Controlling Synergistic Oxidation Processes for Efficient and Stable Blue Thermally Activated Delayed Fluorescence Devices

Lin Song Cui, Ya Li Deng, Daniel Ping Kuen Tsang, Zuo Quan Jiang, Qisheng Zhang, Liang Sheng Liao, Chihaya Adachi

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

The degradation mechanism of blue thermally activated delayed fluorescence (TADF) organic light-emitting Diodes (OLEDs) was demonstrated by distinguishing the triplet emitters into three species. To investigate the dependency of the device stability on the T 1 state characterization of TADF emitters, three new bipolar compounds named 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (BCz-TRZ), 2-(9'-phenyl-9H,9'H-[3,3'-bicarbazol]-9-yl)dibenzo[b,d]thiophene 5,5-dioxide (BCz-DBTO), and 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9,9-diphenyl-9,10-dihydroacridine (DPAC-TRZ) were designed and synthesized, and investigated along with a reported blue TADF compound 9'-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9'H-9,3':6',9'-tercarbazole (3Cz-TRZ). These four CT emitters exhibit similar emission spectra with peaks at 480?490 nm in a 10-wt%-doped film of bis (2-(diphenylphosphino)phenyl)ether oxide (DPEPO). The triplet spin density of DPACTRZ is delocalized across the entire molecule, indicating the CT nature of the temperature state of DPAC-TRZ. On the basis of our degradation mechanism of blue TADF OLEDs, the devices employing BCz-TRZ should be more stable than those employing the other three emitters.

Original languageEnglish
Pages (from-to)7620-7625
Number of pages6
JournalAdvanced Materials
Volume28
Issue number35
DOIs
Publication statusPublished - 2016

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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