High efficiency yellow fluorescent organic light emitting diodes based on m-MTDATA/BPhen exciplex

Abstract

High efficient yellow organic light emitting diodes (OLEDs) based on exciplex were reported. The exciplex was formed by 4, 4′, 4′′-tris [3-methylphenyl (phenyl) amino]-triphenylamine (m-MTDATA) and 4, 7-diphenyl-1, 10-phenanthroline (BPhen). The resulting yellow OLEDs exhibited an external quantum efficiency of over 7%, which is attributed to the effective energy back transfer from exciplex triplet state to exciplex singlet state. The maximum power efficiency of 25 lm/W was achieved. Doping a yellow phosphor Ir(bt)₂(acac) into m-MTDATA:BPhen blend, a high efficiency device was achieved with a turn-on voltage of 2.1 V, maximum power efficiency and external quantum efficiency of 86.1 lm/W and 20.7%, respectively.

Keywords

organic light-emitting diodes (OLEDs) / fluorescent / exciplex

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Acknowledgements

We sincerely thank Y. Gu, C. L. Yang and H. Xu for their careful testing of the samples. The authors gratefully acknowledge the National Natural Science Foundation of China (Grant Nos. 51333007 and 50973104), the National Basic Research Program of China (No. 2013CB834805), the Foundation of Jilin Research Council (Nos. 2012ZDGG001, 20130206003GX and 201105028), and Chinese Academy of Sciences Instrument Project (No. YZ201103) for the support of this research.

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg