• Current Photovoltaic Research
• /
• v.4 no.1
• /
• pp.12-15
• /
• 2016

Screen printing technique followed by firing has commonly been used as metallization for both laboratory and industrial based solar cells. In the solar cell industry, the firing process is usually conducted in a belt furnace and needs to be optimized for fabricating high efficiency solar cells. The printed-Al layer on the silicon is rapidly heated at over $800^{\circ}C$ which forms a layer of back surface field (BSF) between Si-Al interfaces. The BSF layer forms $p-p^+$ structure on the rear side of cells and lower rear surface recombination velocity (SRV). To have low SRV, deep $p^+$ layer and uniform junction formation are required. In this experiment, firing process was carried out by using conventional tube furnace with $N_2$ gas atmosphere to optimize $V_{oc}$ of laboratory cells. To measure the thickness of BSF layer, selective etching was conducted by using a solution composed of hydrogen fluoride, nitric acid and acetic acid. The $V_{oc}$ and pseudo efficiency were measured by Suns-$V_{oc}$ to compare cell properties with varied firing condition.

• Advances in nano research
• /
• v.2 no.1
• /
• pp.23-56
• /
• 2014

The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.123.1-123.1
• /
• 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 $1.8{\sim}2.0/298/0.5{\mu}m$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.1
• /
• pp.18-21
• /
• 2013

$SiO_2$ layer grown by rapid thermal oxidation and $SiN_x$ layer were used for passivating the surface of n-type silicon solar cell, instead of only $SiN_x$ layer generally used in photovoltaic industry. The rapid thermal oxidation provides the reduction of processing time and avoids bulk life time degradation during the processing. Improvement of 30 mV in Voc and $2.7mA/cm^2$ in Jsc was obtained by applying these two layers. This improvement led to fabrication of a large area ($239cm^2$) n-type solar cell with 17.34% efficiency. Internal quantum efficiency measurement indicates that the improvement comes from the front side passivation, but not the rear side, by using $SiO_2/SiN_x$ stack.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.3
• /
• pp.47-52
• /
• 2017

Solar cell industry requires high technologies to stabilize apparatuses for the wafer manufacturing. Vibrations of squaring & grinding machines are one of the most critical factors for causing residual stresses of ingots, which are the main reasons of the breakage in the following processes such as wire sawing, cleaning, and modularity. In this study, the structure of a squaring & grinding machine has been analyzed through experiments and computer simulations to figure out the ways to suppress the vibrations effectively, and further to minimize the breakage of wafers. The result shows that simple design changes of applying a few ribs can improve the stability of the machine.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.168-169
• /
• 2022

The continuous development of science and technology since the Industrial Revolution and the development of human civilization are based on the use of fossil fuels. However, the use of fossil fuels is increasing the greenhouse gas, the main cause of global warming, and global warming is an extreme climate anomaly that is rapidly increasing human and material damage. Therefore, efforts are being made worldwide to return greenhouse gases to pre-industrial levels. In Korea, 2050 carbon neutrality has been set as a major policy and efforts are being made to curb carbon emissions in the overall industry. Carbon emission suppression is based on the minimization of fossil fuel use, and research and development are underway on building a zero-emission house that minimizes the energy used in buildings in the construction field. Therefore, in this study, as part of the zero-emissions water system construction, waste resources generated at industrial sites were utilized and an integrated lightweight concrete solar panel grafted with a concrete lightweight panel and solar panel was manufactured and the possibility of its use was evaluated.

• Journal of Korean Society for Geospatial Information Science
• /
• v.25 no.1
• /
• pp.71-78
• /
• 2017

Many studies have been implemented to manage solar plant being supplied widely in recent years. This study analyzed heat emission of solar cell using unmanned aerial vehicle(UAV)-based thermal infrared sensor, and major conclusions are as belows. Firstly, orthomosaic image and digital surface model(DSM) data were acquired using UAV-based RGB sensor, and solar light module layer necessary to analyze the heat emission of solar cell was constructed by these data. Also as a result of horizontal error into validation points using virtual reference service(VRS) survey for evaluating the location accuracy of solar light module layer, higher location accuracy could be acquired like standard error of $dx={\pm}2.4cm$ and $dy={\pm}3.2cm$. And this study installed rubber patch to test the heat emission of solar cell and could analyzed efficiently the location of rubber patch being emitted heat using UAV-based thermal infrared sensor. Also standard error showd as ${\pm}3.5%$ in analysis between calculated cell ratio by rubber patch and analyzed cell ratio by UAV-based thermal infrared sensor. Therefore, it could be efficiently analyzed to heat emission of solar cell using UAV-based thermal infrared sensor. Also efficient maintenance of solar plant could be possible through extracting the code of solar light module being emitted of heat automatically.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.298-303
• /
• 2020

This study examined the washing conditions for high-quality solar salt. The salinity of the washing water was set to 5 % to prevent yield loss, and the temperatures of the washing water were 5, 10, 17.5, and 20 ℃. After washing the solar salt, the moisture content, salinity, insoluble matter, and sandy powder were measured from the solar salt. In addition, the color properties, L*[lightness], a*[redness], b*[yellowness], and yield were measured. The moisture content of the salt showed a tendency to increase when the temperature of the washing water was above 10 ℃, and the salinity and yield tended to decrease as the temperature of the washing water was high. The amount of insoluble matter decreased with decreasing temperature of the washing water. In the case of sandy powder, the highest value was 0.67 % at a washing water temperature of 5 ℃, and the value was 0.57 % under the other temperature conditions. Regarding the color properties, the b* [yellowness] of the color of the solar salt increased when the washing water temperature was high. This appeared to decrease the appearance quality. According to the above results, a washing water temperature above 10 ℃ was appropriate. The development of design factors of a high-quality solar salt production system is expected with experiments to define the drying conditions after the washing process.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.3
• /
• pp.81-89
• /
• 2010

The photovoltaic industry is one of the main research areas for regenerable energy usage and green growth policy of the Korean government. R&D programs of MEST(Ministry of Education, Science and Technology) and MKE(Ministry of Knowledge Economy) are concentrating on the development of fundamental and applicable technology which can be carried out by a so-called "Big company" consortium. So it is essential to discover and support R&D projects for small and medium enterprises(SMEs) in the photovoltaic industry. R&D projects should be funded effectively to enhance the competitiveness of the SMEs. It is a complicated process as to decide what R&D projects or key element technologies should be selected and how to support them. In this paper, the supply chain analysis is adopted as a critical tool for selecting the research areas and topics for the SMEs, which can be done by analyzing the number of the SMEs, the level of imports and the localization possibility for each supply chain element. We define the strategic products for the SMEs to deduct core technologies for each strategic product. R&D projects definition sheets are proposed for each core technology. All the decision making processes are authorized by a committee which consists of experts for academia, industries and the research field. The efficacy of the proposed framework is described throughout the photovoltaic industry.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.131-134
• /
• 2001

The three-dimensional precision measurement technology for industry product of middle and/or large scale has been developed. Theodolite measurement system which is one of the technology is widely used in aerospace industry. This paper describes measurement method and results for spacecraft structure test model by using the measurement system. And structural stability for STM is desribed through the comparison between design values and measured values.