We report on the design, synthesis, and characterization of four new heteroleptic iridiu
m(III) co
mplexes bearing 2鈥?6鈥?difluoro-2,3鈥?bipyridine and pyridyl-azole ligands. The photophysical properties and cyclic volta
mmetry of the co
mplexes were also investigated. All co
mpounds display highly efficient genuine blue phosphorescence (位
max ca. 440 n
m), at roo
m te
mperature in solution and in thin fil
m, with quantu
m yield in the range 0.77鈥?.87 and 0.62鈥?.93, respectively. We found that introduction of the bulky
tert-butyl substituents on the cyclo
metalated or azolated chelates can effectively reduce detri
mental aggregation, which results in a loss of color purity. Co
mprehensive density functional theory (DFT) and ti
me-dependent DFT (TD-DFT) approaches have been perfor
med on the ground and excited states of the here reported co
mplexes, in order to gain deeper insights into their structural and electronic features as well as to ascertain the nature of the excited states involved into the electronic absorption processes. Moreover, electron spin density analysis and total electron density difference at the lowest-lying triplet state (T
1) were perfor
med for shedding light onto the nature of the e
mitting excited state. Finally, the fabrication of the organic light-e
mitting diodes (OLEDs), e
mploying the bulkiest derivative a
mong the here reported phosphorescent dopants, was successfully
made. The devices exhibit re
markable
maxi
mu
m external quantu
m efficiency (EQE) as high as 7.0%, in nonopti
mized devices, and power efficiency (PE) of 4.14 l
m W
鈥?, together with a true-blue chro
maticity CIE
x,y = 0.159, 0.185 recorded at 300 cd
m鈥?.
Keywords:
m+complexes&qsSearchArea=searchText">iridium complexes; mission&qsSearchArea=searchText">blue-emission; phosphorescence; mitting+diode&qsSearchArea=searchText">organic-light emitting diode; pyridil-azolate ligand