西安交通大学凡群平等报道了单向侧链工程构建效率为19.23%，具有低能量损失和高效电荷转移的有机太阳能电池双不对称受体。2023年7月18日出版的《德国应用化学》发表了这项成果。

实现高开路电压（VOC）和短路电流密度（JSC）以提高功率转换效率（PCE），是有机太阳能电池（OSCs）的主要挑战，其中通常会发生高能量损耗（Eloss）和低效的电荷转移。

该文中，研究人员开发了三种新的Y系列受体，即单不对称asy-YC11和双不对称双-asy-YC9和双-asy-YC12。它们具有相同的不对称D1AD2（D1=噻吩并[3,2-b]噻吩和D2=硒代苯并[3,2-2]噻吩）稠核，但在D1侧具有不同的单向侧链，能够精细调节分子性质，如分子间相互作用、堆积模式和结晶度。在二元共混物中，PM6:bi-assy-YC12共混物比PM6:asy-YC9和PM6:bi-Assy-YC11共混物具有更好的形态、适当的相分离和更高的有序堆积。

因此，基于PM6:bi-assy-YC12的OSCs提供了17.16%的较高PCE，同时具有高VOC和JSC，这是由于降低了Eloss和有效的电荷转移特性。受高VOC和强近红外吸收的启发，将双-asy-YC12引入高效的二元PM6:L8-BO中，构建三元OSCs。得益于加宽的吸收、优化的形态和进一步最小化的Eloss，基于PM6:L8-BO:bi-asy-YC12的OSCs实现了19.23%的冠军PCE，这是这些无退火器件中效率最高的器件之一。

研究人员开发的用于构建双不对称Y系列受体的单向侧链工程，为提高OSCs的PCE提供了一种方法。

附：英文原文

Title: Unidirectional Sidechain Engineering to Construct Dual-Asymmetric Acceptors for 19.23% Efficiency Organic Solar Cells with Low Energy Loss and Efficient Charge Transfer

Author: Qunping Fan, Rui Ma, Jie Yang, Jingshun Gao, Hai Bai, Wenyan Su, Zezhou Liang, Yue Wu, Lingxiao Tang, Yuxiang Li, Qiang Wu, Kun Wang, Lihe Yan, Rui Zhang, Feng Gao, Gang Li, Wei Ma

Issue&Volume: 2023-07-18

Abstract: Achieving both high open-circuit voltage (VOC) and short-circuit current density (JSC) to boost power-conversion efficiency (PCE) is a major challenge for organic solar cells (OSCs), wherein high energy loss (Eloss) and inefficient charge transfer usually take place. Here, three new Y-series acceptors of mono-asymmetric asy-YC11 and dual-asymmetric bi-asy-YC9 and bi-asy-YC12 are developed. They share the same asymmetric D1AD2 (D1=thieno[3,2-b]thiophene and D2=selenopheno[3,2-b]thiophene) fused-core but have different unidirectional sidechain on D1 side, allowing fine-tuned molecular properties, such as intermolecular interaction, packing pattern, and crystallinity. Among the binary blends, the PM6:bi-asy-YC12 one has better morphology with appropriate phase separation and higher order packing than the PM6:asy-YC9 and PM6:bi-asy-YC11 ones. Therefore, the PM6:bi-asy-YC12-based OSCs offer a higher PCE of 17.16% with both high VOC and JSC, due to the reduced Eloss and efficient charge transfer properties. Inspired by the high VOC and strong NIR-absorption, bi-asy-YC12 is introduced into efficient binary PM6:L8-BO to construct  ternary OSCs. Thanks to the broadened absorption, optimized morphology, and furtherly minimized Eloss, the PM6:L8-BO:bi-asy-YC12-based OSCs achieve a champion PCE of 19.23%, which is one of the highest efficiencies among these annealing-free devices. Our developed unidirectional sidechain engineering for constructing bi-asymmetric Y-series acceptors provides an approach to boost PCE of OSCs.

DOI: 10.1002/anie.202308307

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202308307