Spin signatures of exchange-coupled triplet pairs formed by singlet fission
Spin signatures of exchange-coupled triplet pairs formed by singlet fission
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DOI：
10.1103/physrevb.94.045204
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发表时间：
2016-07-11
影响因子：
3.7
通讯作者：
Greenham, Neil C.
中科院分区：
文献类型：
--
作者：
Bayliss, Sam L.;Weiss, Leah R.;Greenham, Neil C.
研究了交换相互作用对单线态裂变材料中依赖磁场的光致发光的影响。我们表明，对于强相互作用的三重态激子对（三重态交换相互作用大于三重态自旋偶极相互作用），量子跳动和磁场效应消失，除了在特定的磁场中，单重态和五重态能级被一个能级反交叉混合。我们描述了这些效应，并表明没有磁场效应或零场量子拍并不一定意味着裂变不发生。这些结果要求重新考虑被认为是单线态裂变标志的观察结果，并证明如何通过磁光致发光实验来测量相互作用的三重态对的自旋相干性和交换耦合。
We study the effect of an exchange interaction on the magnetic-field-dependent photoluminescence in singlet fission materials. We show that, for strongly interacting triplet exciton pairs (intertriplet exchange interaction greater than the intratriplet spin-dipolar interaction), quantum beating and magnetic-field effects vanish apart from at specific magnetic fields where singlet and quintet levels are mixed by a level anticrossing. We characterize these effects and show that the absence of a magnetic-field effect or zero-field quantum beats does not necessarily mean that fission is inoperative. These results call for a reconsideration of the observations that are considered hallmarks of singlet fission and demonstrate how the spin coherence and exchange coupling of interacting triplet pairs can be measured through magneto-photoluminescence experiments.