Achievement of high efficiency with extremely low efficiency roll-off in solution-processed thermally activated delayed fluorescence OLEDs manufactured using xanthone-based bipolar host materials

Chae Yeong Kim, Chiho Lee, Hyung Jong Kim, Jinhyo Hwang, Mallesham Godumala, Ji Eun Jeong, Han Young Woo, Min Ju Cho, Sungnam Park, Dong Hoon Choi

Research output: Contribution to journalArticle

Abstract

The use of soluble host materials and thermally activated delayed fluorescence (TADF) emitters is indispensable for developing high-efficiency organic light-emitting diodes (OLEDs) by cost-effective solution processes. In this study, two bipolar hosts were designed as structural isomers, namely 3-(3,5-di(9H-carbazol-9-yl)phenyl)-9H-xanthen-9-one (Xp-mCP) and 2-(3,5-di(9H-carbazol-9-yl)phenyl)-9H-xanthen-9-one (Xm-mCP). The two host materials were synthesized by combining the unipolar host, 1,3-di(9H-carbazol-9-yl)benzene (mCP) with 9H-xanthen-9-one as an electron-accepting moiety. The two hosts exhibit good solubility in various organic solvents and high triplet energy (ET= 2.67 eV forXp-mCPandET= 2.82 eV forXm-mCP), which renders them suitable for t4CzIPN-containing solution-processable green TADF-OLEDs. The maximum external quantum efficiency (EQE) values were 19.3% and 22.0% forXp-mCP- andXm-mCP-based green TADF-OLED, respectively. Among them, the device comprisingXm-mCPshowed an excellent efficiency roll-off behavior by displaying only a 4.5% decrease and 11.4% decrease at 1000 cd m-2and 2000 cd m-2, respectively. These results show the significant potential of xanthone-mCP host materials to develop solution-processable OLED technologies.

Original languageEnglish
Pages (from-to)6780-6787
Number of pages8
JournalJournal of Materials Chemistry C
Volume8
Issue number20
DOIs
Publication statusPublished - 2020 May 28

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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