Wang Jing, Jiang Xudong, Wu Hongbo, Feng Guitao, Wu Hanyu, Li Junyu, Yi Yuanping, Feng Xunda, Ma Zaifei, Li Weiwei, Vandewal Koen, Tang Zheng
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Center for Advanced Low-dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, P. R. China.
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.
Nat Commun. 2021 Nov 18;12(1):6679. doi: 10.1038/s41467-021-26995-1.
The high voltage losses ([Formula: see text]), originating from inevitable electron-phonon coupling in organic materials, limit the power conversion efficiency of organic solar cells to lower values than that of inorganic or perovskite solar cells. In this work, we demonstrate that this [Formula: see text] can in fact be suppressed by controlling the spacing between the donor (D) and the acceptor (A) materials (DA spacing). We show that in typical organic solar cells, the DA spacing is generally too small, being the origin of the too-fast non-radiative decay of charge carriers ([Formula: see text]), and it can be increased by engineering the non-conjugated groups, i.e., alkyl chain spacers in single component DA systems and side chains in high-efficiency bulk-heterojunction systems. Increasing DA spacing allows us to realize significantly reduced [Formula: see text] and improved device voltage. This points out a new research direction for breaking the performance bottleneck of organic solar cells.
高压损耗（[公式：见原文]）源于有机材料中不可避免的电子 - 声子耦合，这使得有机太阳能电池的功率转换效率低于无机或钙钛矿太阳能电池。在这项工作中，我们证明通过控制供体（D）和受体（A）材料之间的间距（DA间距），实际上可以抑制这种[公式：见原文]。我们表明，在典型的有机太阳能电池中，DA间距通常过小，这是电荷载流子非辐射衰减过快（[公式：见原文]）的根源，并且可以通过设计非共轭基团来增加DA间距，即在单组分DA系统中的烷基链间隔基和高效体相异质结系统中的侧链。增加DA间距使我们能够实现显著降低的[公式：见原文]并提高器件电压。这为突破有机太阳能电池的性能瓶颈指出了一个新的研究方向。
