School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, P.R. China.
ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
J Phys Chem Lett. 2023 Jul 6;14(26):6051-6060. doi: 10.1021/acs.jpclett.3c01004. Epub 2023 Jun 26.
Organic photovoltaics (OPVs) are regarded as one of the most promising candidates for various outdoor and indoor application scenarios. The development and application of nonfullerene acceptors have pushed power conversion efficiencies (PCEs) of single-junction cells to exceed 19%, and values approaching 20% are within sight. This progress has resulted in some unexpected photophysical observations deserving more in-depth spectroscopic research. In this Perspective, we have summarized recent photophysical advances in accordance with results of ultrafast spectroscopy in our and other groups and provide our point of view on multiple-time scale exciton dynamics involving the following aspects: long-range exciton diffusion driven by dual Förster resonance energy transfer, origins of driving force for hole transfer under small energy offsets, trap-induced charge recombination in outdoor and indoor OPVs, and a picture of real-time evolution of excitons and charge carriers regarding stability. Moreover, our understanding of the photophysical property-function relationship is proposed in state-of-the-art OPVs. Finally, we point out the remaining challenges devoted to the further development of versatile OPVs.
有机光伏（OPV）被认为是各种户外和室内应用场景的最有前途的候选者之一。非富勒烯受体的发展和应用将单结电池的功率转换效率（PCE）推高至超过 19%，而接近 20%的效率也即将实现。这一进展导致了一些意外的光物理观察结果，值得进行更深入的光谱研究。在本观点中，我们根据超快光谱在我们和其他小组的结果总结了最近的光物理进展，并就涉及以下方面的多时间尺度激子动力学提供了我们的观点：双Förster 共振能量转移驱动的长程激子扩散、小能量偏移下空穴转移的驱动力起源、户外和室内 OPV 中的陷阱诱导电荷复合，以及关于稳定性的激子和电荷载流子实时演化的图景。此外，我们提出了对最先进的 OPV 中光物理性质-功能关系的理解。最后，我们指出了致力于进一步开发多功能 OPV 的剩余挑战。
