Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (3LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex

Xiaofang Wei; Yanwei Liu; Taiping Hu; Zhiyi Li; Jianjun Liu; Ruifang Wang; Honglei Gao; Xiaoxiao Hu; Guanhao Liu; Pengfei Wang; Chun-sing Lee; Ying Wang

doi:10.3389/fchem.2019.00188

Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (³LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex

Xiaofang Wei, Yanwei Liu, Taiping Hu, Zhiyi Li, Jianjun Liu, Ruifang Wang, Honglei Gao, Xiaoxiao Hu, Guanhao Liu, Pengfei Wang, Chun-sing Lee, Ying Wang^*

^*Corresponding author for this work

Centre of Super-Diamond and Advanced Films

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

6 Citations (Scopus)

105 Downloads (CityUHK Scholars)

Abstract

A series of thermally activated delayed fluorescence (TADF) exciplex based on the TX-TerPy were constructed. The electronic coupling between the triplet local excited states (³LE) of the donors and acceptor and the charge transfer states had a great influence on the triplet exciton harvesting and Φ_PL. Herein, based on this strategy, three donor molecules TAPC, TCTA, and m-MTDATA were selected. The local triplet excited state (³LE) of the three donors are 2.93, 2.72 and 2.52 eV in pure films. And the ³LE of TX-TerPy is 2.69 eV in polystyrene film. The energy gap between the singlet charge transfer (¹CT) states of TAPC:TX-TerPy (7:1), TCTA:TX-TerPy (7:1) and the ³LE of TX-TerPy are 0.30 eV and 0.20 eV. Finally, the Φ_PL of TAPC:TX-TerPy (7:1) and TCTA:TX-TerPy (7:1) are 65.2 and 69.6%. When we changed the doping concentration of the exciplex from 15% to 50%, the ratio of the triplet decreased, and Φ_PL decreased by half, perhaps due to the increased energy gap between ¹CT and ³LE. Therefore, optimizing the ¹CT, ³CT, and ³LE facilitated the efficient exciplex TADF molecules.

Original language	English
Article number	188
Journal	Frontiers in Chemistry
Volume	7
Online published	9 Apr 2019
DOIs	https://doi.org/10.3389/fchem.2019.00188
Publication status	Published - Apr 2019

Research Keywords

Energy gap
Exciplex
Organic light emitting diode (OLED)
Pure thermally activated delayed fluorescence (TADF)
Thixanthone (TX) derivatives

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Wei, X., Liu, Y., Hu, T., Li, Z., Liu, J., Wang, R., Gao, H., Hu, X., Liu, G., Wang, P., Lee, C., & Wang, Y. (2019). Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (³LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex. Frontiers in Chemistry, 7, Article 188. https://doi.org/10.3389/fchem.2019.00188

@article{bbe86e3993504bf095b227039f157187,

title = "Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (3LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex",

abstract = "A series of thermally activated delayed fluorescence (TADF) exciplex based on the TX-TerPy were constructed. The electronic coupling between the triplet local excited states (3LE) of the donors and acceptor and the charge transfer states had a great influence on the triplet exciton harvesting and ΦPL. Herein, based on this strategy, three donor molecules TAPC, TCTA, and m-MTDATA were selected. The local triplet excited state (3LE) of the three donors are 2.93, 2.72 and 2.52 eV in pure films. And the 3LE of TX-TerPy is 2.69 eV in polystyrene film. The energy gap between the singlet charge transfer (1CT) states of TAPC:TX-TerPy (7:1), TCTA:TX-TerPy (7:1) and the 3LE of TX-TerPy are 0.30 eV and 0.20 eV. Finally, the ΦPL of TAPC:TX-TerPy (7:1) and TCTA:TX-TerPy (7:1) are 65.2 and 69.6%. When we changed the doping concentration of the exciplex from 15% to 50%, the ratio of the triplet decreased, and ΦPL decreased by half, perhaps due to the increased energy gap between 1CT and 3LE. Therefore, optimizing the 1CT, 3CT, and 3LE facilitated the efficient exciplex TADF molecules.",

keywords = "Energy gap, Exciplex, Organic light emitting diode (OLED), Pure thermally activated delayed fluorescence (TADF), Thixanthone (TX) derivatives",

