Molecular engineering on all ortho-linked carbazole/oxadiazole hybrids toward highly-efficient thermally activated delayed fluorescence materials in OLEDs

Wenbo Yuan; Hannan Yang; Mucan Zhang; Die Hu; Shigang Wan; Zijing Li; Changsheng Shi; Ning Sun; Youtian Tao; Wei Huang

doi:10.1016/j.cclet.2019.08.019

Molecular engineering on all ortho-linked carbazole/oxadiazole hybrids toward highly-efficient thermally activated delayed fluorescence materials in OLEDs

Wenbo Yuan, Hannan Yang, Mucan Zhang, Die Hu, Shigang Wan, Zijing Li, Changsheng Shi, Ning Sun, Youtian Tao, Wei Huang

SCHOOL OF FLEXIBLE ELECTRONICS(FUTURE TECHNOLOGIES)|INSTITUTE OF ADVANCED MATERIALS(IAM)

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

27 Scopus citations

Abstract

The highest efficiency thermally activated delayed fluorescence (TADF) emitters in OLEDs are mostly based on twisted donor/acceptor (D/A) type organic molecules. Herein, we report the rational molecular design on twisted all ortho-linked carbazole/oxadiazole (Cz/OXD) hybrids with tunable D-A interactions by adjusting the numbers of donor/acceptor units and electron-donating abilities. Singlet-triplet energy bandgaps (ΔE_ST) are facilely tuned from ∼0.4, 0.15 to ∼0 eV in D-A, D-A-D to A-D-A type compounds. This variation correlates well with triplet-excited-state frontier orbital spatial separation efficiency. Non-TADF feature with solid state photoluminescence quantum yield (PLQY) < 10% is observed in D-A type 2CzOXD and D-A-D type 4CzOXD. Owing to the extremely low ΔE_ST for efficient reverse intersystem crossing, strong TADF with PLQY of 71%–92% is achieved in A-D-A type 4CzDOXD and 4tCzDOXD. High external quantum efficiency from 19.4% to 22.6% is achieved in A-D-A typed 4CzDOXD and 4tCzDOXD.

Original language	English
Pages (from-to)	1955-1958
Number of pages	4
Journal	Chinese Chemical Letters
Volume	30
Issue number	11
DOIs	https://doi.org/10.1016/j.cclet.2019.08.019
State	Published - Nov 2019

Keywords

Carbazole
Donor-acceptor
Organic light-emitting diodes
Oxadiazole
Thermally activated delayed fluorescence

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10.1016/j.cclet.2019.08.019

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title = "Molecular engineering on all ortho-linked carbazole/oxadiazole hybrids toward highly-efficient thermally activated delayed fluorescence materials in OLEDs",

abstract = "The highest efficiency thermally activated delayed fluorescence (TADF) emitters in OLEDs are mostly based on twisted donor/acceptor (D/A) type organic molecules. Herein, we report the rational molecular design on twisted all ortho-linked carbazole/oxadiazole (Cz/OXD) hybrids with tunable D-A interactions by adjusting the numbers of donor/acceptor units and electron-donating abilities. Singlet-triplet energy bandgaps (ΔEST) are facilely tuned from ∼0.4, 0.15 to ∼0 eV in D-A, D-A-D to A-D-A type compounds. This variation correlates well with triplet-excited-state frontier orbital spatial separation efficiency. Non-TADF feature with solid state photoluminescence quantum yield (PLQY) < 10% is observed in D-A type 2CzOXD and D-A-D type 4CzOXD. Owing to the extremely low ΔEST for efficient reverse intersystem crossing, strong TADF with PLQY of 71%–92% is achieved in A-D-A type 4CzDOXD and 4tCzDOXD. High external quantum efficiency from 19.4% to 22.6% is achieved in A-D-A typed 4CzDOXD and 4tCzDOXD.",

keywords = "Carbazole, Donor-acceptor, Organic light-emitting diodes, Oxadiazole, Thermally activated delayed fluorescence",

author = "Wenbo Yuan and Hannan Yang and Mucan Zhang and Die Hu and Shigang Wan and Zijing Li and Changsheng Shi and Ning Sun and Youtian Tao and Wei Huang",

note = "Publisher Copyright: {\textcopyright} 2019",

year = "2019",

month = nov,

doi = "10.1016/j.cclet.2019.08.019",

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T1 - Molecular engineering on all ortho-linked carbazole/oxadiazole hybrids toward highly-efficient thermally activated delayed fluorescence materials in OLEDs

AU - Yuan, Wenbo

AU - Yang, Hannan

AU - Zhang, Mucan

AU - Hu, Die

AU - Wan, Shigang

AU - Li, Zijing

AU - Shi, Changsheng

AU - Sun, Ning

AU - Tao, Youtian

AU - Huang, Wei

PY - 2019/11

Y1 - 2019/11

N2 - The highest efficiency thermally activated delayed fluorescence (TADF) emitters in OLEDs are mostly based on twisted donor/acceptor (D/A) type organic molecules. Herein, we report the rational molecular design on twisted all ortho-linked carbazole/oxadiazole (Cz/OXD) hybrids with tunable D-A interactions by adjusting the numbers of donor/acceptor units and electron-donating abilities. Singlet-triplet energy bandgaps (ΔEST) are facilely tuned from ∼0.4, 0.15 to ∼0 eV in D-A, D-A-D to A-D-A type compounds. This variation correlates well with triplet-excited-state frontier orbital spatial separation efficiency. Non-TADF feature with solid state photoluminescence quantum yield (PLQY) < 10% is observed in D-A type 2CzOXD and D-A-D type 4CzOXD. Owing to the extremely low ΔEST for efficient reverse intersystem crossing, strong TADF with PLQY of 71%–92% is achieved in A-D-A type 4CzDOXD and 4tCzDOXD. High external quantum efficiency from 19.4% to 22.6% is achieved in A-D-A typed 4CzDOXD and 4tCzDOXD.

AB - The highest efficiency thermally activated delayed fluorescence (TADF) emitters in OLEDs are mostly based on twisted donor/acceptor (D/A) type organic molecules. Herein, we report the rational molecular design on twisted all ortho-linked carbazole/oxadiazole (Cz/OXD) hybrids with tunable D-A interactions by adjusting the numbers of donor/acceptor units and electron-donating abilities. Singlet-triplet energy bandgaps (ΔEST) are facilely tuned from ∼0.4, 0.15 to ∼0 eV in D-A, D-A-D to A-D-A type compounds. This variation correlates well with triplet-excited-state frontier orbital spatial separation efficiency. Non-TADF feature with solid state photoluminescence quantum yield (PLQY) < 10% is observed in D-A type 2CzOXD and D-A-D type 4CzOXD. Owing to the extremely low ΔEST for efficient reverse intersystem crossing, strong TADF with PLQY of 71%–92% is achieved in A-D-A type 4CzDOXD and 4tCzDOXD. High external quantum efficiency from 19.4% to 22.6% is achieved in A-D-A typed 4CzDOXD and 4tCzDOXD.

KW - Carbazole

KW - Donor-acceptor

KW - Organic light-emitting diodes

KW - Oxadiazole

KW - Thermally activated delayed fluorescence

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M3 - 文章

AN - SCOPUS:85071989995

SN - 1001-8417

VL - 30

SP - 1955

EP - 1958

JO - Chinese Chemical Letters

JF - Chinese Chemical Letters

IS - 11

ER -

Molecular engineering on all ortho-linked carbazole/oxadiazole hybrids toward highly-efficient thermally activated delayed fluorescence materials in OLEDs

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Keywords

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