Novel heteroleptic iridium(III) complexes with a 2-(1H-pyrazol-5-yl)pyridine derivative containing a carbazole group as ancillary ligand: Synthesis and application for polymer light-emitting diodes

• Published in: Synthetic metals Vol. 187; pp. 209 - 216
• Main Authors: Tang, Huaijun, Wei, Liying, Wang, Jianbin, Li, Yanhu, Wu, Hongbin, Yang, Wei, Cao, Yong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2014; Elsevier
• Subjects: Ancillary ligand; Application fields; Applied sciences; Carbazole; Energy; Exact sciences and technology; Heteroleptic iridium(III) complex; Natural energy; Photovoltaic conversion; Polymer industry, paints, wood; Polymer light-emitting diode; Pyrazole; Solar cells. Photoelectrochemical cells; Solar energy; Technology of polymers; Heteroleptic iridium(III) complex; Carbazole; Polymer light-emitting diode; Pyrazole; Ancillary ligand; Amorphous material; Iridium III Complexes; Carbazole derivatives; Photoluminescence; Organic ligand; Electroluminescence; Luminescent material; Experimental study; Carbazole(vinyl) polymer; Absorption spectrum; Thermal stability; Pyridine derivatives; Electrochemical properties; Organic light emitting diodes; Pyrazole derivatives; Doped polymer; Chemical synthesis
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2013.11.020

•Using a novel non-β-diketonate ancillary ligand.•Tg are 171°C, 172°C and 165°C, ΔT5% are 411°C, 406°C and 433°C.•Lmax are 4948cdm−2, 11,215cdm−2 and 4696cdm−2, LEmax are 11.6cdA−1, 25.2cdA−1 and 16.4cdA−1. A novel organic compound 9-(2-ethylhexyl)-3-(5-(pyridin-2-yl)-1H-pyrazol-3-yl)-9H-carbazole (PPC) was synthesized and used as ancillary ligand in heteroleptic iridium(III) complexes (npy)2Ir(PPC), (ppy)2Ir(PPC) and (dfppy)2Ir(PPC) (npy: 2-(naphthalen-1-yl)pyridine; ppy: 2-phenylpyridine; dfppy: 2-(2,4-difluorophenyl)pyridine). All of the iridium(III) complexes are amorphous and have high thermal stability. Their glass-transition temperatures are 171°C, 172°C and 165°C, and 5% weight-reduction temperatures are 411°C, 406°C and 433°C, respectively. The polymer light-emitting diodes using the iridium(III) complexes as phosphorescent dopants exhibited good EL performance, the maximum luminances of (npy)2Ir(PPC), (ppy)2Ir(PPC) and (dfppy)2Ir(PPC) are 4948cdm−2, 11215cdm−2 and 4696cdm−2, and the maximum current efficiencies are 11.6cdA−1, 25.2cdA−1 and 16.4cdA−1, respectively. The CIEs of their devices are around (0.59, 0.40), (0.31, 0.57) and (0.32, 0.54), respectively.