Hoe-Joo Seo

Blue phosphorescent iridium(III) complexes containing carbazole-functionalized phenylpyridine for organic light-emitting diodes: energy transfer from carbazolyl moieties to iridium(III) cores

By introducing a hexylcarbazolyl substituent into a phenylpyridine-based ligand, a Forster energy transfer from the carbazole moieties to the Ir(III) cores was observed in the heteroleptic cyclometalated Ir(III) complexes, resulting in an enhancement of luminescent efficiency. The phosphorescent OLED gave CIE coordinates of (0.21, 0.55) with a maximum external quantum efficiency of 7.16%.

Green phosphorescent light-emitting diodes from polymer doped with iridium complex

We demonstrate efficient organic light-emitting diodes by using a phosphorescent host/guest system consisting of a recently developed green electrophosphorescent molecule, bis[(4,6-difluorophenyl)-8-methylpyridinato-N,C2′)iridium pyrazinate [(dfmppy)2Irprz], as the guest and a blend of poly(N-vinylcarbazole) (PVK) with 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as the host and different cathode structures such as a triple layer of BAlq∕LiF∕Al and a bilayer of CsF∕Al. The electrophosphorescence emission was characteristic of (dfmppy)2Irprz, with its maximum at 563nm with Commission International de L’Eclairage coordinates of (0.43, 0.53). The device with 0.5wt% of (dfmppy)2Irprz in PVK/PBD (60:40wt%) with a CsF (2nm)∕Al bilayer exhibited an external quantum efficiency of 6.2%, luminescence efficiency of 17.3cd∕A, luminous power efficiency of 24.2lm∕W, and maximum brightness of 10220cd∕m2.

[Benzyl(2-pyridylmeth­yl)amine]dichloridomercury(II)

The Hg atom in the title compound, [HgCl2(C13H14N2)], adopts a distorted tetrahedral geometry, being ligated by two N atoms of the benzyl(2-pyridylmethyl)amine (bpma) ligand and two Cl atoms. The dihedral angle between the least-squares planes through the chelate ring and Cl—Hg—Cl atoms is 85.4 (1)°. The phenyl ring on the bpma ligand is twisted out of the pyridine plane, forming a dihedral angle of 76.0 (3)°. Disorder in this ring is also noted with two coplanar conformations having equal site occupancies.

Dichlorido[N,N-diethyl-N'-(2-pyridyl-methyl-ene)ethane-1,2-diamine]mercury(II).

The Hg atom in the title compound, [HgCl2(C12H19N3)], adopts a distorted trigonal-bipyramidal geometry, being ligated by two Cl atoms and three N atoms of the N,N-diethyl-N′-(2-pyridylmethylene)ethane-1,2-diamine ligand. The dihedral angle between the HgN3 and HgCl2 least-squares planes is 88.6 (1)°. The Hg—N distances including the pyridine N and the ammonium N atom are about 0.20 Å longer than the Hg—N distance including the imino N atom.

Bis[3,5-difluoro-2-(4-methyl­pyridin-2-yl)phenyl-κ2C1,N](picolinato-κ2N,O)iridium(III) chloro­form monosolvate

In the title complex, [Ir(C12H8F2N)2(C6H4NO2)]·CHCl3, two similar molecules of each component comprise the asymmetric unit. The independent complex molecules are linked by intermolecular π–π interactions [centroid–centroid distance = 3.830 (4) Å]. The IrIII ion adopts a distorted octahedral geometry, being coordinated by three N atoms, two C atoms, and one O atom of three bidentate ligands, with the N atoms arranged meridionally.