Piland Geoffrey B, Burdett Jonathan J, Dillon Robert J, Bardeen Christopher J
Department of Chemistry, University of California, Riverside, Riverside, California 92506, United States.
J Phys Chem Lett. 2014 Jul 3;5(13):2312-9. doi: 10.1021/jz500676c. Epub 2014 Jun 21.
Singlet fission, in which an initially excited singlet state spontaneously splits into a pair of triplet excitons, is a process that can potentially boost the efficiency of solar energy conversion. The separate electronic bands in organic semiconductors make them especially useful for dividing a high-energy singlet exciton into a pair of lower-energy triplet excitons. Recent experiments illustrate the role of spin coherence in fission, while kinetic models are used to describe how triplet and singlet states interact on longer time scales. Despite insights gained from recent experiments, the detailed structure and dynamics of the electronic states involved in the initial step of singlet fission remain active areas of investigation. On longer time scales, finding ways to efficiently harvest the triplet excitons will be an important challenge for making devices based on this phenomenon. A full understanding of singlet fission requires consideration of a sequence of photophysical events (decoherence, relaxation, and diffusion) occurring on different time scales.
单重态裂变是指一个初始激发的单重态自发地分裂为一对三重态激子的过程，这一过程有可能提高太阳能转换效率。有机半导体中分离的电子能带使其特别适用于将高能单重态激子分裂为一对低能三重态激子。最近的实验阐明了自旋相干在裂变中的作用，同时动力学模型被用于描述三重态和单重态在更长时间尺度上是如何相互作用的。尽管从最近的实验中获得了一些见解，但单重态裂变初始步骤中涉及的电子态的详细结构和动力学仍是活跃的研究领域。在更长的时间尺度上，找到有效收集三重态激子的方法将是基于这一现象制造器件面临的一项重要挑战。对单重态裂变的全面理解需要考虑在不同时间尺度上发生的一系列光物理事件（退相干、弛豫和扩散）。
