Original Article

Polymer Journal (2017) 49, 197–202; doi:10.1038/pj.2016.82; published online 21 September 2016

Aggregation-induced delayed fluorescence from phenothiazine-containing donor–acceptor molecules for high-efficiency non-doped organic light-emitting diodes

Naoya Aizawa1, Chao-Jen Tsou1,2, In Seob Park1,3 and Takuma Yasuda1,2,3

  1. 1INAMORI Frontier Research Center (IFRC), Kyushu University, Fukuoka, Japan
  2. 2Department of Automotive Science, Graduate School of Integrated Frontier Sciences, Kyushu University, Fukuoka, Japan
  3. 3Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka, Japan

Correspondence: Dr N Aizawa or Professor T Yasuda, INAMORI Frontier Research Center (IFRC), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan. E-mail: aizawa@ifrc.kyushu-u.ac.jp or yasuda@ifrc.kyushu-u.ac.jp

Received 21 June 2016; Revised 27 July 2016; Accepted 1 August 2016
Advance online publication 21 September 2016

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Abstract

Highly luminescent donor–acceptor molecules based on a phenothiazine donor unit coupled with a xanthone or benzophenone acceptor unit were developed for use in organic light-emitting diodes (OLEDs). While both molecules are almost non-luminescent in pure tetrahydrofuran (THF) solution, a strong yellow delayed fluorescence was observed upon their aggregation in THF/water mixtures or in neat films. This result demonstrates the unique aggregation-induced delayed fluorescence (AIDF) characteristics of these molecules. OLEDs using these AIDF materials as a non-doped emission layer achieved high external electroluminescence quantum efficiencies of up to 11%, which exceeds the theoretical maximum for conventional fluorescent OLEDs.