• 한국재료학회지
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• 제9권12호
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• pp.1155-1159
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• 1999

플라즈마 화학증착 (PECVD) 장비를 이용하여 $SnO_2$ 투명전도막이 피막된 유리기판 위에 p-SiC/i-Si/n-Si 이종접합 태양전지를 제작하였다. p-SiC 층의 증착중에 기체조성 x=$CH_4/\;(SiH_4+CH_4)$의 변화에 대한 태양전지의 광기전 특성을 관찰하였다. 기체조성(x)이 0~0.4의 범위에서 p-SiC 창층의 광학적 밴드갭의 증가로 인하여 태양전지의 효율은 증가하였으나, 그 이상의 기체조성에서는 p-SiC/i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 I-Si 층 사이에 I-SiC 완충층을 삽입함으로써 크게 감소하였다. 그 결과 유효면적이 $1cm^2$인 glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag 구조의 박막 태양전지는 100mW/$cm^2$ 조도 하에서 8.6%의 효율을 나타내었다. ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615)

• 한국전기전자재료학회논문지
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• 제34권4호
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• pp.251-255
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• 2021

a-Si is commonly considered as a primary candidate for the formation of passivation layer in heterojunction (HIT) solar cells. However, there are some problems when using this material such as significant losses due to recombination and parasitic absorption. To reduce these problems, a wide bandgap material is needed. A wide bandgap has a positive influence on effective transmittance, reduction of the parasitic absorption, and prevention of unnecessary epitaxial growth. In this paper, the adoption of a-SiO_x:H as the intrinsic layer was discussed. To increase lifetime and conductivity, oxygen concentration control is crucial because it is correlated with the thickness, bonding defect, interface density (D_it), and band offset. A thick oxygen-rich layer causes the lifetime and the implied open-circuit voltage to drop. Furthermore the thicker the layer gets, the more free hydrogen atoms are etched in thin films, which worsens the passivation quality and the efficiency of solar cells. Previous studies revealed that the lifetime and the implied voltage decreased when the a-SiOx thickness went beyond around 9 nm. In addition to this, oxygen acted as a defect in the intrinsic layer. The D_it increased up to an oxygen rate on the order of 8%. Beyond 8%, the D_it was constant. By controlling the oxygen concentration properly and achieving a thin layer, high-efficiency HIT solar cells can be fabricated.

• 공업화학
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• 제22권1호
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• pp.15-20
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• 2011

2,3-Dimethyl-5,8-dithiophen-2-yl-quinoxaline을 기본 골격으로 한 poly[2,3-dimethyl-5,8-dithiophene-2-yl-quinoxaline-alt-9,9-dihexyl-9H-fluorene] (PFTQT)과 poly[2,3-dimethyl-5,8-dithiophene-2-yl-quinoxaline-alt-10-hexyl-10H-phenothiazine] (PPTTQT)을 Suzuki coupling법을 이용하여 중합 하였다. 합성된 고분자들은 chloroform, chlorobenzene, o-dichlorobenzene, tetrahydrofuran (THF), toluene과 같은 유기용매에 대한 용해도가 우수하였고, PFTQT의 최대흡수파장과 밴드 갭은 각각 440 nm와 2.30 eV이고, PPTTQT의 경우는 각각 445 nm와 2.23 eV이었다. PFTQT의 HOMO 및 LUMO 에너지준위는 -6.05와 -3.75 eV이고, PPTTQT의 경우는 각각 -5.89와 -3.66 eV이었다. 합성된 고분자들과 전자 받개 물질인 (6)-1-(3-(methoxycarbonyl)-{5}-1-phenyl[5,6]-fullerene (PCBM)을 1 : 2의 중량비로 블렌딩하여 제작한 태양전지의 효율은 AM (air mass) 1.5 G, 1 sun 조건($100mA/cm^2$)에서 PFTQT는 0.24%, PPTTQT의 경우는 0.16%로 측정되었다. 그리고 소자의 단락전류 밀도($J_{sc}$), FF (fill factor)와 개방전압($V_{oc}$)은 PFTQT의 경우 각각 $0.97mA/cm^2$, 29%, 0.86 V이며, PPTTQT의 경우 각각 $0.80mA/cm^2$, 28%, 0.71 V이었다.

