M. G. Kaplunov

Polytriphenylamine derivatives as materials for hole transporting layers in electroluminescent devices

A novel, high Tg (ca. 185°C) material for hole-transporting layers has been synthesized. Combination with a 1,2,4-triazole derivative yields an effective blue light-emitting device.

Near-IR and ESR studies of the radical anions of C60 and C70 in the system fullerene-primary amine

It is shown by near-IR that the anion radicals C 70 − and C 70 2- are formed in vacuum by interaction between the fullerenes C 70 and 1-amino-3-propanol (AP) and 1,5-diaminopentane (DAP). The temperature dependence of the ESR spectra for the systems C 60 -AP, C 70 -AP and C 70 -DAPA were studied. At low temperature (15–45 K) the ESR spectrum for C 60 − is similar to that for species with an axially symmetric g-factor . The anisotropy of the signals is averaged out with increasing temperature. The averaged line broadens with further temperature growth, the sharp signal at g = 2.0001 being superimposed on this wide line. The ESR spectrum in the system C 70 -AP at 12.5 K may be tentatively described as a superposition of two ESR spectra, namely the ESR of a radical (assumed to be a cation radical) and of C 70 − .

Exciplex electroluminescence and photoluminescence spectra of the new organic materials based on zinc complexes of sulphanylamino-substituted ligands

We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material.

New Organic Electroluminescent Materials

ABSTRACT Spectral and electric properties of five new materials for electroluminescent devices are described including materials for emitting layers and a high-Tg hole-transporting material.

Hybrid organic-inorganic light-emitting diodes

We demonstrate the hybrid organic-inorganic LEDs based on GaN and InGaN blue emitters with some organic luminophores providing blue, green, red and white emission colors with high luminous efficiency. The color of the emitted light from the GaN-based LED can be changed by varying the current through the device due to change in the relation between the UV and visible components of GaN electroluminescence.

New Organic Electroluminescent Materials Based on Chelate Metal Complexes

We have synthesized some new chelate metal complexes based on 8-mercaptoquinoline and 8-aminoquinoline derivatives with different metals (Zn, Cd, Ga) and studied their spectral and electroluminescent properties. This is the first use of the compounds containing other heteroatoms instead of oxygen atoms in chelate cycles for OLED applications. The new compounds are characterized by blue and green luminescence. OLEDs prepared on the base of the new materials exhibit bright light emission with an efficiency of about 10 cd/A.

A new class of electroluminescent metal complexes based on quinoline ligands containing the sulfanylamino group

The synthesis and properties of a new class of electroluminescent metal complexes based on quinoline ligands containing the sulfanylamino group in position 8 are described. These complexes contain C-N-M-N chains in the chelate cycles instead of the traditionally used C-O-M-N chains.

Electroluminescent Devices Based on Novel Zinc Complexes of Sulphonylamino Substituted Heterocycles

The electroluminescent properties of some new materials based on novel zinc complexes of sulphonylamino substituted quinolines and 2-phenylbenzazoles are reported. The electroluminescent devices based on the new complexes exhibit a bright luminosity of green or nearly white color with good luminosity efficiency up to 25–30 cd/Å.

Exciplex Electroluminescence Spectra of the New Organic Materials Based on Zinc Complexes of Sulphanylamino-Substituted Ligands

The emission spectra of the electroluminescent devices based on novel zinc complexes of sulphonylamino substituted quinolines, 2-phenylbenzazoles, and oxadiazoles are reported. The spectra exhibit wide intensive bands probably of exciplex nature. The exciplex formation can probably be due to the interaction of nitrogen atoms of amino substituents of a zinc complex and amino-containing molecules of a hole-transporting layer.

Electronic excitation energy transfer in solid solution of 7-diethylamino-3,4-benzophenoxazine-2-one (Nile Red dye) in bis[N-2-(oxybenzylidene)-4-tert-butylaniline]zinc

Transfer of electronic excitation energy from the host material to guest molecules was studied taking the solid-phase system bis[N-(2-oxybenzylidene)-4-tert-butylaniline]zinc + 7-diethylamino-3,4-benzophenoxazine-2-one (the guest compound) as an example. The luminescence excitation spectra and the concentration quenching of green fluorescence of the host compound and the excitation of sensitized red fluorescence of the guest molecules were studied. Among the exciton mechanism of energy migration and Försters long-range, single-jump mechanism, the former dominates. The number of jumps (m) and the mean diffusion length of the singlet exciton (l), calculated in the framework of the model of partially delocalized, randomly hopping exciton, were estimated at ≈1.5·103 and ≈450 Å, respectively.