Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane

Yan Xu; Dongyang Chen; Sen Wu; Dominic J.  Black; Hui  Wang; Robert  Pal; Xiaohong  Zhang; Eli Zysman-Colman

doi:10.31635/ccschem.025.202505963

Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane

Yan Xu, Dongyang Chen, Sen Wu, Dominic J. Black, Hui Wang, Robert Pal^*, Xiaohong Zhang^*, Eli Zysman-Colman^*

^*Corresponding author for this work

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

Abstract

The development of circularly polarized multiresonant thermally activated delayed fluorescence materials with fast reverse intersystem crossing (RISC) process remains a challenge. Herein, we introduce high-lying excited states to assist the RISC process. Through arranging two known MR-TADF emitters t CzBN and DiKTa at the pseudo-ortho position of a chiral skeleton paracyclophane (PCP), the excited-state density was increased. The proof-of-concept emitter po -PCP- t CzBN-DiKTa shows nearly three times higher k_RISC (5.31 × 10⁴ s⁻¹) than PCP- t CzBN (1.73 × 10⁴ s⁻¹) without compromising color purity and exhibiting circularly polarized luminescence with |g_PL| values at the 10⁻⁴ level. The solution-processed organic light-emitting diodes with po -PCP- t CzBN-DiKTa show high maximum external quantum efficiency (EQE_max) reaching 23% with a moderate efficiency roll-off, showing EQE of 18% and 9% at 100 and 1000 cd/m².

Original language	English
Number of pages	15
Journal	CCS Chemistry
Volume	Ahead of Print
Early online date	20 Sept 2025
DOIs	https://doi.org/10.31635/ccschem.025.202505963
Publication status	E-pub ahead of print - 20 Sept 2025

Keywords

Multiresonant thermally activated delayed fluorescence
Circularly polarized luminescence
[2,2]paracyclophane
Solution-processed organic light-emitting diodes

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10.31635/ccschem.025.202505963Licence: CC BY-NC

Xu_2025_CCSC_Accelerating-reverse-intersystem-crossing-TADF-emitters_CC
© 2025 Chinese Chemical Society. Published under the terms of the Creative Commons Attribution–NonCommercial 3.0 Unported license (CC BY-NC 3.0) (https://creativecommons.org/licenses/by-nc/3.0/). This license allows remixing, tweaking, and building upon the article noncommercially, as long as attribution to the original CCS Chemistry publication is included.
Final published version, 3.23 MBLicence: CC BY-NC

1 Finished
2 Active

Allan Watson Programme Grant: Boron: Beyond the Reagent
Watson, A. (PI), Morris, R. (CoI), Smith, A. (CoI) & Zysman-Colman, E. (CoI)
UK Research and Innovation
1/05/23 → 30/04/28
Project: Standard
TADF Solutions: TADF SOLUTIONS: addressing the challenges of high-performance solution-processed OLEDs using sustainable materials
Zysman-Colman, E. (PI)
UKRI (EU)
1/10/22 → 30/09/26
Project: Standard
MR TADF: Multi-resonance TADF materials for highly efficient and stable OLEDs
Zysman-Colman, E. (PI)
EPSRC
1/07/22 → 30/06/25
Project: Standard

Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane (dataset)
Xu, Y. (Creator), Chen, D. (Creator), Wu, S. (Creator), Black, D. J. (Creator), Wang, H. (Creator), Pal, R. (Creator), Zhang, X. (Creator) & Zysman-Colman, E. (Creator), University of St Andrews, 23 Sept 2025
DOI: 10.17630/a1074251-7529-4cf0-b827-6747d699ffe2
Dataset

File

Design and synthesis of chiral thermally activated delayed fluorescence emitters for organic light emitting diodes
Xu, Y. (Author), Zysman-Colman, E. (Supervisor), 3 Dec 2025
Student thesis: Doctoral Thesis (PhD)

Cite this

@article{0c3309b257d640ac82f93c649bb3b20c,

title = "Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane",

abstract = "The development of circularly polarized multiresonant thermally activated delayed fluorescence materials with fast reverse intersystem crossing (RISC) process remains a challenge. Herein, we introduce high-lying excited states to assist the RISC process. Through arranging two known MR-TADF emitters t CzBN and DiKTa at the pseudo-ortho position of a chiral skeleton paracyclophane (PCP), the excited-state density was increased. The proof-of-concept emitter po -PCP- t CzBN-DiKTa shows nearly three times higher kRISC (5.31 × 104 s−1) than PCP- t CzBN (1.73 × 104 s−1) without compromising color purity and exhibiting circularly polarized luminescence with |gPL| values at the 10−4 level. The solution-processed organic light-emitting diodes with po -PCP- t CzBN-DiKTa show high maximum external quantum efficiency (EQEmax) reaching 23\% with a moderate efficiency roll-off, showing EQE of 18\% and 9\% at 100 and 1000 cd/m2.",

keywords = "Multiresonant thermally activated delayed fluorescence, Circularly polarized luminescence, [2,2]paracyclophane, Solution-processed organic light-emitting diodes",

author = "Yan Xu and Dongyang Chen and Sen Wu and Black, \{Dominic J.\} and Hui Wang and Robert Pal and Xiaohong Zhang and Eli Zysman-Colman",