• 한국항해항만학회지
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• 제31권3호
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• pp.229-233
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• 2007

본 논문은 브이용 PV 시스템 성능과 최대전력점추적기의 알고리즘에 대하여 기술하고자 한다 현재 운영되고 있는 브이는 대부분 태양광을 활용한 독립형 전력 시스템을 이용하고 있다. 이러한 태양광 전력 시스템은 직류 출력 특성을 가지고 있으며 직류 버스와 연결된다. 태양광 전지판의 I-V 출력 특성은 일사량, 전지판의 온도에 따라 변화하며 태양광 전지 마다 그 특성이 각기 다르게 나타나기 때문에 태양광 전지는 최대전력추적방식의 알고리즘에 의해 운영되어야 한다. 이에 본 논문은 태양광 전지의 특성, 최대전력추적방식, 태양광 전지판의 최적경사각을 논의하고자 한다.

• 한국태양에너지학회 논문집
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• 제32권spc3호
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• pp.194-198
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• 2012

Crystalline silicon solar cell remains the major player in the photovoltaic marketplace with 80% of the market, despite the development of various thin film technologies. Silicon's excellent efficiency, stability, material abundance and low toxicity have helped to maintain its position of dominance. However, the cost of silicon materials remains a major barrier to reducing the cost of silicon photovoltaics. Using the crystalline silicon wafer with thinner thickness is the promising way for cost and material reduction in the solar cell production. However, the thinner the silicon wafer is, the worse bow phenomenon is induced. The bow phenomenon is observed when two or more layers of materials with different temperature expansion coefficiencies are in contact, in this case silicon and aluminum. In this paper, the solar cells were fabricated with different thicknesses of Al layer in order to reduce the bow phenomenon. With less amount of paste applications, we observed that the bow could be reduced by up to 40% of the largest value with 120 micron thickness of the wafer even though the conversion efficiency decrease by 0.5% occurred. Since the bowed wafers lead to unacceptable yield losses during the module construction, the reduction of bow is indispensable on thin crystalline silicon solar cell. In this work, we have studied on the counterbalance between the bow and conversion efficiency and also suggest the formation of enough back surface field (BSF) with thinner Al layer application.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.88.1-88.1
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• 2010

Organic dyes, because of their many advantages, such as high molar extinction coefficients, convenience of customized molecular design for desired photophysical and photochemical properties, inexpensiveness with no transition metals contained, and environment-friendliness, are suitable as photosensitizers for the Dye-sensitized Solar Cell (DSSC). The efficiency of DSSC based on metal-free organic dyes is known to be much lower than that of Ru dyes generally, but a high solar energy-to-electricity conversion efficiency of up to 8% in full sunlight has been achieved by Ito et al. using an indoline dye. This result suggests that smartly designed and synthesized metal-free organic dyes are also highly competitive candidates for photosensitizers of DSSCs with their advantages mentioned above. Recently, the performance of DSSC based on metal-free organic dyes has been remarkably improved by several groups. We had reported the novel organic dye with double electron acceptor chromophore, which was a new strategy to design an efficient photosensitizer for DSSC. To verify the strategy, we synthesized organic dyes whose geometries, electronic structures and optical properties were derived from preceding density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. In this paper, we successfully synthesized the chromophore containing multi-acceptor push-pull system from triphenylamine with thiophene moieties as a bridge unit. Organic dyes with a single electron acceptor and double acceptor system were also synthesized for comparison purposes. The photovoltaic performances of these dyes were compared, and the recombination dark current curves and the incident photon-to-current (IPCE) efficiencies were also measured in order to characterize the effects of the multi-anchoring groups on the open-circuit voltage and the short-circuit current. In order to match specifications required for practical applications to be implemented outdoors, light soaking and thermal stability tests of these DSSCs, performed under $100mWcm^{-2}$ and $60^{\circ}C$ for 1000h.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.75.1-75.1
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• 2010

