• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.103-111
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• 2011

Laser drilling of vias is the one of key technologies in developing Emitter-Wrap Through(EWT) solar cell which is particularly attractive due to the use of industrial processing and common solar grade p-type silicon materials. While alternative economically feasible drilling process is not available to date, the processing time and laser induced damage should be as small as possible in this process. This paper provides an overview on various factors that should be considered in using the laser via drilling technology for developing highly efficient and industrially applicable EWT solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.76.1-76.1
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• 2010

Furnace를 이용한 $POCl_3$ 확산 공정은 실리콘 태양전지 제작과정에서 일반적으로 이용되는 에미터 층 형성 공정이다. 하지만, 확산 공정을 통해 P-N Junction을 형성할 경우 전면과 후면의 contact현상이 발생하게 되고 이를 제거하기 위해 Edge isolation 공정을 거치게 된다. 최근에는 레이저로 V 모양의 홈을 형성하는 방법이 이용되고 있다. 본 연구에서는 p-type 실리콘 웨이퍼 기판에 insulating barrier를 형성하여 edge isolation 공정을 없앤 Non-edge isolation공정을 제시한다. Non p-type 실리콘 웨이퍼에 insulating barrier를 형성한다. Insulating barrier가 형성된 BOE용액과 KOH에서의 견딤성 실험을 진행 하였다. 이후, p-type 단결정 실리콘 태양전지의 확산 공정을 진행하여 Non edge isolation 공정을 진행한 경우와 laser를 이용한 edge isolation 공정을 진행한 태양전지를 제작하여 특성을 비교하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.111-113
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• 2009

This paper shows that you can achieve high quality N+ emitter layers using a screen printable phosphorous diffusion paste and firing in an infrared belt furnace. Spreading resistance measurement from a beveled sample is used to measure carrier concentration as a function of depth for different phosphorous concentrations. Contours of estimated sheet resistance are shown for different processing conditions. This paper describes newly developed low cost phosphorous pastes. It shows the characterization of the newly developed phosphorous paste (DP99-038). This low cost pastes can easily be printed and make 16% efficiency.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.792-795
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• 1988

Titanium dioxide antireflection (AR) Coating, which is deposited on Si substrates using an organotitanium solution by the spinning technique, has been studied. The coated films on Si substrates were subsequently heated to $450^{\circ}C$. The thickness and index of refraction of films were varied continuousely from $740{\AA}$ to $1380{\AA}$ and from 1.7 to 2.1 respectively as a function of heat treatment temperature and time. Silicon solar cells AR-coated by the spinning technique showed as much as 31% improvement in conversion efficiency over the uncoated cell.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.6
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• pp.376-379
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• 2016

In this paper, the efficiency improvement of the heterojunction with intrinsic thin layer (HIT) solar cells is obtained by optimization process of p-type a-SiC:H as emitter. The optoelectronic of p-type a-SiC:H layers including the optical band-gap and conductivity under the methane gas content variation is conducted in detail. A significant increase in the Jsc by $1mA/cm^2$ and Voc by 30 mV are attributed to enhanced photon-absorption due to broader band-gap of p-a-SiC:H and reduced band-offsets at p-side interface, respectively of HIT solar cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.351-361
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• 2023

The purpose of this paper is to help those who research and develop solar cells in university laboratories and industrial sites understand the most basic and important quantum efficiency measurement and analysis method in analyzing solar cell performance. Starting with the definition of quantum efficiency, we calculate the theoretical current density according to the band gap of the solar cell material from the solar spectrum, along with a detailed introduction to the measurement and analysis methods, and measure and analyze the theoretical current density and quantum efficiency. We discuss in depth how to analyze the performance of solar cells through Quantum efficiency measurement and analysis of solar cells is a very useful method that can give intuition to solar cell performance analysis as it can analyze solar cells according to depth (front emitter, bulk, rear surface). Students and researchers who study solar cells with a deep understanding of theoretical current density and quantum efficiency measurement analysis are expected to use it as a basis for analyzing solar cell performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.76-82
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• 2013

