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High-efficiency, long-lifetime deep-blue organic light-emitting diodes

Nature Photonics volume 15, pages 208–215 (2021)Cite this article

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Abstract

Simultaneously achieving both a high efficiency and long lifetime in deep-blue organic light-emitting diodes is challenging. Here we report thermally activated delayed fluorescence (TADF) organic light-emitting diodes that aim to meet this goal by combining a new design of blue TADF materials with a triplet-exciton recycling protocol. Two TADF materials, one distributing and one emitting, were doped into a host to form triplet-exciton-distributed TADF devices. The singlet excitons were transferred from the host to the emitter via the distributing TADF material by cascade energy transfer, whereas the triplet excitons were transferred to the emitter as singlet excitons by a triplet-exciton recycling process between the low-triplet-energy host and the distributing TADF material. The resulting triplet-exciton-distributed TADF devices achieved a high external quantum efficiency of 33.5 ± 0.1, a colour coordinate corrected current efficiency over 400 cd A–1, a lifetime of >5,000 h and a y colour coordinate below 0.10.

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Fig. 1: Emission mechanism.
Fig. 2: Conventional TADF device performances.
Fig. 3: Data for the bottom-emitting devices.
Fig. 4: Device performance of the top-emitting devices.
Fig. 5: Optical characteristics.

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Acknowledgements

This material is based on work supported in the part by the Samsung Advanced Institute of Technology (SAIT). We thank S. Park for helpful discussions and support with the nuclear magnetic resonence spectrometer.

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Author notes

  1. These authors contributed equally: Soon Ok Jeon, Kyung Hyung Lee.

Authors and Affiliations

  1. Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Gyeonggi, Korea

    Soon Ok Jeon, Jong Soo Kim, Soo-Ghang Ihn, Yeon Sook Chung, Ji Whan Kim, Hasup Lee, Sunghan Kim & Hyeonho Choi

  2. School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi, Korea

    Kyung Hyung Lee & Jun Yeob Lee

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Contributions

S.O.J. and K.H.L. contributed equally to this work. H.L. performed the calculations. S.O.J. designed the molecules and assessed the synthetic feasibility of molecular candidates from the calculations. S.O.J. and Y.S.C. synthesized the compounds and analysed the spectroscopic data. K.H.L. fabricated and tested devices for bottom-emitting devices and characterized the electrical and optical properties of the thin films. J.S.K. performed the anisotropic horizontal orientation study. S.-G.I. and J.S.K. fabricated and characterized electrical and optical properties of the top-emitting devices. J.W.K. performed optical simulations and optimized the device structures for the top-emitting devices. S.O.J., K.H.L. and J.Y.L. wrote the first version of the manuscript. All authors contributed to the discussion, writing and editing of the manuscript. S.K. organized the project. H.C. supervised the computational chemistry study. J.Y.L. supervised the device fabrication and the project.

Corresponding authors

Correspondence to Soon Ok Jeon, Hyeonho Choi or Jun Yeob Lee.

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Competing interests

S.O.J., Y.S.C., H.L and S.-G.I. have filed a patent application (condensed cyclic compound and organic light-emitting device including the same; US patent application no. US 16/244,431; 10 January 2019). S.O.J, K.H.L, J.S.K, S.-G.I., Y.S.C, J.W.K, H.L, H.C and J.Y.L have submitted a patent application for this work, which was assigned to Samsung Electronics and Sungkyunkwan University.

Additional information

Peer review information Nature Photonics thanks Frederic Dumur, Lei Wang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Synthesis, Experimental, Methods for Device fabrication and measurements, Supplementary Figs. 1–15, Tables 1–6 and references.

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Jeon, S.O., Lee, K.H., Kim, J.S. et al. High-efficiency, long-lifetime deep-blue organic light-emitting diodes. Nat. Photonics 15, 208–215 (2021). https://doi.org/10.1038/s41566-021-00763-5

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