近日，南开大学陈永胜团队实现了通过空间分离HOMO和LUMO来调节高性能有机光伏接收器的单重态-三重态能隙。这一研究成果于2025年7月1日发表在《德国应用化学》杂志上。

减少有机光伏（OPV）分子的单三重态能隙（EST），可以通过调节低空三重态（T1）和/或激发态（S1）来减少非辐射复合，从而降低其器件中的能量损失（loss）和增加开路电压。然而，如何设计具有小EST和高性能的非富勒烯受体是一个挑战。

针对这一问题，研究组合成了YDF、YTF和YTF-H。其中，基于部分空间分离HOMO和LUMO的YDF器件的功率转换效率（PCE）高达20.04%，是二元系统中效率最高的器件之一。对于YTF和YTF-H来说，它们完全空间分离的HOMO和LUMO确实导致了由低空S1态主导的EST的大幅降低，以及高性能OPV所需的优异的电荷迁移率和光吸收。

但由于强S1- 0耦合（PCE <1.5%），它们的低S1态导致了多次非辐射重组。这些结果表明，未来设计具有小EST的高性能分子应该避免S1的急剧下降，理想的情况是提高T1状态，从而减轻能隙定律。

附：英文原文

Title: Regulate the Singlet–triplet Energy Gap by Spatially Separating HOMO and LUMO for High Performance Organic Photovoltaic Acceptors

Author: Guangkun Song, Tengfei He, Ruohan Wang, Yanni Ouyang, Nakul Jain, Saisai Liu, Bin Kan, Yujie Shang, Jiaqi Li, Xingkai Wang, Zhaoyang Yao, Xiangjian Wan, Chenxi Li, Wei Ma, Yan Zhao, Guankui Long, Chunfeng Zhang, Feng Gao, Yongsheng Chen

Issue&Volume: 2025-07-01

Abstract: Reducing the single-triplet energy gap (EST) for organic photovoltaic (OPV) molecules has been proposed to be able to reduce the nonradiative recombination by tuning low-lying triplet state (T1) and/or the excited state (S1), thus reducing the energy loss (Eloss) and increasing the open-circuit voltage in their devices. However, how to design the non-fullerene acceptor with small EST and high performance is challenging. Aiming to address this issue, YDF, YTF and YTF-H were synthesized. Among them, device based on YDF with partially spatially separating HOMO and LUMO exhibits a much higher power conversion efficiency (PCE) of 20.04%, which is one of the most efficient efficiencies for binary systems. For YTF and YTF-H, their completely spatially separated HOMO and LUMO indeed leads a much reducing of EST caused by low-lying S1 state, together with excellent charge mobility and light absorption, required for higher performance OPV. But their low S1 state cause several non-radiative recombination due to strong S1-S0 coupling (PCE <1.5%). These results indicate that future design to have high performance molecules with small EST should avoid the sharp decrease in S1, and the ideal scenario would be to elevate the T1 state, thereby mitigating the energy gap law.

DOI: 10.1002/anie.202506357

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202506357