• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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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.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.12a
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• pp.36-37
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• 2004

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.56-56
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• 2004

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.126-127
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• 2013

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.326-330
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• 2010

A laser based needle-free liquid drug injection device has been developed. A laser beam is focused inside the liquid contained in the rubber chamber of micro scale. The focused laser beam causes explosive bubble growth, and the sudden volume increase in a sealed chamber drives a microjet of liquid drug through the micronozzle. The exit diameter of a nozzle is 125 ${\mu}m$ and the injected microjet reaches an average velocity of 264 m/s. This device adds the time-varying feature of microjet to the current state of liquid injection for drug delivery.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2637-2643
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• 2010

In order to develop a new line injection system for spin draw yarn (FD SDY) fibers, the effect of various parameters in extrusion and melt line conditions on the dispersion and distribution of $TiO_2$ particles within FD PET fibers was investigated. As a result, the dispersibility of $TiO_2$ particles in a PET matrix is found to depend on the particle size and its surface characteristics. Surface modification of $TiO_2$ by dimethyl polysiloxane resulted in the improved dispersibility and affinity of $TiO_2$ particles in the PET matrix. Especially, residence time, mixing temperature, and mixing shear rate in the new line injection system under the SDY spinning process were very important parameters to minimize the agglomeration of $TiO_2$ particles. The FD SDY prepared by the new line injection system was superior to those using the polymerization process and the conventional masterbatch chip dosing process in the color-L and color-b values of the fibers.

• Proceedings of the Korean Magnestics Society Conference
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• 2006.11a
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• pp.126-127
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• 2006

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.32-32
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• 2013

Using the Vienna ab initio simulation package (VASP) incorporating van der Waals interaction, we have explored structural, adsorption, and magnetic properties of Ni(111)/BN/Co(111) systems. We have found that both Ni(111) and Co(111) layers shows half metallic state, while the spacer BN layer becomes weak metal for one monolayer (ML) thickness and an insulating barrier for two ML thickness. The half metallic states in both Ni(111) and Co(111) layers are robust because it is unchanged independently on the magnetic coupling of Ni(111) and Co(111). This finding suggests that the Ni(111)/BN/Co(111) systems can be utilized for perfect tunneling magnetoresistance system. Moreover, it can be applied for potential spin injecting into semiconductor in FM/semiconductor system due to the fact that the half metallic state in FM layers at the interface will be unchanged.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.428-428
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• 2013

Red color light emitting diodes were fabricated using CdSe/CdS/ZnS quantum dots (QDs). Patterned indium-tin-oxide (ITO) was used as a transparent anode, and oxygen plasma treatment on a surface of ITO was performed. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was spin coated on the ITO surface as a hole injection layer. Then CdSe/CdS/ZnS QDs was spin coated and thermal treatment was performed for the cross-linking of QDs. TiO2 was coated on the QDs as an electron transport layer, and 150 nm of aluminum cathode was formed using thermal evaporator and shadow mask. The device shows a pure red color emission at 606 nm wavelength. Device characteristics will be presented in detail.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.151.2-151.2
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• 2016

We characterized the n-type organic field-effect transistors (OFETs) with non-conjugated polyelectrolytes (NPEs) interlayers as the electron injection layer. Novel NPEs with various ions (Cl-, Br-, I-) improved the electron mobility from $5.06{\times}10^{-3}$ to $2.10{\times}10^{-2}cm^2V^{-1}s^{-1}$ in OFETs based [6,6]-Phenyl-$C_{61}$-butyric acid methyl ester (PCBM) when $PEIEH^+I^-$ spin-cast from 0.6% solution was deposited onto the PCBM layer. Reduced electron injection barrier (${\phi}_e$) at NPE/metal electrode interface was induced by dipole formation and led to increase the electron injection and transport. These findings are important for understanding how NPEs function in devices, the improvement of device performance, and the design of new materials for use in optoelectronic devices.