• 한국전기전자재료학회논문지
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• 제15권2호
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• pp.110-118
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• 2002

Organic thin film transitors(OTFT) are of interest for use in broad area electronic applications. And recently organic electroluminescent devices(OELD) have been intensively investigated for using in full-color flat-panel display. We have fabricated inverted-staggered structure OTFTs at lower temperature using the fused-ring polycyclic aromatic hydrocarbon pentacene as the active eletronic material and photoacryl as the organic gate insulator. The field effect mobility is 0.039∼0.17 ㎠/Vs, on-off current ratio is 10$\^$6/, and threshold voltage is -7V. And here we report the study of driving emitting, Ir(ppy)$_3$, phosphorescent OELD with all organic thin film transistor and investigated its electrical characteristics. The OELD with a structure of ITO/TPD/8% Ir(ooy)$_3$ doped in BCP/BCP/Alq$_3$/Li:Al/Al and OTFT with a structure of inverted-stagged Al(gate electrode)/photoacry(gate insulator)/pentacene(p-type organic semiconductor)/ Au(source-drain electrode) were fabricated on the ITP patterned glass substrate. The electrical characteristics are turn-on voltage of -10V, and maximum luminance of about 90 cd/㎡. Device characteristics were quite different with that of only OELD.

• 대한화학회지
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• 제54권6호
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• pp.711-716
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• 2010

비닐렌기에 플루오르 치환기를 도입한 새로운 전자발광 (EL) 고분자인 poly(m-silylphenyl-p-phenylene-difluorovinylene) (m-SiP-PPDFV)는 GILCH polymerization 방법에 의해 합성된다. 이들 고분자는 단층 구조 (ITO/PEDOT/polymer/Ca:Al)의 light-emitting diodes (LEDs)에서 EL 발광층으로 사용되었다. m-SiP-PPDFV는 $\lambda_{max}$ = 452 nm 주위에서 PL 발광파장을 나타내었고, $\lambda_{max}$ = 497 nm 주위에서 녹색의 EL 발광을 나타내었다. 고분자의 current-voltage-luminance (I-V-L) 특성에서는 4.0 V 정도에서부터 소자가 작동되기 시작하였다. 고분자의 전자 친화도를 증가시키는 m-SiP-PPDFV을 얻기 위해 m-SiP-PPV의 모든 비닐렌기에 두개의 플루오르기를 도입하였고, 이로 인하여 소자 구동에서 비닐렌기의 색 안정도를 나타냈었다. PPV 유도체들에서 일어나는 비닐렌기의 산화반응을 보호하는 플루오르기는 전자 끄는 효과를 가지고 있어 소자의 색 안정도를 유지시킨다. 이번 연구로, 보다 안정화된 PPV 유도체를 얻기 위해, 플루오르기가 비닐렌기에 도입될 수 있음을 보여주고 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1007-1010
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• 2003

We made use of $Alq_3$ which is the representative light-emitting material. Electric conduction mechanism and luminance characteristics were analyzed in this paper. We have also measured current density-thickness-voltage characteristics with thickness variation from 60 to 400nm. we analyzed the low electric and the high electric field in theoretically. Also, maximum luminous efficiency is the thickness 200 nm of $Alq_3$ in luminous-thickness characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1581-1583
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• 2000

In this paper, we proposed a surface discharge FFL with the new electrode structure like the needle shaped electrode as the variation of cell structure to high luminance and low power consumption. In comparison with different electrode structure it has low discharge voltage and current and good optical characteristics. So it has better discharge characteristics than different surface discharge FFL and can be fungible of backlight as a lighting source in LCDs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.305-306
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• 2009

In this study, we have invastigated the recombination zone in the blue phosphorescent organic light-emitting devices with various partially doped structures. The basic device structure of the blue PHOLED was anode / hole injection layer (HIL) / hole transport layer (HTL) / emittingvastigated the recombination zone in the blue layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) / cathode. After the preparation of the blue PHOLED, the current density (J) - voltage (V) - luminance (L) and current efficiency characteristics were measured.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.913-916
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• 2006

The improvement of luminous efficacy is one of the major issues in PDP industry. In this work, we propose the new driving method for high efficiency AC-PDP and analyze its discharge characteristics. The suggested method can control the effective capacitance of panel by external auxiliary capacitor. External capacitor induces reduction of gap voltage proportional to the panel current, this in turn modifies the transient behaviour of discharge. The peak current level is reduced and the discharge duration is increased. As a result of these modifications, the luminous efficacy is enhanced by about 200% compared with the conventional driving method

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.155-155
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• 2010

We have investigated organic light-emitting devices by doping phosphorescent orange and fluorescent blue emitters into the separate layers of single host. The electroluminescence spectra and current efficiency were strongly dependent on the location of each doped layers. The luminance-voltage (L-V) characteristics of the device2 (ITO/Hole Transport Layer/Orange Phosphorescent emissive layer/Blue Fluorescent emissive layer/Electron Transport Layer/liF/Al) showed the maximum current efficiency of 19.5 cd/A.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.956-960
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• 2009

The characteristics of organic films can be affected by the temperature of evaporation source because the temperature of evaporation source has an effect on substrate temperature during OLED fabrication process using the thermal evaporation. To investigate the characteristics of OLED devices fabricated by using thermally damaged organic films, I-V-L and half life-time in OLED devices fabricated with various substrate temperatures were measured. During emission layer(EML) evaporation, OLED devices with a structure of ITO(100 nm)/ELM200(50 nm)/NPB(30 nm)/$Alq_3$(55 nm)/LiF(0.7 nm)/Al(100 nm) were fabricated at various substrate temperatures(room temperature, $30^{\circ}C$, $40^{\circ}C$, and $50^{\circ}C$). The characteristics of current density and luminance versus applied voltage in OLED devices fabricated shows that many electrical currents flowed and high brightness appeared at low voltage, but that the lifetime of OLED devices dropped suddenly. This phenomenon explained that the crystallization of $Alq_3$ thin film appeared owing to the substrate heating during evaporation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.447-450
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• 2003

In this paper, new luminescent material, 6,11-dihydoxy-5,12-naphtacene-dione Alq3 complex (Alq2-Ncd), 1,4-dihydoxy-5,8-naphtaquinone Alq3 complex(Alq2-Nq) was synthesized. And extended efforts had been made to obtain high-performance electroluminescent(EL) devices, since the first report of organic light-emitting diodes(OLEDS) based on tris-(8-hydroxyquinoline) aluminum(Alq3). We have performed investigate characterization of the materials. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured by Flat Panel Display Analysis System(Model 200-AT) at room temperature. An intensive research is going on to improve the device efficiency using the hole injection layer, different electrodes, and etc. By using the hole injection layer, the charge-injection can be controlled and the stability could be improved. This study indicates not only the sterical effect but also some other effects would be responsible for the change of the emission wavelength.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1588-1590
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• 2001

The voltage controlled ramp waveform(VCR) has recently been used in the reset period prior to addressing for plasma display. However, in this paper, the current controlled ramp waveform(CCR) which may prevent the oscillation of gap voltage cause current growth and decrease the background luminance has been suggested. As a result, in case of CCR method, the contrast ratio was about 14% increased compared with VCR method, whereas the addressing and sustainin discharge characteristics of CCR method were same with those of VCR method.