Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states

Lin Song Cui; Alexander J. Gillett; Shou Feng Zhang; Hao Ye; Yuan Liu; Xian Kai Chen; Ze Sen Lin; Emrys W. Evans; William K. Myers; Tanya K. Ronson; Hajime Nakanotani; Sebastian Reineke; Jean Luc Bredas; Chihaya Adachi; Richard H. Friend

doi:10.1038/s41566-020-0668-z

Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states

Lin Song Cui, Alexander J. Gillett, Shou Feng Zhang, Hao Ye, Yuan Liu, Xian Kai Chen, Ze Sen Lin, Emrys W. Evans, William K. Myers, Tanya K. Ronson, Hajime Nakanotani, Sebastian Reineke, Jean Luc Bredas, Chihaya Adachi, Richard H. Friend

Applied Chemistry

Research output: Contribution to journal › Article › peer-review

277 Citations (Scopus)

Abstract

A spin-flip from a triplet to a singlet excited state, that is, reverse intersystem crossing (RISC), is an attractive route for improving light emission in organic light-emitting diodes, as shown by devices using thermally activated delayed fluorescence (TADF). However, device stability and efficiency roll-off remain challenging issues that originate from a slow RISC rate (k_RISC). Here, we report a TADF molecule with multiple donor units that form charge-resonance-type hybrid triplet states leading to a small singlet–triplet energy splitting, large spin–orbit couplings, and a dense manifold of triplet states energetically close to the singlets. The k_RISC in our TADF molecule is as fast as 1.5 × 10⁷ s⁻¹, a value some two orders of magnitude higher than typical TADF emitters. Organic light-emitting diodes based on this molecule exhibit good stability (estimated T₉₀ about 600 h for 1,000 cd m⁻²), high maximum external quantum efficiency ('29.3%) and low efficiency roll-off ('2.3% at 1,000 cd m⁻²).

Original language	English
Pages (from-to)	636-642
Number of pages	7
Journal	Nature Photonics
Volume	14
Issue number	10
DOIs	https://doi.org/10.1038/s41566-020-0668-z
Publication status	Published - Oct 1 2020

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Atomic and Molecular Physics, and Optics

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Cui, L. S., Gillett, A. J., Zhang, S. F., Ye, H., Liu, Y., Chen, X. K., Lin, Z. S., Evans, E. W., Myers, W. K., Ronson, T. K., Nakanotani, H., Reineke, S., Bredas, J. L., Adachi, C., & Friend, R. H. (2020). Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states. Nature Photonics, 14(10), 636-642. https://doi.org/10.1038/s41566-020-0668-z

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title = "Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states",

abstract = "A spin-flip from a triplet to a singlet excited state, that is, reverse intersystem crossing (RISC), is an attractive route for improving light emission in organic light-emitting diodes, as shown by devices using thermally activated delayed fluorescence (TADF). However, device stability and efficiency roll-off remain challenging issues that originate from a slow RISC rate (kRISC). Here, we report a TADF molecule with multiple donor units that form charge-resonance-type hybrid triplet states leading to a small singlet–triplet energy splitting, large spin–orbit couplings, and a dense manifold of triplet states energetically close to the singlets. The kRISC in our TADF molecule is as fast as 1.5 × 107 s−1, a value some two orders of magnitude higher than typical TADF emitters. Organic light-emitting diodes based on this molecule exhibit good stability (estimated T90 about 600 h for 1,000 cd m−2), high maximum external quantum efficiency ('29.3%) and low efficiency roll-off ('2.3% at 1,000 cd m−2).",

author = "Cui, {Lin Song} and Gillett, {Alexander J.} and Zhang, {Shou Feng} and Hao Ye and Yuan Liu and Chen, {Xian Kai} and Lin, {Ze Sen} and Evans, {Emrys W.} and Myers, {William K.} and Ronson, {Tanya K.} and Hajime Nakanotani and Sebastian Reineke and Bredas, {Jean Luc} and Chihaya Adachi and Friend, {Richard H.}",

