• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.160-160
• /
• 2016

In this study, we applied the low temperature curing Ag paste to replace PVD System. The electrode formation of low temperature curing Ag paste for silicon Hetero-junction solar cells is important for improving device characteristics such as adhesion, contact resistance, fill factor and conversion efficiency. The low temperature curing Ag paste is composed various additives such as solvent, various organic materials, polymer, and binder. it depends on the curing temperature conditions. The adhesion of the low temperature curing Ag paste was decided by scratch test. The specific contact resistance was measured using the transmission line method. All of the Ag electrodes were experimented at various curing temperatures within the temperature range of $160^{\circ}C-240^{\circ}C$, at $20^{\circ}C$ intervals. The curing time was also changed by varying the conditions of 10-50min. In the optimum curing temperature $200^{\circ}C$ and for 20 min, the measured contact resistance is $19.61m{\Omega}cm^2$. Over temperature $240^{\circ}C$, confirmed bad contact characteristic. We obtained photovoltaic parameter of the industrial size such as Fill Factor (FF), current density (Jsc), open-circuit voltage (Voc) and convert efficiency of up to 76.2%, 38.1 mA/cm2, 646 mV and 18.3%, respectively.

• 한국전기전자재료학회논문지
• /
• 제17권6호
• /
• pp.575-579
• /
• 2004

Package reliability test was conducted to investigate the effect of solder paste composition at BGA Package. It was found that the shape and size of the phase form are affected by the processing parameters. The material have used to fill in the via was Sn/36Pb/2Ag and Sn/0.75Cu type solder paste. Sn/36Pb/2Ag and Sn/0.75Cu paste were fabricated on Tape-BGA substrates by screen printing process, and via ball mount data were characterized with variations of dwell time of 85 seconds at reflow peak temperature at 22$0^{\circ}C$ or 24$0^{\circ}C$. The test condition was MRT 30 $^{\circ}C$/60 %RH/96 HR. Failures formed of a ball-off in solder paste process were observed by using a Optical Microscope and SEM(Scanning Electron Microscope). It was concluded that intermetallic layer growth played important roles in increasing solder fatigue strength for addition of Ag composition. The degradation of shear strength of solder composition is discussed.

• Advances in concrete construction
• /
• 제2권3호
• /
• pp.209-227
• /
• 2014

The use of limestone fines (LF) in mortar and concrete can in certain ways improve performance and thus has become more and more commonplace. However, although LF is generally regarded as a filler, it is up to now not clear how much filling effect it could have and how best the filling effect could be utilized. Herein, the packing density and filling effect of LF were studied by measuring the packing densities of LF, (LF + cement) blends and (LF + cement + fine aggregate) blends under dry and wet conditions, and measuring the performance of mortars made with various amounts of LF added. It was found that the addition of LF would not significantly increase the packing density of (LF + cement) blends but would fill into the paste to increase the paste volume and paste film thickness, and improve the flow spread and strength of mortar.

• 한국전기전자재료학회논문지
• /
• 제32권1호
• /
• pp.53-57
• /
• 2019

Recently, the application field of solar panels is increasing. Accordingly, the demand for flexible devices is also steadily increasing. It is therefore necessary to develop $TiO_2$ paste for low-temperature annealing for flexible DSSC fabrication. In this study, the $TiO_2$ paste for low-temperature annealing with varying molar ratio of titanium isopropoxide (TTIP) was prepared, and DSSC was fabricated and its characteristics were compared. As a result, there was no deformation of the particles on the surface in the SEM data. However, the highest open circuit voltage, short circuit current, and fill factor were measured in the DSSC unit cell prepared by adding 0.5 mol of TTIP to the $TiO_2$ paste, and the highest efficiency was 4.148%.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.336-337
• /
• 2007

The energy conversion characteristics of $TiO_2$ paste of dye-sensitized solar cell (DSSC) was investigated. In the case of DSSC without a binder, the current density increased due to the development of porosity. As for DSSC with a binder, the fill factor increased due to the development of network among the particles. The energy conversion efficiency of 7.2% was obtained due to the porosity and the network as for DSSC with the mixed binder (Vol. 50:50).

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.91.1-91.1
• /
• 2010

There are some methods for increasing efficiency of crystalline silicon solar cells. Among them, It is important to reduce the recombination loss of surface for high efficiency. In order to reduce recombination loss is a way to use the BSF(Back Surface Field). The BSF on the back of the p-type wafer forms a p+layer. so, it is prevented to act electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. therefore, open-circuit-voltage and Fill factor(FF) of solar cells are increased. This paper investigates the formation of rear contact process comparing Aluminum-paste(Al-paste) with Aluminum-Metal(99.9%). It is shown that the Aluminum-Metal provides high conductivity and low contact resistance of $21.35m{\Omega}cm$ using the Vacuum evaporation process but, it is difficult to apply the standard industrial process because high Vacuum is needed and it costs a tremendous amount more than Al-paste. On the other hand, using the Al-paste process by screen printing is simple for formation of metal contact and it is possible to produce the standard industrial process. however, it is lower than Aluminum-Metal(99.9) of conductivity because of including mass glass frit. In this study, contact resistances were measured by 4-point prove. each of contact resistances is $21.35m{\Omega}cm$ of Aluminum-Metal and $0.69m{\Omega}cm$ of Al-paste. and then rear contact have been analyzed by Scanning Electron Microscopy(SEM).

