• 신재생에너지
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• 제4권2호
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• pp.74-80
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.390-393
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.

• 한국진공학회지
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• 제16권3호
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• pp.172-180
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• 2007

외부전극 형광램프(EEFL)에서 빛의 방출 전파 신호의 관측법에 의하여 플라즈마의 전자 온도와 밀도를 진단하는 새로운 방법을 소개한다. 직경 4.0 mm이고 램프 길이 860 mm인 37인치 LCD-TV용 외부전극 형광램프에 대하여, 전압 인가 방식에 따른 두 가지의 구동법에 의한 발광 형태와 플라즈마의 특성을 조사한다. 램프 양단에 고전압을 인가하는 구동 방식에서, 빛은 고전압이 인가된 램프 양 끝에서 중앙으로 빛의 방출이 전파되며, 램프 길이 전체에 대하여 휘도가 균일하다. 램프 한쪽에 고전압을 인가하고 다른 한쪽은 접지한 구동에서, 빛의 방출은 고전압이 인가된 전극에서 접지된 전극 방향으로 전파되며, 고전압 쪽의 휘도가 높고 접지 쪽의 휘도가 낮아 램프 길이 방향으로 휘도가 불균일하다. 이러한 발광 전파 신호로부터 전자의 표류 속도를 계산하여, 전자의 온도와 밀도를 얻는다. 외부전극 형광램프의 사용 휘도의 영역인 $10,000{\sim}15,000cd/m^2$에 대하여, 전자 온도 $(kT_e)$는 $1.3{\sim}2.7eV$, 플라즈마의 밀도 $(n_e)$는 $(1.6{\sim}3.6){\times}10^{16}m^{-3}$를 얻었다.

• 한국재료학회지
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• 제28권1호
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• pp.38-42
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• 2018

Continuous efforts are being made to improve the efficiency of Si solar cells, which is the prevailing technology at this time. As opposed to the standard front-lit solar cell design, the back-lit design suffers no shading loss because all the metal electrodes are placed on one side close to the pn junction, which is referred to as the front side, and the incoming light enters the denuded back side. In this study, a systematic comparison between the two designs was conducted by means of computer simulation. Medici, a two-dimensional semiconductor device simulation tool, was utilized for this purpose. The $0.6{\mu}m$ wavelength, the peak value for the AM-1.5 illumination, was chosen for the incident photons, and the minority-carrier recombination lifetime (${\tau}$), a key indicator of the Si substrate quality, was the main variable in the simulation on a p-type $150{\mu}m$ thick Si substrate. Qualitatively, minority-carrier recombination affected the short circuit current (Isc) but not the opencircuit voltage (Voc). The latter was most affected by series resistance associated with the electrode locations. Quantitatively, when ${\tau}{\leq}500{\mu}s$, the simulation yielded the solar cell power outputs of $20.7mW{\cdot}cm^{-2}$ and $18.6mW{\cdot}cm^{-2}$, respectively, for the front-lit and back-lit cells, a reasonable 10 % difference. However, when ${\tau}$ < $500{\mu}s$, the difference was 20 % or more, making the back-lit design less than competitive. We concluded that the back-lit design, despite its inherent benefits, is not suitable for a broad range of Si solar cells but may only be applicable in the high-end cells where float-zone (FZ) or magnetic Czochralski (MCZ) Si crystals of the highest quality are used as the substrate.

• 전기학회논문지
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• 제60권2호
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• pp.344-348
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• 2011

A layer of $TiO_2$ thin film less than ~200nm in thickness, as a blocking layer, was deposited by 13.56 MHz radio frequency magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells (DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte ($I^-/{I_3}^-$). The presented DSCs were fabricated with working electrode of F:$SnO_2$(FTO) glass coated with blocking $TiO_2$ layer, dye-attached nanoporous $TiO_2$ layer, gel electrolyte and counter electrode of Pt-deposited FTO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells. The, electrochemical impedances of DSCs using this electrode were $R_1$: 13.9, $R_2$: 15.0, $R_3$: 10.9 and $R_h$: $82{\Omega}$. The $R_2$ impedance related by electron movement from nanoporous $TiO_2$ to TCO showed lower than that of normal DSCs. The photo-conversion efficiency of prepared DSCs was 5.97% ($V_{oc}$: 0.75V, $J_{sc}$: 10.5 mA/$cm^2$, ff: 0.75) and approximately 1% higher than general DSCs sample.