note = "Funding Information: is Senior Researcher (Department of Philosophy i , University of Granada). He has contributed with several papers to the fields of the philosophy of language and history of analytic philosophy. His research is mainly focused on the analysis of propositional attitude ascriptions, context-dependence, evaluative meaning, and expressivism. He currently co-directs the research project “Contemporary Expressivisms and the indispensability of the normative vocabulary”, funded by the Spanish Ministry of Economy and Competitiveness. Funding Information: The work on this paper was financially supported by the grant National Science Centre. Poland, 2012/05/B/HS1/01711(Anna W{\'o}jtowicz). Funding Information: Work for this paper was funded by the research project “Naturalism, expressivism and normativity” ( mineco , Spain). Thanks to Manuel Heras-Escribano, Marek Hetma{\'n}ski and two anonymous referees for insightful comments and suggestions. Publisher Copyright: {\textcopyright} 2020, The Author(s), under exclusive licence to Springer Nature Limited.",

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doi = "10.1038/s41566-020-0668-z",

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T1 - Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states

AU - Cui, Lin Song

AU - Gillett, Alexander J.

AU - Zhang, Shou Feng

AU - Ye, Hao

AU - Liu, Yuan

AU - Chen, Xian Kai

AU - Lin, Ze Sen

AU - Evans, Emrys W.

AU - Myers, William K.

AU - Ronson, Tanya K.

AU - Nakanotani, Hajime

AU - Reineke, Sebastian

AU - Bredas, Jean Luc

AU - Adachi, Chihaya

AU - Friend, Richard H.

N1 - Funding Information: is Senior Researcher (Department of Philosophy i , University of Granada). He has contributed with several papers to the fields of the philosophy of language and history of analytic philosophy. His research is mainly focused on the analysis of propositional attitude ascriptions, context-dependence, evaluative meaning, and expressivism. He currently co-directs the research project “Contemporary Expressivisms and the indispensability of the normative vocabulary”, funded by the Spanish Ministry of Economy and Competitiveness. Funding Information: The work on this paper was financially supported by the grant National Science Centre. Poland, 2012/05/B/HS1/01711(Anna Wójtowicz). Funding Information: Work for this paper was funded by the research project “Naturalism, expressivism and normativity” ( mineco , Spain). Thanks to Manuel Heras-Escribano, Marek Hetmański and two anonymous referees for insightful comments and suggestions. Publisher Copyright: © 2020, The Author(s), under exclusive licence to Springer Nature Limited.

PY - 2020/10/1

Y1 - 2020/10/1

N2 - A spin-flip from a triplet to a singlet excited state, that is, reverse intersystem crossing (RISC), is an attractive route for improving light emission in organic light-emitting diodes, as shown by devices using thermally activated delayed fluorescence (TADF). However, device stability and efficiency roll-off remain challenging issues that originate from a slow RISC rate (kRISC). Here, we report a TADF molecule with multiple donor units that form charge-resonance-type hybrid triplet states leading to a small singlet–triplet energy splitting, large spin–orbit couplings, and a dense manifold of triplet states energetically close to the singlets. The kRISC in our TADF molecule is as fast as 1.5 × 107 s−1, a value some two orders of magnitude higher than typical TADF emitters. Organic light-emitting diodes based on this molecule exhibit good stability (estimated T90 about 600 h for 1,000 cd m−2), high maximum external quantum efficiency ('29.3%) and low efficiency roll-off ('2.3% at 1,000 cd m−2).

AB - A spin-flip from a triplet to a singlet excited state, that is, reverse intersystem crossing (RISC), is an attractive route for improving light emission in organic light-emitting diodes, as shown by devices using thermally activated delayed fluorescence (TADF). However, device stability and efficiency roll-off remain challenging issues that originate from a slow RISC rate (kRISC). Here, we report a TADF molecule with multiple donor units that form charge-resonance-type hybrid triplet states leading to a small singlet–triplet energy splitting, large spin–orbit couplings, and a dense manifold of triplet states energetically close to the singlets. The kRISC in our TADF molecule is as fast as 1.5 × 107 s−1, a value some two orders of magnitude higher than typical TADF emitters. Organic light-emitting diodes based on this molecule exhibit good stability (estimated T90 about 600 h for 1,000 cd m−2), high maximum external quantum efficiency ('29.3%) and low efficiency roll-off ('2.3% at 1,000 cd m−2).

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JO - Nature Photonics

JF - Nature Photonics

IS - 10

ER -

Fast spin-flip enables efficient and stable organic electroluminescence from charge-transfer states

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