Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs

Hwan-Hee  Cho; Daniel G. Congrave; Alexander J. Gillett; Stephanie Montanaro; Haydn E. Francis; Victor Riesgo-Gonzalez; Junzhi Ye; Rituparno Chowdry; Weixuan Zeng; Marc K. Etherington; Jeroen Royakkers; Oliver Millington; Andrew D. Bond; Felix Plasser; Jarvist M. Frost; Clare P. Grey; Akshay Rao; Richard H. Friend; Neil C. Greenham; Hugo Bronstein

doi:10.1038/s41563-024-01812-4

Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs

Hwan-Hee Cho, Daniel G. Congrave^*, Alexander J. Gillett, Stephanie Montanaro, Haydn E. Francis, Victor Riesgo-Gonzalez, Junzhi Ye, Rituparno Chowdry, Weixuan Zeng, Marc K. Etherington, Jeroen Royakkers, Oliver Millington, Andrew D. Bond, Felix Plasser, Jarvist M. Frost, Clare P. Grey, Akshay Rao, Richard H. Friend, Neil C. Greenham^*, Hugo Bronstein^*

^*Corresponding author for this work

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

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Abstract

Hyperfluorescence shows great promise for the next generation of
commercially feasible blue organic light-emitting diodes, for which
eliminating the Dexter transfer to terminal emitter triplet states is key to
efficiency and stability. Current devices rely on high-gap matrices to prevent
Dexter transfer, which unfortunately leads to overly complex devices from
a fabrication standpoint. Here we introduce a molecular design where
ultranarrowband blue emitters are covalently encapsulated by insulating
alkylene straps. Organic light-emitting diodes with simple emissive layers
consisting of pristine thermally activated delayed fluorescence hosts doped
with encapsulated terminal emitters exhibit negligible external quantum
efficiency drops compared with non-doped devices, enabling a maximum
external quantum efficiency of 21.5%. To explain the high efficiency in the
absence of high-gap matrices, we turn to transient absorption spectroscopy.
It is directly observed that Dexter transfer from a pristine thermally
activated delayed fluorescence sensitizer host can be substantially reduced
by an encapsulated terminal emitter, opening the door to highly efficient
‘matrix-free’ blue hyperfluorescence.

Original language	English
Pages (from-to)	519-526
Number of pages	17
Journal	Nature Materials
Volume	23
Issue number	4
Early online date	13 Mar 2024
DOIs	https://doi.org/10.1038/s41563-024-01812-4
Publication status	Published - Apr 2024

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Cho, H.-H., Congrave, D. G., Gillett, A. J., Montanaro, S., Francis, H. E., Riesgo-Gonzalez, V., Ye, J., Chowdry, R., Zeng, W., Etherington, M. K., Royakkers, J., Millington, O., Bond, A. D., Plasser, F., Frost, J. M., Grey, C. P., Rao, A., Friend, R. H., Greenham, N. C., & Bronstein, H. (2024). Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs. Nature Materials, 23(4), 519-526. https://doi.org/10.1038/s41563-024-01812-4

@article{f207c0170b1f4471b9ce3ec26c9622bc,

title = "Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs",

abstract = "Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, for which eliminating the Dexter transfer to terminal emitter triplet states is key to efficiency and stability. Current devices rely on high-gap matrices to prevent Dexter transfer, which unfortunately leads to overly complex devices from a fabrication standpoint. Here we introduce a molecular design where ultranarrowband blue emitters are covalently encapsulated by insulating alkylene straps. Organic light-emitting diodes with simple emissive layers consisting of pristine thermally activated delayed fluorescence hosts doped with encapsulated terminal emitters exhibit negligible external quantum efficiency drops compared with non-doped devices, enabling a maximum external quantum efficiency of 21.5\%. To explain the high efficiency in the absence of high-gap matrices, we turn to transient absorption spectroscopy. It is directly observed that Dexter transfer from a pristine thermally activated delayed fluorescence sensitizer host can be substantially reduced by an encapsulated terminal emitter, opening the door to highly efficient {\textquoteleft}matrix-free{\textquoteright} blue hyperfluorescence.",

