• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.114-118
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• 2011

Dye-Sensitized Solar Cells(DSSCs) consist of a titanium dioxide($TiO_2$) nano film of the photo electrode, dye molecules on the surface of the $TiO_2$ film, an electrolyte layer and a counter electrode. But two transparent conductive oxide(TCO) substrates are estimated to be about 60[%] of the total cost of the DSSCs. Currently novel TCO-less structures have been investigated in order to reduce the cost. In this study, we suggested a TCO-less DSSCs which has titanium double layer electrodes. Titanium double layer electrodes are formed by electron-beam evaporation method. Analytical instruments such as electrochemical impedance spectroscopy, scanning electron microscope were used to evaluate the TCO-less DSSCs. As a result, the proposed structure decreases energy conversion efficiency and short-circuit current density compared with the conventional DSSCs structure with FTO glass, while internal series impedance of TCO-less DSSCs using titanium double layer electrodes decreases by 27[%]. Consequently, the fill factor is improved by 28[%] more than that of the conventional structure.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.124-131
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• 2005

A GDS (Geomagnetic Depth Sounding) method, one of extremely low-frequency EM methods, has been carried out to examine deep geo-electrical structures of the Korean peninsula. In this study, five additive GDS sites acquired in south-eastern area of the Korea were integrated into twelve previous GDS results. In addition, 3-D MT modeling considering the surrounding seas of the Korean peninsula was performed to evaluate sea effect at each GDS site quantitatively. As a result, Observed real induction arrows was not explained by solely sea effect, two conductive structures that are able to explain differences between observed and calculated induction arrows, was suggested. The first conductive structure is the Imjingang Belt, which is thought as a extension of Quiling-Dabie-sulu continental collision belt. The effects of the Imjingang Belt clearly appear at YIN and ICHN sites. The second one is the HCL (Highly Conductive Layer), which is considered as a conductive anomaly by mantle upwelling generated in back-basin region. The effects of the HCL are also confirmed at KZU, KMT101, 107 sites, in the south-eastern of the Korean peninsula.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.73-79
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• 2018

In this paper, TM(transverse magnetic) scattering problems by a conductive strip grating between a double dielectric layer are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the conductive boundary condition is applied to analysis of the conductive strip. The most normalized reflected powers of the sharp variations in minimum values are scattered in direction of the other angles except incident angle. Generally, in the case of numerical analysis except for reflection and transmission power in free space, as the dielectric constants of the double dielectric layer increases, the reflected power increases and the transmitted power decreases relatively, respectively. The numerical results for the presented structure of this paper having a grounded double dielectric layer are shown in good agreement compared to those of the existing papers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.87-92
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• 2016

In this paper, the solutions of TE(transverse electric) scattering problems by a conductive strip grating over two dielectric layers are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic field. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the conductive boundary condition apply to analysis of conducting strip. The most normalized reflected and transmitted powers having a sharp variations are scattered in direction of the other angles except incident angle. The numerical results for the normalized reflected and transmitted powers are analyzed by according as the width and spacing of conductive strip, incident angles, and the relative permittivity and thickness of the two dielectric layers. To confirm the validity of this paper, the numerical results of presented structure are shown in good agreement compared to those of the existing papers.

• Korean Journal of Materials Research
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• v.28 no.9
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• pp.528-533
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• 2018

In recent years, solar cells based on crystalline silicon(c-Si) have accounted for much of the photovoltaic industry. The recent studies have focused on fabricating c-Si solar modules with low cost and improved efficiency. Among many suggested methods, a photovoltaic module with a shingled structure that is connected to a small cut cell in series is a recent strong candidate for low-cost, high efficiency energy harvesting systems. The shingled structure increases the efficiency compared to the module with 6 inch full cells by minimizing optical and electrical losses. In this study, we propoese a new Conductive Paste (CP) to interconnect cells in a shingled module and compare it with the Electrical Conductive Adhesives (ECA) in the conventional module. Since the CP consists of a compound of tin and bismuth, the module is more economical than the module with ECA, which contains silver. Moreover, the melting point of CP is below $150^{\circ}C$, so the cells can be integrated with decreased thermal-mechanical stress. The output of the shingled PV module connected by CP is the same as that of the module with ECA. In addition, electroluminescence (EL) analysis indicates that the introduction of CP does not provoke additional cracks. Furthermore, the CP soldering connects cells without increasing ohmic losses. Thus, this study confirms that interconnection with CP can integrate cells with reduced cost in shingled c-Si PV modules.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.448-453
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• 2018

