Highly Efficient Blue LECs Using Charged Iridium Complexes
K. Wongkhana, U. Mahanitiponga, M. Srikaewa, Y. Tantirunggrotchaib, S. Sahasithiwatc, R. Jitchatia
aDepartment of Chemistry, Faculty of Science,Ubon Ratchathani University, Ubon Ratchathani Province, 34190, Thailand
bNational Metal and Materials Technology Center, 114 Thailand Science Park, Pahol-yothin Rd., Klong 1, Khlong Luang, Pathumthani 12120, Thailand
cDepartment of Chemistry, Faculty of Science and Technology, Thammasat University, Pathumthani, 12120 Thailand
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Two heteroleptic charged iridium (III) species comprising two cyclometallating ligands and a neutral diimine ligand were synthesized and characterized, namely [(3,4,7,8-tetramethyl-1,10-phenanthroline-N-N')-bis-(2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine-C6',N)-iridium (III)]hexafluorophosphate (UM01) and [(3,4,7,8-tetramethyl-1,10-phenanthroline-N-N')-bis-(2-(2',4'-difluoro-phenyl)-1H-pyrazole-C6',N)-iridium (III)]hexafluorophosphate (UM02). Both complexes were used as the blue emitter in OLED and LEC devices. We found that the optimized structure is ITO/PEDOT:PSS/complex:BMIMPF6(1:1)/Al. The UM01 gave a current efficiency of 1.14 cd A-1, whereas the UM02 shows a better CIE coordination at 0.19, 0.40.

DOI: 10.12693/APhysPolA.127.1109
PACS numbers: 85.60.Bt; 85.60.Jb