• 한국융합학회논문지
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• 제11권11호
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• pp.183-187
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• 2020

LCD BLU의 CCFL 전극에 사용되는 몰리브덴 전극의 주요소재인 몰리브덴 컵과 몰리브덴 핀은 국내 가공기술이 개발되지 못하여 전량 일본에서 수입하여 사용되고 있어 CCFL 제조업체들의 납기 및 경쟁력에 부담을 주고 있다. 본 연구에서는 LCD BLU의 CCFL 전극에 사용되는 몰리브덴 핀의 제조 기술을 개발하는 연구로 직선처리 기술개발, 몰리브덴 와이어 표면처리 기술개발, 와이어 절단기술 개발, 몰리브덴 핀의 제작, 검사용 JIG와 Fixture 설계 및 제작, 몰리브덴 핀 시제작 및 해석, 몰리브덴 핀 전수검사 기술개발에 관한 연구를 수행하였으며 본 논문에서는 몰리브덴 핀 제작에 있어 전수검사기 융합설계에 대한 연구를 다루고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.74-76
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• 2006

An external electrode fluorescent lamp (EEFL) has an advantage of a long lifetime in the ear1y stages of the study on plasma discharge, interest in the lamp continues. Researches on the operation of external electrode fluorescent lamps have focused mainly on its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, EEFL presented the possibility of using it as a light source for back-lights. However, because EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significant1y affected by frequency. Thus, this study verified the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examined the relationship between the change in the EEFL frequency and brightness by measuring the optical characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.

• Transactions on Electrical and Electronic Materials
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• 제8권6호
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• pp.268-273
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• 2007

In this study, It was studied about the luminance characteristics of 17 inch direct-type back light using EEFL(external electrode fluorescent lamp) and CCFL(cold cathode fluorescent lamp). The EEFL has a long life time because the electrode is installed outside of lamp. And it is produced in lower price than conventional CCFL. Moreover, it does not need process of installing internal electrode. However, the EEFL technology has several problems such as difficulty of designing driving inverter and preventing this phenomenon along the skin of lamps. We suggested two types of backlight unit for LCD TV application using the EEFL and the CCFL. We found optimized optical design parameters. We set the optical variation parameters such as lamp height, lamp distance, total thickness, and angles of inner walls. We achieved 7580 nits of center luminance, 82% of luminance uniformity by using 20 lamps of the EEFL and 7297 nits of center luminance, 78% of luminance uniformity by using 16 lamps of the CCFL.

• 한국조명전기설비학회지:조명전기설비
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• 제8권3호
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• pp.54-63
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• 1994

본 연구에서는 판상스페이서 위에 침전극을 고정하고 gap간격 40[mm]에 평판전극을 설치한 gap 간에 10[mm]간격으로 나누어 각 구간내에 스페이서와 같은 재질의 Barrier를 설치하고 파티클을 두었을 때 AC 및 정극성 DC 전압에서의 방전로와 FOV에 대해 연구한 결과 다음과 같은 결론을 얻엇다. 1) Barrier가 고전위측에 위치한 경우와 파티클이 Barrier뒤에 은폐된 경우가 FOV가 높다. 2) 침전극 선단에 파티클 위치할 때 심한 FOV의 감소가 있다. 3) 파티클이 전극간에 게재되면 방전로는 파티클을 경유하므로 FOV는 감소한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.428-428
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• 2007

In this study, It was studied about the luminance characteristics of 17inch direct-type back light using EEFL(External Electrode Fluorescent Lamp). EEFI has a long life time because the electrode is installed outside of lamp. And it is produced low price than conventional CCFL. It does not need process of installing internal electrode. But EEFL technology has several problems such as difficulty of design driving inverter, and prevents leckage current along the skin of lamps. Therefore, by the optimizing of inverter properties, 7525 nit center luminance was acquired in almost same power consumption condition. It was almost same luminance in CCFL backlight unit. And it was operated stably in low operating temperature such as the value of $40^{\circ}C$, so that it was adopted in conventional LCD-TV application.