PV module protective film plays an important role in protecting the solar cell from external environment by anti-hydrolysis polyester, UV resistance and mechanical properties. The backsheet was manufactured by using Roll-to-Roll dry laminating process. The backsheet structure is composed of 3 layers, which are PE, PET, and Fluorine polymer films. In this study, we have experimented the variation of thermal conductivities depending on MgO inputs 10% to 25% in order to confirm the dependence of the module efficiencies. High thermal conductive backsheet can increase the module output power efficiency because the heat is dissipated by spreading out the internal heat. Long-term environment weatherability tests were conducted for confirming 25 year reliability in the field such as PCT, UV, and power efficiency degradations. As the evaluation result, high thermal conductivity can be effective for increase of power efficiency of solar panel by using thermal conductive MgO masterbatch.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.191-193
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• 2006

YBCO wire has a metal substrate to improve the texture structure and highly conductive layers to increase the cryogenic stability. When AC current flows in the YBCO wire, magnetic field which is generated by the AC current magnetizes the metal substrate and induces the eddy current in the stabilizing layer. To examine the effect of the metal substrate and the conducting layer on the transport current loss of YBCO wire, this paper presents the transport current loss of YBCO wire which has metal substrate and conductive layer. YBCO wire with Ni-W substrate and copper layer were chosen as the model HTS wire for numerical calculation. Finite element method has been used to calculate the transport loss and the results of numerical calculation was compared with analytic calculation suggested by Norris.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.324-324
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• 2006

Nb and Ti were added to 316 stainless steel, and then heat-treatments and surface treatments were performed on the 316 stainless steel and the Nb- and Ti-added alloys. All samples indicated enhanced electrical conductivity after surface treatments, whereas they showed low electrical conductivity before surface treatments due to the existence of non-conductive passive film on the alloy surface. In particular, the Hb- and Ti-added alloys showed remarkable enhancement of electrical conductivity compared to the original alloy, 316 stainless steel. Surface characterization revealed that small carbide particles formed on the alloy surface after surface treatments, while the alloys indicated flat surface structure before surface treatments. $Cr_{23}C_6$ mainly formed on the 316 stainless steel, and NbC and TiC mainly formed on the Nb- and Ti-added alloys, respectively. We attribute the enhanced electrical conductivity after surface treatments to the formation of these carbide particles, possibly acting as a means of electro-conductive channel through the passive film. Furthermore, NbC and TiC are supposed to be more effective carbides than $Cr_{23}C_6$ as electro-conductive channels of stainless steel

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.615-618
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• 2009

In order to apply for transparent conductive oxide(TCO), we deposited ZnO thin film on the glass at room temperature by RF magnetron sputtering method. Deposition conditions for low resistivity were optimized in our previous studies. Under the deposition condition with the RF power of 800 [W]. Sheet resistance and surface roughness of ITO and ZnO thin film were measured by Hall-effect measurement system and AFM, respectively. The sheet resistance of ITO and ZnO thin film were 7.290 [$\Omega$] and 4.882 [$\Omega$], respectively. and surface roughness were 3.634 [nm] and 0.491 [nm], respectively. Green OLED was fabricated with the structure of TPD(400 [$\AA$])/Alq3(600 [$\AA$])/LiF(5 [$\AA$])/Al(1200 [$\AA$]). Turn-on voltage of green OLED applied ITO was 7 [V] and luminance was 7,371 [$cd/m^2$]. And, Turn-on voltage of green OLED applied ZnO was 14 [V] and luminance was 6,332 [$cd/m^2$].

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.09a
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• pp.21-30
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• 2002

According the difference of flex substrate, (reel tape), there are three kind assembly types of LCD driver IC is COG, TCP and COF, respectively. The TCP is the maturest in these types for stability of raw material supply and other specification. And TCP is the major assembly type of LCD driver IC and the huge demand from Taiwan's large TFT LCD panel house since this spring. But due to its package structure and the raw material applied in this package, there is some limitation in fine pitch application of this package type, (TCP). So, COF will be very potential in compact and portable application comparison with TCP in the future. There are three kinds assembly methods in COF, one is ACF by using the anisotropic conductive film to connect the copper lead of tape and gold bump of IC, another is eutectic bonding by using the thermo-pressure to joint the copper lead of tape and gold bump of IC, and last is NCP by using non-conductive paste to adhere the copper lead of tape and gold bump of IC. To have a global realization, this paper will briefly review the status of Taiwan's large TFT panel house, the internal driver IC design house, and the back-end assembly house in the beginning. The different material property of raw material, PI tape is also compared in the paper. The more detail of three kinds of COF assembly method will be described and compared in this paper.