• Current Photovoltaic Research
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• v.2 no.4
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• pp.173-176
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• 2014

We have investigated the seed layer formation of front side contact using the inkjet printing process. Conductive silver ink was printed on textured Si wafers with 80 nm thick $SiN_x$ anti reflection coating (ARC) layers and thickened by light induced plating (LIP). The inkjet printable sliver inks were specifically formulated for inkjet printing on these substrates. Also, a novel method to prepare nano-sized glass frits by the sol-gel process with particle sizes around 5 nm is presented. Furthermore, dispersion stability of the formulated ink was measured using a Turbiscan. By implementing these glass frits, it was found that a continuous and uniform seed layer with a line width of $40{\mu}m$ could be formed by a inkjet printing process. We also investigated the contact resistance between the front contact and emitter using the transfer length model (TLM). On an emitter with the sheet resistance of $60{\Omega}/sq$, a specific contact resistance (${\rho}_c$) below $10m{\Omega}{\cdot}cm^2$ could be achieved at a peak firing temperature around $700^{\circ}C$. In addition, the correlation between the contact resistance and interface microstructures were studied using scanning electron microscopy (SEM). We found that the added glass particles act as a very effective fire through agent, and Ag crystallites are formed along the interface glass layer.

• Korean Journal of Materials Research
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• v.22 no.8
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• pp.390-396
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• 2012

Ag pastes added to Bi-oxide frits have been applied to the electrode material of Si solar cells. It has been reported that frits induce contacts between the Ag electrodes and the Si wafer after firing. During firing, the control of interfaces among Ag, the glass layer, and Si is one of the key factors for improving cell performance. Specifically, the thermo-physical properties of frits considerably influence Ag-Si contact. Therefore, the thermal properties of frits should be carefully controlled to enhance the efficiency of cells. In this study, the interface structures among Ag electrodes, glass layers, and recrystallites on an $n^+$ emitter were carefully analyzed with the thermal properties of lead-free frits. First, a cross-section of the area between the Ag electrodes and the Si wafer was studied in order to understand the interface structures in light of the thermal properties of the frits. The depth and area of the pits formed in the Si wafer were quantitatively calculated with the thermal properties of frits. The area of the glass layers between the Ag electrodes and Si, and the distribution of recrystallites on the $n^+$ emitter, were measured from a macroscopic point of view with the characteristics of the frits. Our studies suggest that the thermophysical properties should be controlled for the optimal performance of Si solar cells; our studies also show why cell performance deteriorated due to the high viscosity of frits in Ag pastes.

• Polymer(Korea)
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• v.29 no.5
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• pp.486-492
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• 2005

Into a no-conjugated polymer chain we have introduced side chains with a styrene-linked triphenylamine segment as a $\pi-electron$ donor, styrene-]inked aminobenzaldehyde segment as a tunable reactive -CHO group, and PM (4-(dicyanomethylene)-2-(tert-butyl)-4H-pyran) moiety as a $\pi-electron$ acceptor for red emitting materials. The thermal stability and the optical properties of the statistical copolymers have been studied. All the polymers were electrochemically active and showed electroluminescent emission at around 700nm. The EL device of P5-PM based on the sturcture of $ITO/PPV/polymer/BCP/Alq_3/Al$ showed a maximum brightness of $120cd/m^2\;at\;50mA/cm^2$ with an external quantum efficiency of $0.67\%$. It was possible to enhance the external quantum efficiency by balancing the charge recombination. A red-emitting polymer with high external quantum efficiency was developed by incorporating bifunctionality.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.1
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• pp.65-73
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• 1999

Si-tip FEAs were fabricated by a lift-off based process and their operating properties were evaluated. The dependence of emission current on applied gate and anode voltages, maximum emission current, hysteresis phenomena, MOSFET-type curves, current fluctuation, light emission from the emitted electrons, and failure mechanism of the device were widely discussed based on the experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.927-930
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• 2004

We report on a new type of a flat and thin display with a secondary emission electron source. In this display device electrons are multiplied between two secondary emission plates under a high frequency electric field. This principle has a few important advantages over a field emission display: the emission comes from flat plates, which reduces the life-time problems of ion bombardment of field emitter tips. Furthermore, the electron emission is space charge limited which gives a uniform electron distribution. The electrons are extracted from the source and accelerated to a phosphor screen to generate light. Gray levels are made by pulse width modulation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.12.1-12.1
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• 2011

최근 p-type 결정질 실리콘 태양전지의 광열화현상(light induced degradation)에 대한 관심이 높아지면서, 이를 해결하기 위한 많은 연구들이 수행되고 있다. 본 연구에서는 LID 현상을 원천적으로 제거 할수 있는 n-type 기판을 이용하여, 상업적으로 양산화 가능한 공정을 도입하고, 시뮬레이션을 통하여 고효율화 방안을 제시하고자 한다. 이를 위해 일반적인 p-type 결정질 실리콘 태양전지 제작 공정을 사용하여 알루미늄이 도핑된 후면 에미터 구조의 n-type 결정질 실리콘 태양전지를 제작하였으며, PC1D 시뮬레이션을 통해서 n+/n/p+구조의 n-type 결정질 실리콘 태양전지의 에너지 변환 효율 향상을 위한 방안을 제시하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1433-1436
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• 2007

Using a blue emitting DPVBi material and red dopant DCJTB, WOLEDs with and without green emitter C6 added in ETL or HTL have been fabricated. The chromaticity color index of WOLEDs without C6 depends strongly on the doping concentration. In addition, manipulating thickness of emitting layer is similar effect such as controlling weight concentration of dopant. While the white color of WOLEDs with C6 added in ETL or HTL depend on position of C6. WOLED of three colors added green dye have been shown turn-on voltage of 3.25V, and EL efficiency 3.05cd/A @9V, $8102\;cd/m^2$, CIE coordinates (0.30, 0.32).

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.644-647
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• 1996

In this study the theoretical minimum resolution analysis of an active vision system using laser range finder is performed for surrounding recognition and 3D data acquisition in unknown environment. The laser range finder consists of a slitted laser beam generator, a scanning mechanism, CCD camera, and a signal processing unit. A laser beam from laser source is slitted by a set of cylindrical lenses and the slitted laser beam is emitted up and down and rotates by the scanning mechanism. The image of laser beam reflected on the surface of an object is engraved on the CCD array. In the result, the resolution of range data in laser range finder is depend on distance between lens center of CCD camera and light emitter, view and beam angles, and parameters of CCD camera.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1275-1278
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• 2003

This research describes a image-processing technique for the scratch detecting algorithm for ITO coated glass. The light emitter efficiency of Organic EL has a failing-off in quality due to many causes. One of the many causes was the defects of the surface in ITO coated glass. We use the logical level thresholding method for binarization of gray-scaled glass image. This method is useful to the algorithm for detecting scratch of ITO coated glass automatically without need of any prior information of manual fine tuning of parameters.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.7-10
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• 2016

The post cleaning method for clean the shadow mask using in OLED (organic light emitting diode) emitter layer is always reforming. The cleaning solution and analysis method of shadow mask is still lack and not optimized. We use the simple and useful analytical method to determine the quantity and quality of organic and inorganic residue on surface of shadow mask. Finally analyze the cleaning solution using Raman spectroscopy efficiently.