• Journal of the Korean Applied Science and Technology
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• v.16 no.4
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• pp.323-327
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• 1999

A water-soluble conducting polymer (CPP400 Paste) containing a derivative of polythiophene with several dopant was investigated as an anode material for organic electroluminescent devices. The device of ITO/CPP 400 Paste/TPD/$Alq_3$/Li:Al was fabricated, where CPP 400 Paste films were prepared by spin coating and TPD and $Alq_3$, films were prepared by vacuum evaporation. It was found that the turn-on voltage, current density, and luminance of the devices were dependent upon the thickness of CPP 400 Paste film in the Electroluminescent and current-voltage characteristics of the devices. This phenomena were explained by the energy level diagram of the device with the energy levels of the CPP400 Paste obtained by cyclic voltammetric method.

• Journal of Powder Materials
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• v.18 no.5
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• pp.423-429
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• 2011

Thermoelectric-thick films were fabricated by using a screen printing process of n and p-type bismuth-telluride-based pastes. The screen-printed thick films have approximately 30 ${\mu}m$ in thickness and show rough surfaces yielding an empty gap between an electrode and the thick film. The gap might result in an increase of an electrical resistivity of the fabricated thick-film-type thermoelectric module. In this study, we suggest a conductive metal coating onto the surfaces of the screen-printed paste in order to reduce the contact resistance in the module. As a result, the electrical resistivity of the thermoelectric module having a gold coating layer was significantly reduced up to 30% compared to that of a module without any metal coating. This result indicates that an introduction of conductive metal layers is effective to decrease the contact resistivity of a thick-film-typed thermoelectric module processed by screen printing.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.235-240
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• 2000

Screen-printing and doctor blade method were investigated and proposed as an electrode coating process for high power capacitor. CV measured from the amorphous $MnO_2$ electrode prepared by screen-printing shows closer to ideal capacitor characteristics. Specific capacitances calculated from CVs with potential scan rate of 50mV/s were 5.8, 81.8, and 172.0 F/g for electrode thickness of $140{\mu}m,\;24{\mu}m,\; 3{\mu}m$, respectively. Assumed that utilization of active $MnO_2$ in electrode of screen-printing is $100\%$, those were $3.4\%$ in one of paste method and $47.6\%$ in one of doctor blade method. The screen-printing can be good technique to coat thin film on current collector for high power application.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.320-322
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• 2007

A new binder-free $TiO_{2}$ paste was prepared by common ion applying effect, enabling low temperature fabrication required for flexible solar cells. The binder-free and high viscosity $TiO_{2}$ coating solution was produced by adding 7.5% aniline in $TiO_{2}$ colloid solution obtained from the high pressure water-heat response method. The resulting pastes had high level of viscosities proper for optimal coating and thus revealed excellent performances in terms of thickness uniformity and I-V characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.330-334
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• 2013

We developed a package of remote phosphor structure having blue LED chips and phosphors physically separated, and the characteristics were evaluated according to different classifications of phosphor coatings. Remote phosphor was produced by screen printing coating on glass substrate with phosphor content rated paste and heat treatment. After mounting Remote phosphor, which has been classified according to number of coatings, on top of blue LED chips, luminous flux, luminous efficacy, CCT and CRI were measured. The measurement results showed the most suitable characteristics of white LED package as a general light source when the content rate of phosphor in Remote phosphor was 80 wt.% with 3 layers of coatings and thickness over $12{\mu}m$.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.34-39
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• 2011

Screen printing method is a common way to fabricate the crystalline silicon solar cell with low-cost and high-efficiency. The screen printing metallization use silver paste and aluminum paste for front and rear contact, respectively. Especially the rear contact between aluminum and silicon is important to form the back surface filed (Al-BSF) after firing process. BSF plays an important role to reduces the surface recombination due to $p^+$ doping of back surface. However, Al electrode on back surface leads to bow occurring by differences in coefficient of thermal expansion of the aluminum and silicon. In this paper, we studied the properties of mono crystalline silicon solar cell for rear electrode with aluminum and aluminum-boron in order to characterize bow and BSF of each paste. The 156*156 $m^2$ p-type silicon wafers with $200{\mu}m$ thickness and 0.5-3 ${\Omega}\;cm$ resistivity were used after texturing, diffusion, and antireflection coating. The characteristics of solar cells was obtained by measuring vernier callipers, scanning electron microscope and light current-voltage. Solar cells with aluminum paste on the back surface were achieved with $V_{OC}$ = 0.618V, JSC = 35.49$mA/cm^2$, FF(Fill factor) = 78%, Efficiency = 17.13%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.192-193
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• 2006

The wet coating process could easily be made from large area film with printing paste mixed with semiconductor and binder material at room temperature. Semiconductor film fabricated about 25mm thickness was evaluated by field emissions-canning electron microscopy (FE-SEM). X-ray performance data such as dark current, sensitivity and signal to noise ratio (SNR) were evaluated. The $Hgl_2$ semiconductor was shown in much lower dark current than the others, but the best sensitivity. In this paper, reactivity and combination character of semiconductor and binder material that affect electrical and X-ray detection properties would prove out though experimental results.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2005.09a
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.71-73
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• 2005

Ferroelectric PZT heterolayered thick films were fabricated by the alkoxide-based sol-gel method. PZT(20/80) and PZT(80/20) paste were made and alternately screen-printed on the alumina substrates. The coating and drying procedure was repeated 4 times to form the heterolayered thick films. The thickness of the PZT heterolayered thick films was approximately 60 mm. All PZT thick films showed the typical XRD patterns of a perovskite polycrystalline structure. The relative dielectric constant and the dielectric loss of the PZT thick films sintered at $1050^{\circ}C$ were 1382 and 1.90%, respectively. The remanent polarization and coercive field of the PZT thick films sintered at $1050^{\circ}C$ were $14.15{\mu}C/cm^2$ and 19.13kV/cm, respectively.

• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.129-133
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• 2006

Ferroelectric PZT heterolayered thick films were fabricated by the alkoxide-based sol-gel method. PZT(20/80) and PZT(80/20) paste were made and alternately screen-printed on the alumina substrates. The coating and drying procedure was repeated 4 times to form the heterolayered thick films. The thickness of the PZT heterolayered thick films was approximately $60{\mu}m$. All PZT thick films showed the typical XRD patterns of a polycrystalline rhombohedral structure. And in the PZT thick films sintered at $1100^{\circ}C$, the pyrochlore phase was observed due to the evaporation of PbO. The relative dielectric constant and the dielectric loss of the PZT thick films sintered at $1050^{\circ}C$ were 445.2 and 1.90 % at 1 kHz, respectively. The remanent polarization and coercive field of the PZT thick films sintered at $1050^{\circ}C$ were $14.15{\mu}C/cm^2$ and 19.13 kV/cm, respectively.