Liquid-Crystalline Thermally Activated Delayed Fluorescence: Design, Synthesis, and Application in Solution-Processed Organic Light-Emitting Diodes

Yuanyuan Zhu, Songkun Zeng, Bing Li, Alice J. McEllin, Junxu Liao, Zhou Fang, Chen Xiao, Duncan W. Bruce*, Weiguo Zhu, Yafei Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Realizing both high efficiency and liquid crystallinity in one molecule remains a challenge in thermally activated delayed fluorescence (TADF) emission. Herein, two isomeric compounds- m-DPSAc-LC and p-DPSAc-LC with different connection positions between donor and acceptor moieties- were synthesized and characterized. Diphenylsulfone (DPS) was used as the acceptor, acridine (Ac) was used as the donor, and biphenyl derivatives (LC) were employed as the mesogenic group. Both compounds showed a smectic mesophase evidenced by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and temperature-dependent small-angle X-ray scattering (SAXS). The compound p-DPSAc-LC clearly exhibited thermally activated delayed fluorescence due to the much more distorted geometry, whereas m-DPSAc-LC showed simple fluorescence. Compared to the parent TADF molecules without appended mesogenic groups (DPS-Ac), these liquid-crystalline emitters possessed higher hole mobilities and improved device performance. The OLEDs fabricated via solution processing using the liquid-crystalline compound p-DPSAc showed a maximum external quantum efficiency of ∼15% and as such is the first example of a liquid-crystalline TADF material in an OLED device.

Original languageEnglish
Pages (from-to)15437–15447
Number of pages11
JournalACS Applied Materials and Interfaces
Issue number13
Early online date24 Mar 2022
Publication statusPublished - 6 Apr 2022

Bibliographical note

Funding Information:
Financial support was provided by the National Natural Science Foundation of China (Nos. 51773021, 51911530197) and the Six Talent Peaks project in Jiangsu Province (XCL-102). DWB and YW thank the Royal Society and the NSFC for an International Joint Project Grant, and AJM thanks the University of York for financial support. The NMR testing was provided by Analysis and Testing Center, NERC Biomass of Changzhou University.

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  • acridine
  • diphenylsulfone
  • liquid crystal
  • solution-processable OLED
  • synthesis and properties
  • thermally activated delayed fluorescence

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