New hole transport styrene polymers bearing highly π-extended conjugated side-chain moieties for high-performance solution-processable thermally activated delayed fluorescence OLEDs

Ji Hye Lee, Jinhyo Hwang, Chai Won Kim, Amit Kumar Harit, Han Young Woo, Hyung Jong Kim, Yong Woo Kim, Dae Hyuk Choi, Min Ju Cho, Dong Hoon Choi

Research output: Contribution to journalArticlepeer-review

Abstract

Two new hole transport styrene polymers, 2DMFCz and 2DBFCz, were successfully synthesized via radical polymerization. The design concept aims to investigate the hole-transporting ability and energy-level tunability by introducing bis(9,9-dimethyl-9H-fluoren-2-yl)aminocarbazole and bis(dibenzo[b,d]furan-2-yl)aminocarbazole as side-chain pendants. They were found to show good solubility in chlorobenzene but poor solubility in toluene, similar to poly(9-vinylcarbazole) (PVK). The highest occupied molecular orbital levels of 2DMFCz and 2DBFCz were determined to be -5.23 eV and -5.31 eV, respectively, while hole mobilities were estimated to be 1.65 × 10-7 cm2 V-1 s-1 and 1.48 × 10-8 cm2 V-1 s-1 measured by the space-charge limited-current method. Subsequently, in solution-processed green thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs), the 2DMFCz- and 2DBFCz-based devices exhibited a relatively low turn-on voltage of 2.7 V and higher maximum external quantum efficiencies of 23.84% and 21.11%, respectively. These values were superior to those of a PVK-based device. The polymer hole-transport materials presented in this study are promising materials that can play a significant role in improving the performance of TADF-OLEDs fabricated through a solution process in the future. This journal is

Original languageEnglish
Pages (from-to)1692-1699
Number of pages8
JournalPolymer Chemistry
Volume12
Issue number11
DOIs
Publication statusPublished - 2021 Mar 21

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • Organic Chemistry
  • Polymers and Plastics

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