Dye sensitized solar cells(DSSCs) have been extensively studied due to their various advantages such as low production cost, colorful design, and eco-friendly process. Long optical path length is one of the most effective method to improve light harvest efficiency for DSSCs. Multi-layered $TiO_2$ nano-structured film with scattering layer has been studied to generate scattering effect by many researchers. It was expected that the difference of refractive index between $TiO_2$ particles and glass frit would generate the light scattering effect and provide the long optical path length. Therefore, to enhance the scattering effect, the frits of $Bi_2O_3-B_2O_3$-ZnO glass system that has the different refractive index were added to $TiO_2$ pastes in this study. First of all, the absorbance and haze factor of $TiO_2$ electrode with dyes and the refractive index of glass frit and $TiO_2$ were measured, respectively. To study the effect of frits, the efficiencies of DSSCs added glass frit and without glass frit were compared. Our results showed slightly higher efficiency with the different absorbance and haze factor of $TiO_2$ and glass frit. It was considered that the light scattering effect would be improved with adding frits to $TiO_2$ paste. Our preliminary studies will be useful for increasing efficiency of DSSCs.

• 신재생에너지
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• 제16권3호
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• pp.1-12
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• 2020

Shingled technology is the latest cell interconnection technology developed in the photovoltaic (PV) industry due to its reduced resistance loss, low-cost, and innovative electrically conductive adhesive (ECA). There are several advantages associated with shingled technology to develop cell to module (CTM) such as the module area enlargement, low processing temperature, and interconnection; these advantages further improves the energy yield capacity. This review paper provides valuable insight into CTM loss when cells are interconnected by shingled technology to form modules. The fill factor (FF) had improved, further reducing electrical power loss compared to the conventional module interconnection technology. The commercial PV module technology was mainly focused on different performance parameters; the module maximum power point (Pmpp), and module efficiency. The module was then subjected to anti-reflection (AR) coating and encapsulant material to absorb infrared (IR) and ultraviolet (UV) light, which can increase the overall efficiency of the shingled module by up to 24.4%. Module fabrication by shingled interconnection technology uses EGaIn paste; this enables further increases in output power under standard test conditions. Previous research has demonstrated that a total module output power of approximately 400 Wp may be achieved using shingled technology and CTM loss may be reduced to 0.03%, alongside the low cost of fabrication.

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

• 한국재료학회지
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• 제7권10호
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• pp.856-862
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• 1997

박막형 CdTe/CdS 태양전지의 배면전극(back contacts)물질로서 Cu도핑된 ZnTe 박막(ZnTe:Cu)을 전착법(electroplating)으로 제조하는 연구를 수행하였다. Sulfate계의 전해질 수용액에서 CdTe 기판과 투명전극으로 코팅된 유리(In$_{2}$O$_{3}$: Sn, ITO)기판 위에 ZnTe 박막을 코팅하는 방법으로써 potentiostat와 기판(cathode), Pt counter electrode, Ag/AgCI 표준전극으로 구성된 장치를 사용하여 pH=2.5-4, T=70-8$0^{\circ}C$, 0.02M $Zn^{2+}$ 1x$10^{-4}$M TeO$_{2}$, 0.2M $K_{2}$SO$_{4}$조건에서 -0.800 Vs~-0.975 V 범위의 전압(V$_{a}$ )에 걸쳐 실험하였다. ITO박막을 기판으로 사용하여 cyclic voltammogram을 작성한 결과 약 -0.50 V 에서 Te환원 peak이 나타났다. Auger electron spectroscopy (AES)로 조성분석한 결과 표면에서 Zn signal이 강하게 나왔고 시편의 두께에 따라 Zn의 signal감소하는 반면 Cd signal은 증가하는 것이 확인되었다. SEM 사진으로부터 ZnTe의 표면이 작은 입자 (0.2$\mu\textrm{m}$ 이하)로 구성되어 있으며 낮은 V$_{a}$ 에서는 입자가 작아지면서 조직이 치밀해짐이 관찰되었다. Optical transmission방법에 의하여 ITO기판위에 입혀진 박막의 밴드갭은 2.5 eV으로 측정되었다. 수용액중의 Cu$_{2+}$와 triethanolamine(TEA)은 산성용액에서 착물형성이 이루어지지 않았으며 1,10-phenanthroline과는 pH=2에서도 착물이 형성되었다.