Wei Weifei, Zhang Cai'e, Chen Zhanxiang, Chen Wei, Ran Guangliu, Pan Guangjiu, Zhang Wenkai, Müller-Buschbaum Peter, Bo Zhishan, Yang Chuluo, Luo Zhenghui
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, 518060, Shenzhen, China.
Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, 100875, Beijing, China.
Angew Chem Int Ed Engl. 2024 Feb 5;63(6):e202315625. doi: 10.1002/anie.202315625. Epub 2024 Jan 2.
Utilizing intermolecular hydrogen-bonding interactions stands for an effective approach in advancing the efficiency and stability of small-molecule acceptors (SMAs) for polymer solar cells. Herein, we synthesized three SMAs (Qo1, Qo2, and Qo3) using indeno[1,2-b]quinoxalin-11-one (Qox) as the electron-deficient group, with the incorporation of a methylation strategy. Through crystallographic analysis, it is observed that two Qox-based methylated acceptors (Qo2 and Qo3) exhibit multiple hydrogen bond-assisted 3D network transport structures, in contrast to the 2D transport structure observed in gem-dichlorinated counterpart (Qo4). Notably, Qo2 exhibits multiple and stronger hydrogen-bonding interactions compared with Qo3. Consequently, PM6 : Qo2 device realizes the highest power conversion efficiency (PCE) of 18.4 %, surpassing the efficiencies of devices based on Qo1 (15.8 %), Qo3 (16.7 %), and Qo4 (2.4 %). This remarkable PCE in PM6 : Qo2 device can be primarily ascribed to the enhanced donor-acceptor miscibility, more favorable medium structure, and more efficient charge transfer and collection behavior. Moreover, the PM6 : Qo2 device demonstrates exceptional thermal stability, retaining 82.8 % of its initial PCE after undergoing annealing at 65 °C for 250 hours. Our research showcases that precise methylation, particularly targeting the formation of intermolecular hydrogen-bonding interactions to tune crystal packing patterns, represents a promising strategy in the molecular design of efficient and stable SMAs.
利用分子间氢键相互作用是提高聚合物太阳能电池小分子受体（SMA）效率和稳定性的有效方法。在此，我们以茚并[1,2-b]喹喔啉-11-酮（Qox）为缺电子基团，采用甲基化策略合成了三种SMA（Qo1、Qo2和Qo3）。通过晶体学分析发现，与二氯代类似物（Qo4）中观察到的二维传输结构相比，两种基于Qox的甲基化受体（Qo2和Qo3）呈现出多重氢键辅助的三维网络传输结构。值得注意的是，与Qo3相比，Qo2表现出更多且更强的氢键相互作用。因此，PM6 : Qo2器件实现了18.4%的最高功率转换效率（PCE），超过了基于Qo1（15.8%）、Qo3（16.7%）和Qo4（2.4%）的器件效率。PM6 : Qo2器件中这一显著的PCE主要归因于供体 - 受体混溶性的增强、更有利的介质结构以及更有效的电荷转移和收集行为。此外，PM6 : Qo2器件表现出出色的热稳定性，在65 °C退火250小时后仍保留其初始PCE的82.8%。我们的研究表明，精确的甲基化，特别是针对分子间氢键相互作用的形成来调整晶体堆积模式，是高效稳定SMA分子设计中的一种有前景的策略。