• 한국전기전자재료학회논문지
• /
• 제23권7호
• /
• pp.571-574
• /
• 2010

Surface recombination loss should be reduced for high efficiency of solar cells. To reduce this loss, the BSF (back surface field) is used. The BSF on the back of the p-type wafer forms a p+layer, which prevents the activity of electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. Therefore, the open-circuit-voltage (Voc) and fill factor (FF) of solar cells are increased. This paper investigates the formation of the rear contact process by comparing aluminum-paste (Al-paste) with pure aluminum-metal(99.9%). Under the vacuum evaporation process, pure aluminum-metal(99.9%) provides high conductivity and low contact resistance of $4.2\;m{\Omega}cm$, but It is difficult to apply the standard industrial process to it because high vacuum is needed, and it's more expensive than the commercial equipment. On the other hand, using the Al-paste process by screen printing is simple for the formation of metal contact, and it is possible to produce the standard industrial process. However, Al-paste used in screen printing is lower than the conductivity of pure aluminum-metal(99.9) because of its mass glass frit. In this study, contact resistances were measured by a 4-point probe. The contact resistance of pure aluminum-metal was $4.2\;m{\Omega}cm$ and that of Al-paste was $35.69\;m{\Omega}cm$. Then the rear contact was analyzed by scanning electron microscope (SEM).

• 한국건축시공학회지
• /
• 제12권5호
• /
• pp.510-517
• /
• 2012

This study evaluated the recycling potential of in-site waste soil as pile back filling material (PBFM). We performed experiments to check workability, segregation resistance, bond strength, direct shear stress test, and dynamic load test using in-site waste soil in coastal areas. We found that PBFM showed better performance than general cement paste in terms of workability, segregation resistance, and bond strength. On the other hand, the structural performance of PBFM was slightly lower than that of general cement paste due to the skin friction force of pile by Pile Driving Analyzer and direct shear stress. However, because this type of performance degradation in terms of structure can be improved through the use of piles with larger diameter or by changing the type of pile, considering the economics and environment, we considered that recycling of PBFM has sufficient value.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
• /
• pp.207-208
• /
• 2016

The most important things for the production of recycled aggregates are saving energy, suppressing the generation of by-product fine particles and sustaining the performance of concrete. As solutions, this study proposes this technology of improving the performance of recycled aggregates through forced carbonation.1) It is to stimulate and carbonate the bond paste part that causes the deterioration of recycled aggregates. Particularly, the purpose of this technology is to fill and chemically stabilize pores inside the bond paste, further improving the quality of recycled aggregates with a decreased absorption rate and an enhanced aggregate strength. Ultimately, it is possible to obtain a carbonation model, depending on the paste ratio and particle-size distribution of recycled aggregates. Moreover, by calculating the optimum carbonation period through the verification of this carbonation model, it is possible to examine how much the strength is improved by the reformation of recycled aggregated.

• 한국식품과학회지
• /
• 제26권6호
• /
• pp.733-739
• /
• 1994

저온유통이 불가피하면서도 저장 가능 기간이 짧은 두부, 어묵 및 막걸리의 보존성 향상을 위하여 이들의 부패에 관여하는 균을 순수분리, 이들 균주틀 대상으로 각종 식용 식물의 에탄올 및 물 추출물의 향균 효과를 비교하였다. 두부와 막걸리 변질 관여균 모두에 황백 에탄올 추출물이 확실한 향균 효과틀 보였고 어묵의 경우는 황백, 정향, 오배자, 리기다, 백급 및 적작약 에탄을 추출물이 대상 균주 모두에 뚜렷한 항균성을 보였으며 에탄올 추출물이 물 추출물보다 높은 향균성을 나라내었다. 어묵 변질 관여균 모두는 황백 에란올 추출물의 첨가 농도에 따라 중식 저해를 받았으며 2000 ppm에서는 확실한 중식 저지 현상을 보였고 백급 에탄올 추출물은 한 균주에 대해서만 효과가 뚜렸하였다. 막걸리 변질 관여균은 황백 에탄을 추출물 1000 ppm 이상을 첨가시 2균주에서 뚜렷한 중식 억제 현상을 보였다.