The solar cell is a device to convert light energy into electric, which supplies power to the external load when exposed to the incident light. The photocurrent and voltage occurred in the device are significant factors to decide the output power of solar cells. The crystalline silicon solar cell module has photocurrent loss due to light reflections on the glass and EVA(Ethylene Vinyl Acetate). These photocurrent loss would be a hinderance for high-efficiency solar cell module. In this paper, the quantitative analysis for the photocurrent losses in the 300-1200 wavelength region was performed. The simulation method with MATLAB was used to analyze the reflection on a front glass and EVA layer. To investigate the intensity of light that reached solar cells in PV(Photovoltaic) module, the reflectance and transmittance of PV modules was calculated using the Fresnel equations. The simulated photocurrent in each wavelength was compared with the output of real solar cells and the manufactured PV module to evaluate the reliability of simulation. As a result of the simulation, We proved that the optical loss largely occurred in wavelengths between 300 and 400 nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.427-427
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• 2016

Organic-inorganic hybrid perovskite have attracted significant attention as a new revolutionary light absorber for photovoltaic device due to its remarkable characteristics such as long charge diffusion lengths (100-1000nm), low recombination rate, and high extinction coefficient. Recently, power conversion efficiency of perovskite solar cell is above 20% that is approached to crystalline silicon solar cells. Planar heterojunction perovskite solar cells have simple device structure and can be fabricated low temperature process due to absence of mesoporous scaffold that should be annealed over 500 oC. However, in the planar structure, controlling perovskite film qualities such as crystallinity and coverage is important for high performances. Those controlling methods in one-step deposition have been reported such as adding additive, solvent-engineering, using anti-solvent, for pin-hole free perovskite layer to reduce shunting paths connecting between electron transport layer and hole transport layer. Here, we studied the effect of alkali metal halide to control the fabrication process of perovskite film. During the morphology determination step, alkali metal halides can affect film morphologies by intercalating with PbI2 layer and reducing $CH3NH3PbI3{\cdot}DMF$ intermediate phase resulting in needle shape morphology. As types of alkali metal ions, the diverse grain sizes of film were observed due to different crystallization rate depending on the size of alkali metal ions. The pin-hole free perovskite film was obtained with this method, and the resulting perovskite solar cells showed higher performance as > 10% of power conversion efficiency in large size perovskite solar cell as $5{\times}5cm$. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectrometry (ICP-OES) are analyzed to prove the mechanism of perovskite film formation with alkali metal halides.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.408.2-409
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• 2016

Theoretically, the dye-sensitized solar cells (DSSCs) are high efficiency solar cells. However DSSCs have low power conversion efficiency (PCE) than silicon based solar cells. In this study, we use the phosphor materials, such as $Y_2O_3:Eu$ (Red), $Zn_2SiO_4:Mn$ (Green), $BaMgAl_{14}O_{23}:Eu$ (Blue), to enhance the PCE of DSSCs. Three phosphors were prepared and used as an effective scattering layer on the transparent $TiO_2$ with doctor blade method. We confirmed that the three scattering layers improve the PCE and Jsc due to the light harvesting enhancement via increased the scattering and absorbance in visible range. Under the sun illumination AM 1.5 conditions, the PCE of the mesoporous $TiO_2$ based DSSCs is 5.18 %. The PCE of the DSSCs with Y2O3:Eu, $Zn_2SiO_4:Mn$ and $BaMgAl_{14}O_{23}:Eu$ as scattering layer were enhanced to 5.66 %, 5.72% and 5.82%, respectably. In order to compare the optical properties change, DSSCs were measured by EQE, reflectance and PCE. At the same time, FE-SEM and XRD were used to confirm the structural changes of each layer.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.78-82
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• 2022

Inorganic-organic hybrid perovskite solar cells have demonstrated considerable improvements, reaching 25.5% of certified power conversion efficiency (PCE) in 2020 from 3.8% in 2009 comparable to silicon photovoltacis. However, there remains important concern on the stability of perovskite solar cells under environmental conditions that should be solved prior to commercialization. In order to overcome the problem, we have introduced a small amount of octylammonium iodide with longer alkyl chain than volatile methylammonium iodide into MAPbI₃ perovskites. The presence of octylammonium into perovskites were confirmed using Fourier-transform infrared spectroscopy and UV-visible spectroscopy. Moreover, octylammonium-modified perovskite solar cells showed a PCE of 16.6% and enhanced moisture stability with an increased contact angle of 72.2° from 57.0°. This work demonstrated the importance of perovskite compositional engineering for improving efficiency and stability.