College of Physics, Hebei Normal University, Shijiazhuang 050016, China.
J Chem Phys. 2009 Dec 28;131(24):244502. doi: 10.1063/1.3274680.
Both polarons and excitons, which are composite particles with internal lattice structure, play an important role in the transport and light-emitting properties of conjugated polymers for the use in, e.g., polymer based light-emitting diodes (LEDs). The scattering and recombination processes between a triplet exciton and a polaron are investigated using a nonadiabatic evolution method based on an extended Su-Schrieffer-Heeger model including interchain interactions. The results show that an excited polaron state can be formed, besides a triplet exciton is converted into a singlet exciton by the polaron. Moreover, the yields of both the singlet exciton and the excited polaron states increase with increasing interchain coupling strength. The excited polaron is luminescent due to radiative decay as is the singlet exciton. Therefore, our results indicate that the quantum efficiency of polymer LEDs could be enhanced by polaron-exciton recombination.
激子和极化子都是具有晶格结构的复合粒子，它们在用于聚合物发光二极管（LED）等的共轭聚合物的输运和发光性质中起着重要作用。本文采用基于扩展 Su-Schrieffer-Heeger 模型的非绝热演化方法，研究了三重激子和极化子之间的散射和复合过程，该模型包含了链间相互作用。结果表明，除了三重激子转化为单重激子之外，还可以形成激发极化子态。此外，单重激子态和激发极化子态的产率都随着链间耦合强度的增加而增加。由于辐射衰变，激发极化子和单重激子都是发光的。因此，我们的结果表明，极化子-激子复合可以提高聚合物 LED 的量子效率。