note = "Funding: Y. X. acknowledges the China Scholarship Council (202106310038) for support. D.Chen acknowledges the support from the China Postdoctoral Science Foundation(2022TQ0227) and the Natural Science Foundation of Jiangsu Province, China(BK20230508). S. W. acknowledges the China Scholarship Council (201906250199).X. Z. acknowledges support from the National Natural Science Foundation of China(Grant No. 52130304) the Suzhou Key Laboratory of Functional Nano \& Soft Materials,the Collaborative Innovation Center of Suzhou Nano Science \& Technology, the 111Project. E.Z-.C. acknowledges support from the Engineering and Physical SciencesResearch Council (EPSRC; EP/W015137/1, EP/W007517/1, and EP/Z535291/1). Thisproject has been partly funded by the European Union Horizon 2021 research andinnovation programme under grant agreement No. 101073045 (TADFsolutions) andthe EPSRC grant EP/X026175/1. RP and DJB acknowledge support from BBSRCBB/S017615/1, BB/X001172/1 and EPSRC EP/X040259/1.",

year = "2025",

month = sep,

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doi = "10.31635/ccschem.025.202505963",

language = "English",

volume = "Ahead of Print",

journal = "CCS Chemistry",

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publisher = "Chinese Chemical Society",

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TY - JOUR

T1 - Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane

AU - Xu, Yan

AU - Chen, Dongyang

AU - Wu, Sen

AU - Black, Dominic J.

AU - Wang, Hui

AU - Pal, Robert

AU - Zhang, Xiaohong

AU - Zysman-Colman, Eli

N1 - Funding: Y. X. acknowledges the China Scholarship Council (202106310038) for support. D.Chen acknowledges the support from the China Postdoctoral Science Foundation(2022TQ0227) and the Natural Science Foundation of Jiangsu Province, China(BK20230508). S. W. acknowledges the China Scholarship Council (201906250199).X. Z. acknowledges support from the National Natural Science Foundation of China(Grant No. 52130304) the Suzhou Key Laboratory of Functional Nano & Soft Materials,the Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111Project. E.Z-.C. acknowledges support from the Engineering and Physical SciencesResearch Council (EPSRC; EP/W015137/1, EP/W007517/1, and EP/Z535291/1). Thisproject has been partly funded by the European Union Horizon 2021 research andinnovation programme under grant agreement No. 101073045 (TADFsolutions) andthe EPSRC grant EP/X026175/1. RP and DJB acknowledge support from BBSRCBB/S017615/1, BB/X001172/1 and EPSRC EP/X040259/1.

PY - 2025/9/20

Y1 - 2025/9/20

N2 - The development of circularly polarized multiresonant thermally activated delayed fluorescence materials with fast reverse intersystem crossing (RISC) process remains a challenge. Herein, we introduce high-lying excited states to assist the RISC process. Through arranging two known MR-TADF emitters t CzBN and DiKTa at the pseudo-ortho position of a chiral skeleton paracyclophane (PCP), the excited-state density was increased. The proof-of-concept emitter po -PCP- t CzBN-DiKTa shows nearly three times higher kRISC (5.31 × 104 s−1) than PCP- t CzBN (1.73 × 104 s−1) without compromising color purity and exhibiting circularly polarized luminescence with |gPL| values at the 10−4 level. The solution-processed organic light-emitting diodes with po -PCP- t CzBN-DiKTa show high maximum external quantum efficiency (EQEmax) reaching 23% with a moderate efficiency roll-off, showing EQE of 18% and 9% at 100 and 1000 cd/m2.

AB - The development of circularly polarized multiresonant thermally activated delayed fluorescence materials with fast reverse intersystem crossing (RISC) process remains a challenge. Herein, we introduce high-lying excited states to assist the RISC process. Through arranging two known MR-TADF emitters t CzBN and DiKTa at the pseudo-ortho position of a chiral skeleton paracyclophane (PCP), the excited-state density was increased. The proof-of-concept emitter po -PCP- t CzBN-DiKTa shows nearly three times higher kRISC (5.31 × 104 s−1) than PCP- t CzBN (1.73 × 104 s−1) without compromising color purity and exhibiting circularly polarized luminescence with |gPL| values at the 10−4 level. The solution-processed organic light-emitting diodes with po -PCP- t CzBN-DiKTa show high maximum external quantum efficiency (EQEmax) reaching 23% with a moderate efficiency roll-off, showing EQE of 18% and 9% at 100 and 1000 cd/m2.

KW - Multiresonant thermally activated delayed fluorescence

KW - Circularly polarized luminescence

KW - [2,2]paracyclophane

KW - Solution-processed organic light-emitting diodes

U2 - 10.31635/ccschem.025.202505963

DO - 10.31635/ccschem.025.202505963

M3 - Article

SN - 2096-5745

VL - Ahead of Print

JO - CCS Chemistry

JF - CCS Chemistry

ER -

Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane

Abstract

Keywords

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Projects

Allan Watson Programme Grant: Boron: Beyond the Reagent

TADF Solutions: TADF SOLUTIONS: addressing the challenges of high-performance solution-processed OLEDs using sustainable materials

MR TADF: Multi-resonance TADF materials for highly efficient and stable OLEDs

Datasets

Accelerating reverse intersystem crossing by bridging two multiresonant thermally activated delayed fluorescence emitters with [2.2]paracyclophane (dataset)

Student theses

Design and synthesis of chiral thermally activated delayed fluorescence emitters for organic light emitting diodes

Cite this