High stability and luminescence efficiency in donor–acceptor neutral radicals not following the Aufbau principle

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Haoqing Guo
  • Qiming Peng
  • Qinying Gu
  • Shengzhi Dong
  • Emrys W. Evans
  • Alexander J. Gillett
  • Xin Ai
  • Ming Zhang
  • Dan Credgington
  • Veaceslav Coropceanu
  • Richard H. Friend
  • Jean-Luc Brédas
  • Feng Li

Detail(s)

Original languageEnglish
Pages (from-to)977-984
Journal / PublicationNature Materials
Volume18
Issue number9
Online published22 Jul 2019
Publication statusPublished - Sept 2019
Externally publishedYes

Abstract

With their unusual electronic structures, organic radical molecules display luminescence properties potentially relevant to lighting applications; yet, their luminescence quantum yield and stability lag behind those of other organic emitters. Here, we designed donor–acceptor neutral radicals based on an electron-poor perchlorotriphenylmethyl or tris(2,4,6-trichlorophenyl)methyl radical moiety combined with different electron-rich groups. Experimental and quantum-chemical studies demonstrate that the molecules do not follow the Aufbau principle: the singly occupied molecular orbital is found to lie below the highest (doubly) occupied molecular orbital. These donor–acceptor radicals have a strong emission yield (up to 54%) and high photostability, with estimated half-lives reaching up to several months under pulsed ultraviolet laser irradiation. Organic light-emitting diodes based on such a radical emitter show deep-red/near-infrared emission with a maximal external quantum efficiency of 5.3%. Our results provide a simple molecular-design strategy for stable, highly luminescent radicals with non-Aufbau electronic structures.

Citation Format(s)

High stability and luminescence efficiency in donor–acceptor neutral radicals not following the Aufbau principle. / Guo, Haoqing; Peng, Qiming; Chen, Xian-Kai et al.
In: Nature Materials, Vol. 18, No. 9, 09.2019, p. 977-984.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review