Naphthyl or pyrenyl substituted 2-phenylcarbazoles as hole transporting materials for organic light-emitting diodes

• Published in: Dyes and pigments 2017-01, Vol.136, p.302-311
• Main Authors: Chang, Chih-Hao, Krucaite, Gintare, Lo, Dain, Chen, Yun-Lan, Su, Chu-Chun, Lin, Tzu-Chun, Grazulevicius, Juozas Vidas, Peciulyte, Laura, Grigalevicius, Saulius
• Format: Article
• Language: English
• Subjects: Hexylcarbazole; Hole transporting materials; Naphthyl; Organic light-emitting diodes; Phosphorescent; Pyrenyl
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2016.08.056

A new series of 9-hexylcarbazole-based hole transporting materials (HTM) with naphthyl or pyrenyl substitutions were synthesized and characterized. The respective glass transition temperatures of the new HTM were estimated to be 58 and 61 °C, which can provide morphologically-stable films for electroluminescence (EL) applications. The pyrenyl substituted analogue possesses an adequate ionization potential and triplet energy gap of 5.54 eV and 2.48 eV, respectively, which makes it a suitable HTM for use in red phosphorescent organic light-emitting diodes (OLEDs). In contrast, the ionization potential of the naphthyl substituted analogues was estimated to be 5.72 eV, thus the p-type conducting dopant should be introduced for device fabrication. The respective peak efficiencies of the naphthyl and pyrenyl based OLEDs with the p-type dopant were recorded at 15.4% (26.0 cd/A and 24.2 lm/W) and 17.3% (26.1 cd/A and 19.1 lm/W), demonstrating their high potential for EL applications. [Display omitted] •9-Hexylcarbazole-based HTM with naphthyl or pyrenyl substitutions were synthesized.•The hexylcarbazole-based HTMs possess adequate ionization potentials.•The hexylcarbazole-based HTMs are appropriate host materials for p-type dopants.•Red PhOLEDs using the 9-hexylcarbazole derivatives as HTMs.