• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1457-1460
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• 2007

To understand the electronic charge transfer from cathode to an ETL in the TEOLED, the pristine $Alq_3$ thin film and the interfaces of both $Alq_3/Ba$ and $Alq_3/Au$ were investigated by using the NEXAFS spectroscopy. The unoccupied energy state of each interface using the NEXAFS Analyses at the C and OK-edges was assigned and charge transfer from Ba to ${\pi}^{\ast}$ of $Alq_3$ was investigated in detail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1098-1101
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• 2003

Complex impedances with frequency and voltage variation were analyzed in ITO/$Alq_3$/Al device structure at thickness 100 nm and 200 nm of $Alq_3$, respectively. At low frequency, complex impedance is mostly expressed by resistive component, and at the high frequency by capacitive component. Also, we have evaluated resistance, capacitance and permittivity.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.154-156
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• 2005

In the device structure of ITO/tris (8-hydroxyquinoline) aluminum(Alq3)/Al, we investigated the Organic Light-Emitting Diodes (OLEDs) properties as a function of the deposition rate of the $Alq_3$. The deposition rate was from 0.5 to 2.0 $[{\AA}/s]$ in a base pressure of $5{\times}10^{-6}$ [Torr]. It was found that a $Alq_3$ deposition rate of around 1.5 $[{\AA}/s]$ is the optimum for the maximum luminous properties. The optimum deposition rate of $Alq_3$ is 1.5 $[{\AA}/s]$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.477-478
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• 2005

The devices with a structure of ITO/$Alq_3$/Al were fabricated and their impedance properties were analyzed. It is obtained that an effect of resistance $R_p$ of the device was dominant at the low frequency and the high voltage region, emitting region, and it is ignored at the high frequency region. Capacitance $C_p$ appears intensely in a range of all frequencies of non-emitting region, below turn on voltage.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.51-55
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• 2006

The green emitting high performance OLEDs using the $Alq_3$-C545T fluorescent system have been fabricated and characterized. In the device fabrication, 2-TNATA [4,4',4'-tris(2-naphthylphenyl-phenylamino)-triphenylamine] as a hole injection material and NPB [N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] as a hole transport material were deposited on the ITO(indium thin oxide)/glass substrate by vacuum evaporation. And then, green color emission layer was deposited using $Alq_3$ as a host material and C-545T[10-(2-benzothiazolyl)-1,1,7,7- tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]/benzopyrano[6,7,8-ij]-quinolizin-11-one] as a dopant. Finally, small molecule OLEDs with structure of ITO/2-TNATA/NPB/$Alq_3$:C545T/$Alq_3$/LiF/Al were obtained by in-situ deposition of $Alq_3$, LiF and Al as the electron transport material, electron injection material and cathode, respectively. Green OLEDs fabricated in our experiments showed the color coordinate of CIE(0.29, 0.65) and the maximum power efficiency of 7.3 lm/W at 12 V with the peak emission wavelength of 521 nm.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.1-7
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• 2003

We determined the optical constants of organic light emitting material of Alq$_3$ in a spectral range between 1.5 and 6 eV using the physical model introduced by Forouhi and Bloomer［Phys. Rev. B 34, pp. 7018-7026, 1986.］. The initial parameters of $A_i,\;B_i,\;C_i$ of Forouhi-Bloomer dispersion relations were determined from the absorption peaks and widths of absorption spectra of the Alq$_3$ film. The refractive index of substrate, a fused silica, is derived from the Sellmeier equation with the measured transmittance and reflectance spectra. Then, the complex refractive index and thickness of the Alq$_3$ film were calculated by use of a nonlinear least square fitting program with the Forouhi-Bloomer dispersion relation and the measured transmittance and reflectance spectra.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.241-241
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• 2010

Recently high and persistent spontaneous buildup of a surface potential (SP) upon vacuum deposition of tris (8-hydroxyquinolinato) aluminum (III) ($Alq_3$), which is widely used for organic light emitting devices. The removal of the giant surface potential by visible light irradiation has also been reported. In this study, we coated $Alq_3$ on the FTO substrate and raise the capacity for absorbing sun light. The $Alq_3$ which is green light emitting diode emits light at wavelengths between 500 and 550nm. If we apply one's FTO/$Alq_3$ substrate in one's DSSC, we could get higher energy conversion efficiency because the N719 dye that we used for fabricating the DSSC emits light just at near 540nm. The energy conversion efficiency of approximately 4.8 % at the condition of irradiation of AM 1.5 (100 mW/$cm^2$) simulated sunlight, and the $J_{sc}$ is 12.0 mA/$cm^2$, $V_{oc}$ is 0.71 V, FF is 0.56, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.437-443
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• 2000

In this study several lanthanide complexes such as Eu(TTA)$_3$(Phen), Tb(ACAC)$_3$-(Cl-Phen) were synthesized and the white-light electroluminescence(EL) characteristics of their thin films were investigated where the devices having structures of anode/TPD/Tb(ACAC)$_3$(Cl-Phen)/Eu(TTA)$_3$(Phen)/Alq$_3$or Bebq$_2$/cathode and the low work function metal alloy such as Li:Al was used as the electron injecting electrode(cathode). Device structure of glass substrate/ITO/TPD(30nm)/Tb(ACAC)$_3$(Phen)(30nm)/Eu(TTA)$_3$(Phen)(6nm)/DCM doped Alq$_3$(10nm)/Alq$_3$(20nm)/Li:Al(100nm) was also fabricated and their EL characteristics were investigated where Eu(TTA)$_3$(Phen) and DCM doped Alq$_3$were used as red light-emitting materials. It was found that the turn-on voltage of the device with non-doped Alq$_3$was lower than that of the devices with doped Alq$_3$and the blue and red light emission peaks due to TPD and Eu(TTA)$_3$(Phen) with non-doped Alq$_3$were lower than those with DCM doped Alq$_3$Details on the white-light-emitting characteristics of these device structures were explained by the energy and diagrams of various materials used in these structure where the energy levels of new materials such as ionization potential(IP) and electron affinity(EA) were measured by cyclic voltametric method.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1703-1705
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• 2004

New luminescent material, 6.11-dihydoxy-5.12-naphtacene-dione $Alq_3$ complex($Alq_2$-Ncd), 1.4-dihydoxy-5.8-naphtaquinone $Alq_3$ complex ($Al_2Nq_4$) was synthesized. The $Alq_2-$ Ncd and $Al_2Nq_4$ has big molecular weight and many ${\pi}$-electrons more than widely known $Alq_3$. And extended efforts have been made to obtain high-performance electro luminescent(EL) devices. We used hole transfer layer of powdered TPD to improve hole transfer and characteristics of interface in OLED. This study indicates not only the sterical effect but also some other effects that would be responsible for the change of the emission wavelength. improvement of luminance and etc.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1603-1606
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• 2007

The TPS (Temperature Programmed Sublimation) technology has been developed to monitor the plane evaporation of the organic films and introduced in SID2007, P53.[4] The Alq3 organic film is deposited on various metal surface such as Cu, Ti, Invar, STS to sublimate. The TPS signal confirms that the Alq3 film consists of nano scale film phase and bulk phase on all the metal plates. The sublimation temperature of the Alq3 film was much lower ($130^{\circ}C$) than the vapor temperature ($265^{\circ}$) of the Alq3 powder.