author = "Hwan-Hee Cho and Congrave, \{Daniel G.\} and Gillett, \{Alexander J.\} and Stephanie Montanaro and Francis, \{Haydn E.\} and Victor Riesgo-Gonzalez and Junzhi Ye and Rituparno Chowdry and Weixuan Zeng and Etherington, \{Marc K.\} and Jeroen Royakkers and Oliver Millington and Bond, \{Andrew D.\} and Felix Plasser and Frost, \{Jarvist M.\} and Grey, \{Clare P.\} and Akshay Rao and Friend, \{Richard H.\} and Greenham, \{Neil C.\} and Hugo Bronstein",

year = "2024",

month = apr,

doi = "10.1038/s41563-024-01812-4",

language = "English",

volume = "23",

pages = "519--526",

journal = "Nature Materials",

issn = "1476-1122",

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Cho, H-H, Congrave, DG, Gillett, AJ, Montanaro, S, Francis, HE, Riesgo-Gonzalez, V, Ye, J, Chowdry, R, Zeng, W, Etherington, MK, Royakkers, J, Millington, O, Bond, AD, Plasser, F, Frost, JM, Grey, CP, Rao, A, Friend, RH, Greenham, NC & Bronstein, H 2024, 'Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs', Nature Materials, vol. 23, no. 4, pp. 519-526. https://doi.org/10.1038/s41563-024-01812-4

TY - JOUR

T1 - Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs

AU - Cho, Hwan-Hee

AU - Congrave, Daniel G.

AU - Gillett, Alexander J.

AU - Montanaro, Stephanie

AU - Francis, Haydn E.

AU - Riesgo-Gonzalez, Victor

AU - Ye, Junzhi

AU - Chowdry, Rituparno

AU - Zeng, Weixuan

AU - Etherington, Marc K.

AU - Royakkers, Jeroen

AU - Millington, Oliver

AU - Bond, Andrew D.

AU - Plasser, Felix

AU - Frost, Jarvist M.

AU - Grey, Clare P.

AU - Rao, Akshay

AU - Friend, Richard H.

AU - Greenham, Neil C.

AU - Bronstein, Hugo

PY - 2024/4

Y1 - 2024/4

N2 - Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, for which eliminating the Dexter transfer to terminal emitter triplet states is key to efficiency and stability. Current devices rely on high-gap matrices to prevent Dexter transfer, which unfortunately leads to overly complex devices from a fabrication standpoint. Here we introduce a molecular design where ultranarrowband blue emitters are covalently encapsulated by insulating alkylene straps. Organic light-emitting diodes with simple emissive layers consisting of pristine thermally activated delayed fluorescence hosts doped with encapsulated terminal emitters exhibit negligible external quantum efficiency drops compared with non-doped devices, enabling a maximum external quantum efficiency of 21.5%. To explain the high efficiency in the absence of high-gap matrices, we turn to transient absorption spectroscopy. It is directly observed that Dexter transfer from a pristine thermally activated delayed fluorescence sensitizer host can be substantially reduced by an encapsulated terminal emitter, opening the door to highly efficient ‘matrix-free’ blue hyperfluorescence.

AB - Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, for which eliminating the Dexter transfer to terminal emitter triplet states is key to efficiency and stability. Current devices rely on high-gap matrices to prevent Dexter transfer, which unfortunately leads to overly complex devices from a fabrication standpoint. Here we introduce a molecular design where ultranarrowband blue emitters are covalently encapsulated by insulating alkylene straps. Organic light-emitting diodes with simple emissive layers consisting of pristine thermally activated delayed fluorescence hosts doped with encapsulated terminal emitters exhibit negligible external quantum efficiency drops compared with non-doped devices, enabling a maximum external quantum efficiency of 21.5%. To explain the high efficiency in the absence of high-gap matrices, we turn to transient absorption spectroscopy. It is directly observed that Dexter transfer from a pristine thermally activated delayed fluorescence sensitizer host can be substantially reduced by an encapsulated terminal emitter, opening the door to highly efficient ‘matrix-free’ blue hyperfluorescence.

UR - https://www.scopus.com/pages/publications/85187691852

U2 - 10.1038/s41563-024-01812-4

DO - 10.1038/s41563-024-01812-4

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SN - 1476-1122

VL - 23

SP - 519

EP - 526

JO - Nature Materials

JF - Nature Materials

IS - 4

ER -

Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs

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