Generating Light from Upper Excited Triplet States: A Contribution to the Indirect Singlet Yield of a Polymer OLED, Helping to Exceed the 25% Singlet Exciton Limit.
Generating Light from Upper Excited Triplet States: A Contribution to the Indirect Singlet Yield of a Polymer OLED, Helping to Exceed the 25% Singlet Exciton Limit.
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DOI：
10.1002/advs.201500221
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发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Monkman AP
中科院分区：
文献类型：
--
作者：
Jankus V;Aydemir M;Dias FB;Monkman AP
在过去的十年里，有机发光二极管产生光的机制逐渐被阐明。三重态湮灭的作用已经证明了如何超越“自旋统计极限”，但它不能解释最有效的设备产生的所有光。在这里，进一步的机制，证明了高激发三重态也可以有助于间接单线态的产生和延迟荧光。由于在器件中这些TN态的数量很大，因此这种间接辐射衰变通道可以贡献从器件测量的总辐射的相当大的一部分。链内和链间电荷转移状态的作用是支持这一机制的关键。
The mechanisms by which light is generated in an organic light emitting diode have slowly been elucidated over the last ten years. The role of triplet annihilation has demonstrated how the “spin statistical limit” can be surpassed, but it cannot account for all light produced in the most efficient devices. Here, a further mechanism is demonstrated by which upper excited triplet states can also contribute to indirect singlet production and delayed fluorescence. Since in a device the population of these TN states is large, this indirect radiative decay channel can contribute a sizeable fraction of the total emission measured from a device. The role of intra‐ and interchain charge transfer states is critical in underpinning this mechanism.