• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.75-82
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• 2019

Flexible solar cells have attracted enormous attention in recent years due to their wide applications such as portable batteries, wearable devices, robotics, drones, and airplanes. In particular, the demands of the flexible silicon and compound semiconductor solar cells with high efficiency and high reliability keep increasing. In this study, we fabricated a flexible InGaP/GaAs double-junction solar module. Then, the effects of the wind speed and ambient temperature on the operating temperature of the solar cell were analyzed with the numerical simulation. The temperature distributions of the solar modules were analyzed for three different wind speeds of 0 m/s, 2.5 m/s, and 5 m/s, and two different ambient temperature conditions of 25℃ and 33℃. The flexibility of the flexible solar module was also evaluated with the bending tests and numerical bending simulation. When the wind speed was 0 m/s at 25 ℃, the maximum temperature of the solar cell was reached to be 149.7℃. When the wind speed was increased to 2.5 m/s, the temperature of the solar cell was reduced to 66.2℃. In case of the wind speed of 5 m/s, the temperature of the solar cell dropped sharply to 48.3℃. Ambient temperature also influenced the operating temperature of the solar cell. When the ambient temperature increased to 33℃ at 2.5 m/s, the temperature of the solar cell slightly increased to 74.2℃ indicating that the most important parameter affecting the temperature of the solar cell was heat dissipation due to wind speed. Since the maximum temperatures of the solar cell are lower than the glass transition temperatures of the materials used, the chances of thermal deformation and degradation of the module will be very low. The flexible solar module can be bent to a bending radius of 7 mm showing relatively good bending capability. Neutral plane analysis was also indicated that the flexibility of the solar module can be further improved by locating the solar cell in the neutral plane.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.41-47
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• 2016

Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.299-301
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• 2007

An organic-inorganic hybrid solar cell fibers with characteristics such as formability, low-cost and tailorability was developed by deposition of C60 and CuPc on fiber surface. In spite of some variation according to the temperature of ITO deposition, the maximum open circuit voltage of 0.39V was attained at $150^{\circ}C$(1000end). The resulting solar cell showed the performances Isc=0.482, Voc=0.320, FF=0.285 ${\eta}_{e}=0.044$% which are comparable to one of other types of solar cells in literature.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.233-233
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• 2007

• Journal of the Korean Electrochemical Society
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• v.18 no.2
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• pp.86-94
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• 2015

In order to solve incoming environmental crisis and an energy crunch caused by the consumption of fossil fuels, lots of investigations and developments for solar cell application are getting a spotlight in various aspects. Amongst many solar cells, a flexible dye sensitized solar cell is an attractive research field from fundamentals to commercialization. In this manuscript, we introduce materials and available techniques for the future scientific research and technical developments in commercialization.

• Current Photovoltaic Research
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• v.2 no.2
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• pp.73-77
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• 2014

To investigate the effect of metal back-reflective layers (MBLs) on the performance of GaAs solar cells, we fabricated GaAs solar cells on Al and Ag metal layers using the transfer printing technique. We also investigated the effect of MBL texturing on the performance of transfer printed GaAs solar cells. Transfer printed solar cells with MBLs exhibited improved photovoltaic performance compared to solar cells without MBLs due to light trapping. We demonstrated GaAs solar cells with MBLs on a flexible substrate and performed systematic bending tests. All the measured characteristics of solar cells showed little change in performance.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.153-155
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• 2009

In this study, we fabricated the $Cu(In,Ga)Se_2$ (CIGS) thin-film solar cells by using a polyimide substrate. The CIGS thin-film was deposited on Mo coated polyimide substrate by a 3-stage co-evaporation technique. Because the polyimide shows thermal transformation at about $400^{\circ}C$, the substrate temperature of co-evaporation process was set to below $400^{\circ}C$. Corresponding solar cell showed a conversion efficiency of 7.08 % with $V_{OC}$ of 0.58 V, $J_{SC}$ of 24.99 $mA/cm^2$ and FF of 0.49.

• Journal of the Korean institute of surface engineering
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• v.48 no.1
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• pp.23-26
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• 2015

What causes the transformation of a solar cell is the behavior difference of thermal expansion occurred between the substrate and the layer of semiconductor used in the solar cell. Therefore, the substrate has to possess a behavior of thermal expansion that is similar with that of semiconductor layer. This study employed electroforming to manufacture Fe-Ni alloy materials of different compositions. To verify the result from a finite element analysis, a two-dimensional Mo substrate was calculated and its verification experiment was conducted. The absolute values from the finite element analysis of Mo/substrate structure and its verification experiment showed a difference. However, the size of residual stress of individual substrate compositions had a similar tendency. Two-dimensional CIGS/Mo/$SiO_2$/substrate was modeled. Looking into the residual stress of CIGS layer occurred while the temperature declined from $550^{\circ}C$ to room temperature, the smallest residual stress was found with the use of Fe-52 wt%Ni substrate material.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.123.1-123.1
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• 2017

Hybrid solar cells have intensively studied in recent years due to their advantages such as cost effectiveness and possibility of applications in flexible and transparent devices. It is critical to fabricate individual layer composed of organic and inorganic materials in the hybrid solar cell at low cost. Therefore, it is required to manufacture cheaply and enhance the photon-to-electricity conversion efficiency of each layer in the flexible solar cell industry. In this research, we fabricated pure Cu metal mesh electrode prepared by using electroplating and/or electroless plating on the Ni mold which was manufacture through photolithography, electroforming, and polishing process. Copper mesh was formed on the surface of nickel metal working master when pulsed electrolytic copper deposition were performed at various plating parameters such as plating time, current density, and so on. After electrodeposition at 2ASD for 5~30seconds, the line/pitch/thickness of copper mesh sheet was $1.8{\sim}2.0/298/0.5{\mu}m$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.585-586
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• 2012