Ultra-Deep-Blue Aggregation-Induced Delayed Fluorescence Emitters: Achieving Nearly 16% EQE in Solution-Processed Nondoped and Doped OLEDs with CIEy < 0.1

Hyung Jong Kim, Hyunchul Kang, Ji Eun Jeong, Su Hong Park, Chang Woo Koh, Chai Won Kim, Han Young Woo, Min Ju Cho, Sungnam Park, Dong Hoon Choi

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)

Abstract

Ultra-deep-blue aggregation-induced delayed fluorescence (AIDF) emitters (TB-tCz and TB-tPCz) bearing organoboron-based cores as acceptors and 3,6-substituted carbazoles as donors are presented. The thermally activated delayed fluorescence (TADF) properties of the two emitters are confirmed by theoretical calculations and time-resolved photoluminescence experiments. TB-tCz and TB-tPCz exhibit fast reverse intersystem crossing rate constants owing to efficient spin–orbit coupling between the singlet and triplet states. When applied in solution-processed organic light-emitting diodes (OLEDs), the TB-tCz- and TB-tPCz-based nondoped devices exhibit ultra-deep-blue emissions of 416–428 nm and high color purity owing to their narrow bandwidths of 42.2–44.4 nm, corresponding to the Commission International de l´Eclairage color coordinates of (x = 0.16–0.17, y = 0.05–0.06). They show a maximum external quantum efficiency (EQEmax) of 8.21% and 15.8%, respectively, exhibiting an unprecedented high performance in solution-processed deep-blue TADF-OLEDs. Furthermore, both emitters exhibit excellent device performances (EQEmax = 14.1–15.9%) and color purity in solution-processed doped OLEDs. The current study provides an AIDF emitter design strategy to implement high-efficiency deep-blue OLEDs in the future.

Original languageEnglish
Article number2102588
JournalAdvanced Functional Materials
Volume31
Issue number33
DOIs
Publication statusPublished - 2021 Aug 16

Bibliographical note

Funding Information:
H.J.K. and H.K. contributed equally to this work. The authors acknowledge financial support from the National Research Foundation (NRF) of Korea (Nos. NRF2019R1A2C2002647 and NRF2019R1A6A1A11044070), Korea University Grant, and LG Display Co. Limited (Q1927051, 2020). The authors are grateful to Korea Basic Science Institute (KBSI) for allowing the use of MALDI‐TOF MS instrument and Institute for Basic Science (IBS, Korea) for allowing to obtain nuclear magnetic resonance data (NMR; Ascend 500, Bruker).

Funding Information:
H.J.K. and H.K. contributed equally to this work. The authors acknowledge financial support from the National Research Foundation (NRF) of Korea (Nos. NRF2019R1A2C2002647 and NRF2019R1A6A1A11044070), Korea University Grant, and LG Display Co. Limited (Q1927051, 2020). The authors are grateful to Korea Basic Science Institute (KBSI) for allowing the use of MALDI-TOF MS instrument and Institute for Basic Science (IBS, Korea) for allowing to obtain nuclear magnetic resonance data (NMR; Ascend 500, Bruker).

Publisher Copyright:
© 2021 Wiley-VCH GmbH.

Keywords

  • aggregation-induced emission
  • nondoped organic light emitting diodes
  • solution processes
  • thermally activated delayed fluorescence
  • ultra-deep-blue emitters

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics

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