Competition between triplet pair formation and excimer-like recombination controls singlet fission yield
Competition between triplet pair formation and excimer-like recombination controls singlet fission yield
复制标题
DOI：
10.1016/j.xcrp.2021.100339
复制
发表时间：
2021-02-24
影响因子：
8.9
通讯作者：
Puttisong, Yuttapoom
中科院分区：
文献类型：
--
作者：
Huang, Yuqing;Buyanova, Irina A.;Puttisong, Yuttapoom
单重态裂变的最终目标是每个光激发的单重态激子S-1将产生具有单位产率的两个三重态激子。然而，单重态裂变现在被认为是复杂的，涉及不同自旋多重性的亮/暗激发态。确定这些状态的作用对于优化单线态裂变产额至关重要，但由于其难以捉摸的光谱特征而很困难。在这里，我们开发了一个实验协议的基础上，一个精致的磁光探针访问各种激发态的快速时间演化。在二苯基己三烯晶体中，S-1经历了两个竞争过程：形成两个交换能不同的暗三重态中间体之一或形成亮态S-x，表现出类似准分子的延迟发光。我们的结果提供了一个清晰的单重态裂变竞争事件的图像，这有利于高产额单重态裂变材料的开发和剪裁。
The ultimate goal for singlet fission is that each photo-excited singlet exciton, S-1, will result in two triplet excitons with unity yield. However, the singlet fission is now recognized to be complicated, involving bright/dark excited states of different spin multiplicity. Identifying the role of such states is vital to optimize singlet fission yield but difficult due to their elusive spectral signature. Here, we develop an experimental protocol based on a refined magneto-optical probe to access the fast time evolution of various excited states. In diphenylhexatriene crystal, the S-1 is found to undergo two competing processes-to form one of the two dark triplet pair intermediates having different exchange energies or to form a bright state, S-x, exhibiting excimer-like delayed photoluminescence. Our result provides a clear picture of a competition event in singlet fission, which is beneficial for the development and tailoring of singlet fission materials with high yield.