• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.918-921
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• 2010

We have proposed an dielectric layer to improve the luminance of red organic light emitting device. Here, we have calculated refractive index of dielectric layer material that was revised refractive index of organic material, ITO and glass. Refractive index of dielectric layer material was 1.711. The structure of dielectric layer was designed in organic material/ITO/dielectric layer/glass. Dielectric material changed thickness that deposited by ion-assisted deposition system. Transmittances of ITO were 95.66-98.85 [%]. Red OLED was fabricated with the structure of TPD($400[{\AA}]$)/DCMII($20[{\AA}]$), Rubrene($20[{\AA}]$)/Alq3($500[{\AA}]$)/LiF($15[{\AA}]$)/Al($1,000[{\AA}]$). Turn-on voltage and Luminance of Red OLED were 10 [V] and 5,857 cd/m2.

• Journal of Photoscience
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• v.11 no.32
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• pp.77-81
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• 2004

Deoxygadusol (DO) and structurally related mycosporine-like amino acids, i.e. mycosporine glycine (MO) and mycosporine taurine (MT), were isolated from phytoplankton Prorocentrum micans and studied for the reactivity toward singlet oxygen. These water-soluble compounds with a cyclohexenone chromophore were all shown to be highly effective in quenching singlet oxygen ($^1$ $O_2$), with the efficiencies being significantly larger compared with histidine, a well-known $^1$ $O_2$ quencher. The $^1$ $O_2$ reaction rate constant ( $k_{Q}$) of DG was determined to be 5.4 ${\times}$ 10$^{7}$ $M^{-1}$ $s^{-1}$ by a steady state method based on competitive inhibition of rubrene oxidation. The feasibility of this method was confirmed by estimating the $k_{Q}$ values for MG and two other quenchers, furfuryl alcohol and 1,4-diazabicyclo [2,2,2]octane, and comparing with those values determined by the time-resolved $^1$ $O_2$ decay method in the previous work.ork.

• Journal of Information Display
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• v.11 no.3
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• pp.123-127
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• 2010

Fluorescent white organic light-emitting diodes showing high color-rendering indices (CRIs) of up to 81 was demonstrated, with a silicon-cored anthracene derivative (PATSPA) doped with DPAVBi utilized as the deep-blue host and dye materials, and the commercial dyes rubrene and DCM2 utilized as the orange- and red-light-emitting dyes. The devices, consisting of three emissive layers, showed bright-white-light emission, but the ratio of the blue peak to the orange and red peaks changed with the current density and the thickness of the blue emissive layer. A high CRI was achieved with the use of a deep-blue emitter doped in a novel host and by optimizing the blue-layer thickness. The device with a blue-layer thickness of 10 nm showed the Commission Internationale de l'Eclairage (CIE) color coordinate of (0.33, 0.35), a high CRI of 81, and a moderate external quantum efficiency of 2% at a current density of $2.5\;mA/cm^2$.

• Journal of Information Display
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• v.3 no.2
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• pp.6-12
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• 2002

In order to achieve white emission from organic light emitting devices (OLEDs), five distinct structures were fabricated and tested. The white emission was obtained using two different color-emitting materials (yellow from rubrene-doped $Alq_3$ and blue from DPVBi) with or without a carrier-blocking layer. For enhancing the red emission, two types of devices with three-color emitting materials were fabricated. The white emission, close to the CIE coordinate of (0.3,0.3), was achieved by using two blocking layers as well that as without a blocking layer. This paper covers the subject of controlling the location of exciton recombination zone. It has been found that there is a trade-off in that the devices with three color emitting layers do not show as much luminescence efficiency compared to those with two color emitting layers, but rather, show distinct red emission in the resultant emission spectra. The highest power efficiency was measured to be 1.15lm/W at 2,000 $cd/m^2$ for a structure with two color-emitting layers.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2299-2302
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• 2009

By controlling the number of electrons transferred to the emitting layer, highly efficient three-wavelength WOLEDs were fabricated. Such WOLEDs are different from those made using simple stacking of RGB emitting layers in that the movement distribution of electrons transferred to emitting layer could be adjusted using the difference in LUMO energy level and that lights of all 3 wavelengths could be emitted through appropriate arrangement of RGB emitting layers. WOLED device with the structure of m-MTDTA (40 nm)/NPB (10 nm)/ Coumarin6 doped $Alq_3$ (3%) (8 nm)/ Rubrene doped NPB (5%) (15 nm)/NPB (2 nm)/ DPVBi (20 nm)/$Alq_3$ (20 nm)/LiF (1 nm)/Al (200 nm) showed high luminance efficiency of 8.9 cd/A and color purity of (0.31, 0.40). In addition, WOLED device with the thickness of non-doped NPB layer increased from 2 nm to 3 nm to increase blue light emission showed a luminance efficiency of 7.6 cd/A and color purity of (0.28, 0.36).

• Journal of the Korean institute of surface engineering
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• v.46 no.3
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• pp.111-115
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• 2013

To study the encapsulation method for large-area organic light emitting devices (OLEDs), OLED of ITO / 2-TNATA / NPB / $Alq_3$:Rubrene / $Alq_3$ / LiF / Al structure was fabricated, which on $Alq_3$/LiF/Al as protective layer of OLED was deposited to protect the damage of OLED, and subsequently it was encapsulated using attaching film and flat glass. The current density and luminance of encapsulated OLED using attaching film and flat glass has similar characteristics compared with non-encapsulated OLED when thickness of Al as a protective layer was 1200 nm, otherwise power efficiency of encapsulated OLED was better than non-encapsulated OLED. Encapsulation process using attaching film and flat glass did not have any effects on the emission spectrum and the Commission International de L'Eclairage (CIE) coordinate. The lifetime of encapsulated OLED using attaching film and flat glass was 287 hours in 1200 nm Al thickness, which was increased according to thickness of Al protective layer, and was improved 54% compared with 186 hours in same Al thickness, lifetime of encapsulated OLED using epoxy and flat glass. As a result, it showed the improved efficiency and the long lifetime, because the encapsulation method using attaching film and flat glass could minimize the impact on OLED caused through UV hardening process in case of glass encapsulation using epoxy.

