• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.766-769
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• 2002

We have seen the effects of hole-injection buffer layer in organic light-emitting diodes using copper phthalocyanine(CuPc), poly(vinylcarbazole)(PVK), and Poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate)(PEDOT:PSS) in a device structure of ITO/buffer/TPD/$Alq_3$/Al. Polymer PVK and PEDOT:PSS buffer layer was made using spin casting method and the CuPc layer was made using thermal evaporation. Current-voltage characteristics, luminance-voltage characteristics and efficiency of device were measured at room temperature with a thickness variation of buffer layer. We have obtained an improvement of the external quantum efficiency by a factor of two, four, and two and half when the CuPc, PVK, and PEDOT:PSS buffer layer are used, respectively. The enhancement of the efficiency is attributed to the improved balance of holes and elelctrons due to the use of hole-injection buffer layer. The CuPc and PEDOT:PSS layer functions as a hole-injection supporter and the PVK layer as a hole-blocking one.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.741-744
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• 2007

The research applied the processes of spin-coating and thermal-evaporating in proper order to deposit the hole transport material N,N'-Bis(naphthalen-1-yl)- N,N'-bis(phenyl)-benzidine (NPB) on the ITO substrate to make flexible organic light emitting diodes (FOLED) with double hole transport layer.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2006년도 제30회 학술논문발표회 초록집
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• pp.139-139
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• 2006

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.165-167
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• 2007

The performance of polymer light emitting diode can be improved significantly by interfacial engineering on anode and/or cathode through adjusting the charge injection barriers for holes and electrons. Studies involve CFx and SAM modifications on ITO, thickness and delay time to baking of PEDOT:PSS, and electron injection/hole blocking layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.53-56
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• 2002

The effect of $\alpha$-septithiophene (${\alpha}-7T$) layers on the organic light emitting diode(OLED) was studied. The ${\alpha}-7T$ was used for a buffer layer in OLED. Hole injection was investigated and improved emission efficiency. The OLEDs structure can be described as indium tin oxide(ITO)/ buffer layer / hole transporting layer / emitting layer / electron transporting layer / LiF / Al. The hole transporting layer were composed of N,N-diphenyl-N,N-di(3-methylphenyl)-1,1-biphenyl-4,4-diamine(TPD), and N,N-di(naphthalene-1-ly)-N,N-diphenyl-benzidine( ${\alpha}$-NPD). The emitting layer, and electron transporting layer consist of tris(8-hydroxyquinolinato) aluminum($Alq_3$). All organic layer were deposited at a background pressure of less than $10^{-6}$ torr using ultra high vacuum (UHV) system. The ${\alpha}-7T$ layer can substitute the hole blocking layer, and improve hole injection properties.

• Journal of Information Display
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• 제4권1호
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• pp.29-33
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• 2003

We have investigated the effects of hole-injection buffer layer in organic light-emitting diodes using copper phthalocyanine (CuPc), poly(vinylcarbazole)(PVK), and Poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) in a device structure of $ITO/bufferr/TPD/Alq_3/Al$. Polymer PVK and PEDOT:PSS buffer layer were produced using the spin casting method where as the CuPc layer was produced using thermal evaporation. Current-voltage characteristics, luminance-voltage characteristics and efficiency of device were measured at room temperature at various a thickness of the buffer layer. We observed an improvement in the external quantum efficiency by a factor of two, four, and two and half when the CuPc, PVK, and PEDOT:PSS buffer layer were used, respectively. The enhancement of the efficiency is assumed to be attributed to the improved balance of holes and elelctrons resulting from the use of hole-injection buffer layer. The CuPc and PEDOT:PSS layer function as a hole-injection supporter and the PVK layer as a hole-blocking one.

• 대한전자공학회논문지
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• 제25권4호
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• pp.422-429
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• 1988

The photoconductive multilayer of Se-As(hole blocking layer)/Se-As-Te (photoconductive layer) /Se-As (layer for supporiting hole transport)/Se-As(layer or controlling total capacitance)/Sb2S3(electron blocking layer) was fabricated and its electrical and optical properties were investigated. The photoconductive multilayer is made of evaporated a-Se as the base material, doped with As and Te to prevent the crystallization of a-Se and to enhance red sensitivity, respectively. The multilayer with good image reproducibility has the following deposition condition. The first layer has the thickness of 250\ulcornerat the deposition rate of 250\ulcornersec. The second layer has the thickness of 800\ulcornerat the deposition rate of 250\ulcornersec. The third layer has the thickness of 125\ulcornerat the deposition rate of 250\ulcornersec. The fourth layer has the thickness of 1700\ulcornerunder the Ar gas ambient of 50x10**-3torr. The image pick-up tube, employing this multilayer demonstrates the following characteristics. The photosensitivity is 0.8, the resolution limit is above 300TV line, and the decay lag is about 7%. And spectral response convers the whole visible range. Therfore the application to color TV camera is expected.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.956-960
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• 2006

Deep-blue organic light-emitting diodes (OLEDs) with/without ultra-thin LiF layer inserted at the interface between hole-blocking and electron-transporting layers have been fabricated and investigated. The fundamental structures of the OLEDs are ITO/m-MTDATA/NPB/BCP/LiF (with/ without)/ $Alq_3/LiF/Al.Deep$ blue light emission with CIE coordinate of (0.15, 0.11) has been achieved for all devices. Further, by inserting LiF with thickness of 1nm at the interface between BCP and $Alq_3$ layer, the luminous efficiency as well as the power efficiency is much improved compared to that without. The enhancement of electron injection due to insertion of LiF may account for this improvement.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.469.2-469.2
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• 2014

All-solid-state solar cell based on Chloride doped organometallic halide perovskite, (CH3NH3)PbIxCl3-x, has achieved a highly power conversion efficiency (PCE) to over 15% [1] and further improvements are expected up to 20% [2]. In this way, solar cells using novel light absorbing perovskite material are actively being studied as a next generation solar cells. However, making solution-process require high temperature up to $500^{\circ}C$ to form compact hole blocking layer and sinter the mesoporous oxide scaffold layer. Because of this high temperature process, fabrication of flexible solar cells on plastic substrate is still troubleshooting. In this study, we fabricated highly efficient flexible perovskite solar cells with PCE in excess of 11%. Atomic layer deposition (ALD) is used to deposit dense $TiO_2$ as hole blocking layer on ITO/PEN substrate. The all fabrication process is done at low temperature below $150^{\circ}C$. This work shows that one of the important blueprint for commercial use of perovskite solar cells.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.780-783
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• 2002

We report very efficient white OLEDs consisting of a blue-emitting 4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}$-NPD), a hole-blocking layer of 2,9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) doped with red fluorescent dye of 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro- 1H, 5H-benzo[i,j]quinolizin-8-yl) vinyl]-4H-pyran) (DCM2), and green-emitting tris(8-hydroxyquinoline) aluminum ($Alq_3$). The device with the structure of ITO/${\alpha}$-NPD (50 nm)/BCP:DCM2 (0.8 %, 4 nm)/$Alq_3$ (50 nm)/LiF (0.5 nm)/Al shows a white emission with the CIE coordinates (0.329, 0.333). The maximum luminance of 20,800 cd/$m^2$ is obtained at 15.4 V. The power efficiency is 2.6lm/W and the external quantum efficiency is 2.1 % at a luminance of 100 cd/$m^2$ at the bias voltage of 6 V.