author = "Xiaofang Wei and Yanwei Liu and Taiping Hu and Zhiyi Li and Jianjun Liu and Ruifang Wang and Honglei Gao and Xiaoxiao Hu and Guanhao Liu and Pengfei Wang and Chun-sing Lee and Ying Wang",

year = "2019",

month = apr,

doi = "10.3389/fchem.2019.00188",

language = "English",

volume = "7",

journal = "Frontiers in Chemistry",

issn = "2296-2646",

publisher = "Frontiers Media S.A.",

}

Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (³LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex. / Wei, Xiaofang; Liu, Yanwei; Hu, Taiping et al.
In: Frontiers in Chemistry, Vol. 7, 188, 04.2019.

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

TY - JOUR

T1 - Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet (3LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex

AU - Wei, Xiaofang

AU - Liu, Yanwei

AU - Hu, Taiping

AU - Li, Zhiyi

AU - Liu, Jianjun

AU - Wang, Ruifang

AU - Gao, Honglei

AU - Hu, Xiaoxiao

AU - Liu, Guanhao

AU - Wang, Pengfei

AU - Lee, Chun-sing

AU - Wang, Ying

PY - 2019/4

Y1 - 2019/4

N2 - A series of thermally activated delayed fluorescence (TADF) exciplex based on the TX-TerPy were constructed. The electronic coupling between the triplet local excited states (3LE) of the donors and acceptor and the charge transfer states had a great influence on the triplet exciton harvesting and ΦPL. Herein, based on this strategy, three donor molecules TAPC, TCTA, and m-MTDATA were selected. The local triplet excited state (3LE) of the three donors are 2.93, 2.72 and 2.52 eV in pure films. And the 3LE of TX-TerPy is 2.69 eV in polystyrene film. The energy gap between the singlet charge transfer (1CT) states of TAPC:TX-TerPy (7:1), TCTA:TX-TerPy (7:1) and the 3LE of TX-TerPy are 0.30 eV and 0.20 eV. Finally, the ΦPL of TAPC:TX-TerPy (7:1) and TCTA:TX-TerPy (7:1) are 65.2 and 69.6%. When we changed the doping concentration of the exciplex from 15% to 50%, the ratio of the triplet decreased, and ΦPL decreased by half, perhaps due to the increased energy gap between 1CT and 3LE. Therefore, optimizing the 1CT, 3CT, and 3LE facilitated the efficient exciplex TADF molecules.

AB - A series of thermally activated delayed fluorescence (TADF) exciplex based on the TX-TerPy were constructed. The electronic coupling between the triplet local excited states (3LE) of the donors and acceptor and the charge transfer states had a great influence on the triplet exciton harvesting and ΦPL. Herein, based on this strategy, three donor molecules TAPC, TCTA, and m-MTDATA were selected. The local triplet excited state (3LE) of the three donors are 2.93, 2.72 and 2.52 eV in pure films. And the 3LE of TX-TerPy is 2.69 eV in polystyrene film. The energy gap between the singlet charge transfer (1CT) states of TAPC:TX-TerPy (7:1), TCTA:TX-TerPy (7:1) and the 3LE of TX-TerPy are 0.30 eV and 0.20 eV. Finally, the ΦPL of TAPC:TX-TerPy (7:1) and TCTA:TX-TerPy (7:1) are 65.2 and 69.6%. When we changed the doping concentration of the exciplex from 15% to 50%, the ratio of the triplet decreased, and ΦPL decreased by half, perhaps due to the increased energy gap between 1CT and 3LE. Therefore, optimizing the 1CT, 3CT, and 3LE facilitated the efficient exciplex TADF molecules.

KW - Energy gap

KW - Exciplex

KW - Organic light emitting diode (OLED)

KW - Pure thermally activated delayed fluorescence (TADF)

KW - Thixanthone (TX) derivatives

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U2 - 10.3389/fchem.2019.00188

DO - 10.3389/fchem.2019.00188

M3 - RGC 21 - Publication in refereed journal

C2 - 31024884

SN - 2296-2646

VL - 7

JO - Frontiers in Chemistry

JF - Frontiers in Chemistry

M1 - 188

ER -