• Journal of the Korean institute of surface engineering
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• v.47 no.3
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• pp.99-103
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• 2014

The encapsulation method of flexible organic light emitting devices (OLEDs) was investigated for the structure of ITO / 2-TNATA / NPB / $Alq_3$ : Rubrene (1 vol.%) / $Alq_3$ / LiF / Al / $Alq_3$ / LiF / Al (OLED #1), on which $SiN_x$ thin film was deposited and metal film was attached to protect the damage of OLED from oxygen and moisture. The $SiN_x$ thin film was deposited by plasma enhanced chemical vapor deposition (PECVD) method using $SiH_4$ of 20 sccm and $N_2$ of 15~35 sccm as reactor gases. The optimum $SiN_x$ deposition condition was found to be 20 sccm $SiH_4$ and 20 sccm $N_2$ from the Ca test of the fabricated $SiN_x$ thin film. The life time of OLED #1, OLED #1 / $SiN_x$ 200 nm, OLED #1 / $SiN_x$ 400 nm and OLED #1 / $SiN_x$ 400 nm / metal film was 7, 12, 25, and 45 hours, respectively. In conclusion, it has been shown that the lifetime of OLEDs can be improved more than 6 times by $SiN_x$ film and a metal film encapsulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.9
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• pp.581-586
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• 2015

We studied optical and electrical properties of two-wavelength white tandem organic light-emitting diodes using red and blue materials. White fluorescent OLEDs were fabricated using Alq3 : Rubrene (3 vol.% 5 nm) / SH-1 : BD-2 (3 vol.% 25 nm) as emitting layer (EML). White single fluorescent OLED showed maximum current efficiency of 9.7 cd/A, and tandem fluorescent OLED showed 18.2 cd/A. Commission Internationale de l'Eclairage (CIE) coordinates of single and tandem fluorescent OLEDs was (0.385, 0.435), (0.442, 0.473) at $1,000cd/m^2$, respectively. White hybrid OLEDs were fabricated using SH-1 : BD-2 (3 vol.% 10 nm) / CBP : $Ir(mphmq)_2(acac)$ (2 vol.% 20 nm) as EML. White single hybrid OLED showed maximum current efficiency of 7.8 cd/A, and tandem hybrid OLED showed 26.4 cd/A. Maximum current efficiency of tandem hybrid OLED was more twice as high as single OLED. CIE coordinates of single hybrid OLED was (0.315, 0.333), and tandem hybrid OLED was (0.448, 0.363) at $1,000cd/m^2$. CIE coordinates in white tandem OLEDs compared to those for single OLEDs observed red shift. This work reveals that stacked white OLED showed current efficiency improvement and red shifted emission than single OLED.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.539-544
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• 2013

To study the encapsulation method for heat dissipation of high brightness organic light emitting diode (OLED), red emitting OLED of ITO (150 nm) / 2-TNATA (50 nm) / NPB (30 nm) / $Alq_3$ : 1 vol.% Rubrene (30 nm) / $Alq_3$ (30 nm) / LiF (0.7 nm) / Al (200 nm) structure was fabricated, which on $Alq_3$ (150 nm) / LiF (150 nm) as buffer layer and Al as protective layer was deposited to protect the damage of OLED, and subsequently it was encapsulated using attaching film and metal sheet. The current density, luminance and power efficiency was improved according to thickness of Al protective layer. The emission spectrum and the Commission International de L'Eclairage (CIE) coordinate did not have any effects on encapsulation process using attaching film and metal sheet The lifetime of encapsulated OLED using attaching film and metal sheet was 307 hours in 1,200 nm Al thickness, which was increased according to thickness of Al protective layer, and was improved 7% compared with 287 hours, lifetime of encapsulated OLED using attaching film and flat glass. As a result, it showed the improved current density, luminance, power efficiency and the long lifetime, because the encapsulation method using attaching film and metal sheet could radiate the heat on OLED effectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.691-700
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• 2006

Based on the destination IP address of incoming packets, the Internet routers determine next hops and forward packets toward final destinations through If address lookup. The bandwidth of communication links increases exponentially fast as well as the routing table size grows significant as the number of single host networks attached to the Internet increases. Since packets should be processed at wire-speed, the increased link speed reduces the processing time of a packet in routers, and hence more efficient and fast IP address lookup algorithms and architectures are required in the next generation routers. Most of the previous IP lookup schemes compare routing prefixes of shorter length first with a given input IP address. Since IP address lookup needs to find the most specific route of the given input, search continues until the longest matched prefix is found while it keeps remembering the current test matching prefix. In this paper, based on binary search on prefix length, we proposed a new IP address lookup algorithm which compares longer prefixes first. The proposed scheme is consisted of multiple tries with prefixes on leaves only. The trie composed of the longest prefixes is primarily searched whether there is a match with the given input. This processing is repeated for the trio of the next longer prefixes until there finds a match. Hence the proposed algorithm provides the fast search speed. The proposed algorithm also provides the incremental update of prefixes while the previous binary search on length scheme does not provide the incremental update because of pre-processing requirement. In this paper, we performed extensive simulations and showed the performance comparisons with related works.