBT) unit. Two fused ring electron acceptors (BTMe-C6-2F and BTMe-C8-2F) with the BTMe core were synthesized by changing the length of the side chain. When they were blended with donor PM6, the active layer PM6:BTMe-C8-2F exhibited a more excellent charge transport, phase morphology and pi-pi stacking, which are beneficial to improve the short-circuit current density (J(sc)) and fill factor (FF). Compared with BTMe-C6-2F, the organic solar cell (OSC) based on BTMe-C8-2F exhibited a higher power conversion efficiency (PCE) of 12.72% with a V-oc of 0.97 V, a J(sc) of 19.65 mA cm(-2) and a FF of 66.76%. These results proved that it is a promising approach to achieve a high-performance small-molecule acceptor by changing the length of the side chain and introducing methyl groups to prevent the isomerization of the fused ring core owing to special reaction sites.