Sung Min Kim

Modified Julolidine-Containing Emitters for Red Organic Light-Emitting Diodes

The compounds 2.1.1-(2-(4-pentylbicyclo[2.2.2]octan-1-yl)-6-(2-(1,1,7,7-tetramethyl-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile (Red 1) and 2-(2-(2-(1,1-dimethyl-7,7-bis((trimethylsilylmethyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-6-(4-pentylbicyclo[2.2.2]octan-1-yl)-4H-pyran-4-ylidene)malononitrile (Red 2) with modified julolidine moieties were developed and synthesized. To determine the electroluminescence properties of these materials, multilayered organic light-emitting diodes (OLEDs) were fabricated with a device structure of indium tin oxide (ITO)/N,N-diphenyl-N,N-(1-napthyl)-(1,1-phenyl)-4,4-diamine (50 nm)/tris(8-quinolinolato)-aluminum (Alq3):dopants Red 1 and Red 2 (30 nm, 1–5%)/Alq3 (50 nm)/8-hydroxyquinolatolithium (2 nm)/Al. All devices exhibited efficient red emission. In particular, a device using Red 2 as the dopant material showed a maximum luminance of 1455 cd/m2 at 12.0 V, and maximum luminous and power efficiencies of 1.71 cd/A and 1.32 lm/W, respectively. The Commission Internationale de lEclairage coordinates of this device were (0.64,0.36) at 7.0 V, which indicated stable color chromaticity at various voltages.

Synthesis and Application of the Aromatic Spacered Azomethine Metal Complexes for the Organic Electroluminescent Devices

Abstract The new azomethine metal complexes were synthesized and three complexes among them were applied to the organic electroluminescent devices as a blue or white light-emitting layer. Emission wavelengths were observed at the region of 420–540 nm in luminescence spectra for these complexes. Their HOMO, LUMO and band gaps were investigated with cyclic voltammetry and found to be consistent with their UV-vis absoption spectral data.

Synthesis of new boron complexes containing aromatic moieties and their application to organic electroluminescent devices

Abstract The boron complexes coordinated with the anion of 2,3-dihydroxynaphthalene (DHN) or 2,3-dihydroxyquinoxaline (DHQx) were synthesized and applied to the organic electroluminescent devices as a blue light emitting layer. Emission peaks were observed at 480 and 430 nm in photoluminescence spectra of (DHQx) 3 B and Ph 2 B(DHN), respectively. The electroluminescent devices containing the emitting layer of Ph 2 B(DHN) showed greenish blue luminescence with the maximum emission peak at 498 nm. The ionization potential, electron affinity and electrochemical gap of (DHQx) 3 B and of Ph 2 B(DHN) were investigated with cyclic voltammetry and found to be consistent with their UV–vis absorption spectral band gap.

White-Light-Emitting Materials for Organic Electroluminescent Devices

Abstract A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) (Zn(BTZ)2) was known to show white emission with a broad electroluminescence[1–2]. In this study, the electroluminescent characteristics of Be(BTZ)2 and Mg(BTZ)2, as well as Zn(BTZ)2 were investigated using organic electroluminescent devices with the structure of ITO/TPD/Be(BTZ)2, Mg(BTZ)2, or Zn(BTZ)2 /Al. It was found that the device containing Be(BTZ)2 shows the highest power efficiency.

Synthesis of metal complexes chelated with N-naphthalenyl aminomethyl phenol and their application to OELD

Abstract The metal complexes chelated with N-naphthalenyl aminomethyl phenol were synthesized and the beryllium complex was applied to the organic electroluminescent devices as a blue light-emitting layer. Emission wavelength was observed at 406nm in luminescence spectra for this complex. Its ionization potential (IP), electron affinity (EA) and band gap were investigated with cyclic voltammetry and found to be consistent with their UV-vis absoption spectral data.