π-Extended Carbazole Derivatives as Host Materials for Highly Efficient and Long-Life Green Phosphorescent Organic Light-Emitting Diodes

Ayato Arai, Hisahiro Sasabe, Kohei Nakao, Yuki Masuda, Junji Kido

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

High-performance organic light-emitting diodes (OLEDs) that use phosphorescent and/or thermally activated delayed fluorescence emitters are capable of realizing 100 % electron-to-photon conversion. The host materials in these OLEDs play crucial roles in determining OLED performance. Carbazole derivatives are frequently used as host materials, among which 3,3-bis(9H-carbazol-9-yl)biphenyl (mCBP) is often used for lifetime testing in scientific studies. In this study, the π conjugation of the carbazole unit was expanded to enhance OLED lifetime by designing and developing two benzothienocarbazole (BTCz)-based host materials, namely m1BTCBP and m4BTCBP. Among these host materials, m1BTCBP formed a highly efficient [Ir(ppy)3]-based OLED with an operational luminescence half-life (LT50) of over 300 h at an initial luminance of approximately 12000 cd m−2 (current density: 25 mA cm−2). The LT50 value at 1000 cd cm−2 was estimated to be about 23 000 h. This performance is clearly higher than that of mCBP-based OLEDs (LT50≈8500 h).

Original languageEnglish
Pages (from-to)4971-4976
Number of pages6
JournalChemistry - A European Journal
Volume27
Issue number15
DOIs
Publication statusPublished - Mar 12 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

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