Intramolecular Exciplex-Typed Molecule Based on A Stereoscopic V-Shaped Aromatic Macrocycle and Investigation of Host-Dependence of Exciton Utilization

26 Pages Posted: 18 May 2022

See all articles by Jun Ye

Jun Ye

Ningbo University

De-Yan Qin

Ningbo University

Ming Zhang

affiliation not provided to SSRN

Ya-Nan Hu

Soochow University

Yi-Xin Miao

Ningbo University

Cai-Jun Zheng

affiliation not provided to SSRN

Jing Zhang

Ningbo University

Wei Xu

Ningbo University

Jia-Cheng Li

Ningbo University

Kai Wang

Soochow University

Xiao-Hong Zhang

Soochow University

Abstract

Through-space charge transfer (TSCT) has been increasingly utilized for the design of efficient thermally activated delayed fluorescence (TADF) emitters. TSCT molecular skeletons with spatially and electronically confined D/A subunits can provide a small ΔE ST , and also ease for fine control of CT properties within a single molecule. However so far TSCT-TADF molecules have not been fully investigated. Herein, we report a new ortho -position molecular pattern for TSCT-TADF design, using a stereoscopic V-shaped aromatic macrocycle of electron-deficient oxacalix[2]arene[2]triazine to “clip” the electron-rich triphenylamine unit. The new emitter OC2A2T-TPA exhibits a small ΔE ST of 18 meV, and the OLED device that uses high-energy-level host DPEPO realizes the first-time electroluminescence application of OC2A2T-type macrocyclic compounds by achieving an impressive external quantum efficiency (EQE) of 14.6%. Further host-dependence investigation reveals that OC2A2T-TPA actually behaves like an intramolecular exciplex, exhibiting high exciton utilization once its high-lying locally excited (LE) states on D/A could be sensitized first in the case of DPEPO host, otherwise low exciton utilization in the case of lower-energy-level mCP host. This work opens a way to enrich TSCT-TADF design and clarifies the importance to involve the high-lying LE states in the energy transfer routes for high-efficiency intramolecular-exciplex molecules.

Keywords: through-space charge transfer, Thermally Activated Delayed Fluorescence, aromatic macrocycle, locally excited states, oxacalix[2]arene[2]triazine

Suggested Citation

Ye, Jun and Qin, De-Yan and Zhang, Ming and Hu, Ya-Nan and Miao, Yi-Xin and Zheng, Cai-Jun and Zhang, Jing and Xu, Wei and Li, Jia-Cheng and Wang, Kai and Zhang, Xiao-Hong, Intramolecular Exciplex-Typed Molecule Based on A Stereoscopic V-Shaped Aromatic Macrocycle and Investigation of Host-Dependence of Exciton Utilization. Available at SSRN: https://ssrn.com/abstract=4112736 or http://dx.doi.org/10.2139/ssrn.4112736

Jun Ye (Contact Author)

Ningbo University ( email )

China

De-Yan Qin

Ningbo University ( email )

China

Ming Zhang

affiliation not provided to SSRN ( email )

No Address Available

Ya-Nan Hu

Soochow University ( email )

No. 1 Shizi Street
Taipei, 215006
Taiwan

Yi-Xin Miao

Ningbo University ( email )

China

Cai-Jun Zheng

affiliation not provided to SSRN ( email )

No Address Available

Jing Zhang

Ningbo University ( email )

China

Wei Xu

Ningbo University ( email )

China

Jia-Cheng Li

Ningbo University ( email )

China

Kai Wang

Soochow University ( email )

No. 1 Shizi Street
Taipei, 215006
Taiwan

Xiao-Hong Zhang

Soochow University ( email )

No. 1 Shizi Street
Taipei, 215006
Taiwan

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