Identifying the efficient inter-conversion between singlet and triplet charge-transfer states by magneto-electroluminescence study

被引：39

作者：

Chen, Ping ^{[1
]}

Peng, Qiming ^{[1
]}

Yao, Liang ^{[1
]}

Gao, Na ^{[1
]}

Li, Feng ^{[1
]}

机构：

[1] Jilin Univ, State Key Lab Supramol Struct & Mat, Changchun 130012, Peoples R China

来源：

APPLIED PHYSICS LETTERS | 2013年 / 102卷 / 06期

关键词：

LIGHT-EMITTING DEVICES; EMISSION; DIODES;

D O I：

10.1063/1.4791562

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Using the magneto-electroluminescence (MEL) as a tool, we demonstrated the efficient inter-conversion between singlet and triplet charge-transfer (CT) states in exciplex-based organic light-emitting diodes (OLEDs). Results show that the MEL of exciplex-based device is larger than that of exciton-based device by a factor of 3.2. The emission of exciplex-based devices comes from the direct intermolecular electron-hole pair recombination and their spin exchange energy is much smaller, which causes the efficient inter-conversion between singlet and triplet states. This argument was supported by the consistent evolutions of the MEL and EL spectra versus applied bias and donor concentrations. Finally, the bandgap effects on the MEL as well as the external quantum efficiency of exciplex-based devices were discussed. Our findings of MEL may offer a feasible way to unravel underlying mechanisms that limit the EL efficiency in the OLEDs. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4791562]

引用

页数：4

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