Charge mobilities and luminescence characteristics of blue-light emitting bent carbazole trimers connected through vinylene linkers - Effect of nitrile substituents

Bong Soo Kim, Sung Hoon Joo, Dongkeun Oh, Soon Wook Cha, Don Soo Choi, Cheol Eui Lee, Jung Il Jin

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Two new blue-light emitters, 3,6-bis(4-carbazolylstyryl)-N-4- methylphenylcarbazole (Cz3) and 3,6-bis[4-(3,6-dicyanocarbazolyl) styryl]-N-4-methylphenylcarbazole (Cz3(CN)4), were found to form high glass-transition temperature (Tg), amorphous organic glasses, when vacuum deposited. Cz3(CN)4 exhibited a much higher Tg value (242°C) than Cz3 (163°C). It was found that Cz3 is an excellent hole transporter (μh+ = 1.3 × 10-4cm2/Vs, μe- = 2.8 × 10-8cm2/Vs) while Cz3(CN)4 shows a faster electron mobility (μe- = 3.1 × 10-6cm2/Vs) than hole mobility (μh+ = 2.0 × 10 -8cm2/Vs), which is perceived to tell us that the presence of the electron-attracting nitrile (C≡N) groups facilitates the electron mobility. The single layer electroluminescence (EL) device (ITO/EML/Li:Al) of Cz3(CN)4 performed much better (external quantum efficiency ∼3.0 × 10-2%) than that of Cz3 (external quantum efficiency ∼1.2 × 10-3%).

Original languageEnglish
Pages (from-to)229-235
Number of pages7
JournalSynthetic Metals
Volume145
Issue number2-3
DOIs
Publication statusPublished - 2004 Sep 21

Keywords

  • Electroluminescence
  • Light sources
  • Organic semiconductor based on molecules

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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