Leng Shifeng, Hao Tianyu, Zhou Guanqing, Zhu Lei, Zhong Wenkai, Yang Yankang, Zhang Ming, Xu Jinqiu, Zhan Junzhe, Zhou Zichun, Chen Jiajun, Lu Shirong, Tang Zheng, Shi Zhiwen, Zhu Haiming, Zhang Yongming, Liu Feng
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
Adv Sci (Weinh). 2022 Feb;9(6):e2104613. doi: 10.1002/advs.202104613. Epub 2022 Jan 12.
The donor/acceptor interaction in non-fullerene organic photovoltaics leads to the mixing domain that dictates the morphology and electronic structure of the blended thin film. Initiative effort is paid to understand how these domain properties affect the device performances on high-efficiency PM6:Y6 blends. Different fullerenes acceptors are used to manipulate the feature of mixing domain. It is seen that a tight packing in the mixing region is critical, which could effectively enhance the hole transfer and lead to the enlarged and narrow electron density of state (DOS). As a result, short-circuit current (J ) and fill factor (FF) are improved. The distribution of DOS and energy levels strongly influences open-circuit voltage (V ). The raised filling state of electron Fermi level is seen to be key in determining device V . Energy disorder is found to be a key factor to energy loss, which is highly correlated with the intermolecular distance in the mixing region. A 17.53% efficiency is obtained for optimized ternary devices, which is the highest value for similar systems. The current results indicate that a delicate optimization of the mixing domain property is an effective route to improve the V , J , and FF simultaneously, which provides new guidelines for morphology control toward high-performance organic solar cells.
非富勒烯有机光伏器件中的供体/受体相互作用会导致混合域的形成，该混合域决定了混合薄膜的形态和电子结构。人们付出了积极的努力来理解这些域特性如何影响高效PM6:Y6混合体系的器件性能。使用不同的富勒烯受体来控制混合域的特征。可以看出，混合区域中的紧密堆积至关重要，这可以有效地增强空穴传输并导致态密度（DOS）增大且变窄。结果，短路电流（J）和填充因子（FF）得到改善。DOS和能级的分布强烈影响开路电压（V）。电子费米能级的升高填充状态被认为是决定器件V的关键。发现能量无序是能量损失的关键因素，这与混合区域中的分子间距离高度相关。优化后的三元器件效率达到17.53%，这是类似体系中的最高值。目前的结果表明，对混合域特性进行精细优化是同时提高V、J和FF的有效途径，这为高性能有机太阳能电池的形态控制提供了新的指导方针。
