Two novel phenanthrene-based host materials in red and green organic light-emitting devices with low efficiency roll-offElectronic supplementary information (ESI) available. See DOI: 10.1039/c8nj03787f

• Main Authors: Wang, Yuanyuan, Song, Wenxuan, Zhou, Li, Liang, Wenting, Mu, Haichuan, Huang, Jinhai, Su, Jianhua
• Format: Journal Article
• Published: 05.11.2018
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj03787f

Two new organic small molecules composed of phenanthrene, carbazole and an electron deficient moiety were synthesized by a Suzuki coupling reaction. It is particularly intriguing to compare the electroluminescent (EL) properties of PBBM and PBTZ , which have the same molecular structure with the respective high T d at around 436 °C and 423 °C. By changing the electron deficient moiety of the C9-position of phenanthrene, the photophysical, electrochemical and electroluminescent properties of these two compounds showed significant differences. Furthermore, green and red phosphorescent organic light emitting diodes (OLEDs) employing PBBM and PBTZ as host materials exhibited low efficiency roll-off, and the red OLEDs based on both compounds revealed better EL performance than those of the green OLEDs. Especially, the PBBM -hosted green and red OLEDs achieved a maximum EQE of 14.3% and 18.2%, respectively. Two novel phenanthrene-based host materials showed significant differences due to the different moieties at the same position of the phenanthrene backbone.