title: Crystal structure, photoluminescence and electroluminescence of three bluish green light-emitting iridium complexes.
abstract: Three bis-cyclometalated iridium complexes ((TPP)2Ir(acac), (TPP)2Ir(tpip) and (TPP)2Ir(pic)) with 2-(2-trifluoromethyl)pyrimidine-pyridine (TPP) as the main ligand, 2,4-pentanedionate (acac), tetraphenylimidodiphosphinate (tpip) and picolinate (pic) as the ancillary ligands, respectively, were prepared. Their photoluminescence and electrochemistry properties were investigated in detail, and (TPP)2Ir(tpip) was also examined by X-ray crystallography. These complexes show bluish green emission with a quantum efficiency of 11-14%. The organic light emitting diodes (OLEDs) with the structure of ITO/TAPC (1,1-bis[4-(di-p-tolylamino)phenyl]cyclohexane, 40 nm)/mCP (1,3-bis(9H-carbazol-9-yl)benzene, 10 nm)/Ir complex (8 wt%):PPO21 (3-(diphenylphosphoryl)-9-(4-(diphenylphosphoryl)phenyl)-9H-carbazole, 25 nm)/TmPyPB (1,3,5-tri(m-pyrid-3-yl-phenyl)benzene, 50 nm)/LiF (1 nm)/Al (100 nm) were fabricated to evaluate the potential application of these complexes. A (TPP)2Ir(tpip) emitter based device showed the best performance of a maximum current efficiency (ηc) value of 37.61 cd A(-1) and a maximum external quantum efficiency (EQE) of 13.7% with low efficiency roll-off.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. yxzheng@nju.edu.cn.
authors.forename: Qiu-Lei
authors.initials: QL
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. yxzheng@nju.edu.cn.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. yxzheng@nju.edu.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. yxzheng@nju.edu.cn.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. yxzheng@nju.edu.cn.
authors.forename: You-Xuan
authors.initials: YX
authors.lastname: Zheng