Two-Channel Space Charge Transfer-Induced Thermally Activated Delayed Fluorescent Materials for Efficient OLEDs with Low Efficiency Roll-Off

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Ruifang Wang
  • Zhiyi Li
  • Taiping Hu
  • Lei Tian
  • Xiaoxiao Hu
  • Shihao Liu
  • Yuanping Yi
  • Pengfei Wang
  • Ying Wang

Detail(s)

Original languageEnglish
Pages (from-to)49066-49075
Journal / PublicationACS Applied Materials and Interfaces
Volume13
Issue number41
Online published6 Oct 2021
Publication statusPublished - 20 Oct 2021

Abstract

Enhancing the reverse intersystem crossing (RISC) process of thermally activated delayed fluorescent (TADF) emitters is an effective approach to realize efficient organic light-emitting diodes (OLEDs) with low efficiency roll-off. In this work, we designed two novel TADF emitters, SAT-DAC and SATX-DAC, via a spiro architecture. Efficient maximum external quantum efficiencies (EQEs) of 22.6 and 20.9% with reduced efficiency roll-off (EQEs of 17.9 and 17.0% at 1000 cd m-2) were achieved via a "two-RISC-channel" strategy. X-ray diffraction shows close donor (D)/acceptor (A) spacing and suitable D/A orientation in crystals of the two emitters favoring both intra- and intermolecular through-space charge transfer (TSCT) processes. Transient photoluminescence decay measurements show that both emitters have two RISC channels leading to kISCT exceeding 106 s-1. These results suggest that the "two-RISC-channel" design can be a novel approach for enhancing performance of TADF emitters, in particular at high excitation densities.

Research Area(s)

  • efficiency roll-off, spiro-structure, thermally activated delayed fluorescence, through-space charge transfer, two-channel RISC

Citation Format(s)

Two-Channel Space Charge Transfer-Induced Thermally Activated Delayed Fluorescent Materials for Efficient OLEDs with Low Efficiency Roll-Off. / Wang, Ruifang; Li, Zhiyi; Hu, Taiping; Tian, Lei; Hu, Xiaoxiao; Liu, Shihao; Cao, Chen; Zhu, Ze-Lin; Tan, Ji-Hua; Yi, Yuanping; Wang, Pengfei; Lee, Chun-Sing; Wang, Ying.

In: ACS Applied Materials and Interfaces, Vol. 13, No. 41, 20.10.2021, p. 49066-49075.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review