• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.44.2-44.2
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• 2010

차세대 태양전지로써 플렉서블 태양전지에 대한 연구가 활발하다. CIS 박막태양전지의 경우도 Glass base 태양전지 시스템 연구와 더불어 금속과 플라스틱 등 연성 기판재를 이용한 전지 시스템에 관한 연구가 진행 되고 있다. 그러나 태양전지의 핵심 부자재라고 할 수 있는 기판재에 대한 체계적인 연구는 미흡한 실정이다. 특히 플렉서블 박막태양전지용 기판재와 그 위에 적층되어 태양전지를 구성하는 박막 소재의 열팽창 거동들 사이에 차이가 있어 태양전지 시스템에 결함을 야기할 수 있다. 본 연구에서는 플렉서블 태양전지용으로 적용되거나 연구되고 있는 SUS 300 계열과 SUS 400번 계열을 중심으로 철계 연성 기판재의 열팽창 거동을 비교 분석하였다. 그리고 CIS 박막태양전지 제조 공정인 고온 박막 생성 공정의 열분석을 통해 기판재의 성능을 평가 하였다.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.103-109
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• 2014

Highly efficient hydrogenated nanocrystalline silicon (nc-Si:H) thin-film solar cells were prepared on flexible stainless steel substrates using plasma-enhanced chemical vapor deposition. To enhance the performance of solar cells, material properties of back reflectors, n-doped seed layers and wide bandgap nc-SiC:H window layers were optimized. The light scattering efficiency of Ag back reflectors was improved by increasing the surface roughness of the films deposited at elevated substrate temperatures. Using the n-doped seed layers with high crystallinity, the initial crystal growth of intrinsic nc-Si:H absorber layers was improved, resulting in the elimination of the defect-dense amorphous regions at the n/i interfaces. The nc-SiC:H window layers with high bandgap over 2.2 eV were deposited under high hydrogen dilution conditions. The vertical current flow of the films was enhanced by the formation of Si nanocrystallites in the amorphous SiC:H matrix. Under optimized conditions, a high conversion efficiency of 9.13% ($V_{oc}=0.52$, $J_{sc}=25.45mA/cm^2$, FF = 0.69) was achieved for the flexible nc-Si:H thin-film solar cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.52-52
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• 2011

A novel deposition process for n-type nanocrystalline silicon (n-type nc-Si) thin films at room temperature has been developed by adopting the neutral beam assisted chemical vapor deposition (NBa-CVD). During formation of n-type nc-Si thin film by the NBa-CVD process with silicon reflector electrode at room temperature, the energetic particles could induce enhance doping efficiency and crystalline phase in polymorphous-Si thin films without additional heating on substrate; The dark conductivity and substrate temperature of P-doped polymorphous~nano crystalline silicon thin films increased with increasing the reflector bias. The NB energy heating substrate(but lower than $80^{\circ}C$ and increase doping efficiency. This low temperature processed doped nano-crystalline can address key problem in applications from flexible display backplane thin film transistor to flexible solar cell.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.128.2-128.2
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• 2011

스테인레스 스틸 유연기판 위에 플라즈마 화학기상 증착법 (plasma enhanced chemical vapor deposition)을 이용하여 nip 구조의 미세결정질 실리콘 박막 태양전지 (microcrystalline silicon thin film solar cell)를 제조하고 i ${\mu}c$-Si:H광 흡수층과 p ${\mu}c$-Si:H 사이에 i a-Si:H 버퍼 층을 삽입하여 i/p 계면특성을 개선하고 이에 따른 태양전지 성능특성 변화를 조사하였다. ${\mu}c$-Si:H 박막으로 이루어진 i/p 계면에서의 구조적, 전기적 결함은 태양전지 내에서 생성된 캐리어의 재결합과 shunt resistance 감소를 초래하여 개방전압 (open circuit voltage) 및 곡선 인자 (fill factor)를 감소시키는 것으로 알려졌다. 제조된 미세결정질 실리콘 박막 태양전지는 SUS/Ag/ZnO:Al/n ${\mu}c$-Si:H/i ${\mu}c$-Si:H/p ${\mu}c$-Si:H 구조로 제작되었으며 i/p 계면 사이의 i a-Si;H 버퍼층 두께를 변화시키고 이에 따른 태양전지의 특성을 조사하였다. 태양전지의 구조적, 전기적 특성 변화는 Scanning Electron Microscope (SEM), UV-visible-nIR spectrometry, Photo IV와 Dark IV를 통하여 조사하였다.

• Korean Journal of Materials Research
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• v.20 no.10
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• pp.501-507
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• 2010

Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from $25^{\circ}C$ to $500^{\circ}C$, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at $500^{\circ}C$, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the $J_{sc}$ values from 9.94 mA/$cm^2$ for the flat Ag back reflector at $25^{\circ}C$ to 13.36 mA/$cm^2$ for the rough one at $500^{\circ}C$. A conversion efficiency of 7.60% ($V_{oc}$ = 0.93, $J_{sc}$ = 13.36 mA/$cm^2$, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.

• Journal of the Korean institute of surface engineering
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• v.46 no.2
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• pp.61-67
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• 2013

Thin film solar cells have attracted much attention due to their high cell efficiency, comparatively low process cost, and applicability to flexible substrates. In particular, CIGS solar cells have been widely studied and produced because they demonstrated the highest cell efficiency. However, the deposition process of CIGS films generally includes the selenization process conducted at elevated temperature using toxic $H_2Se$ gas. To avoid this selenization process, CIGS thin films were, in this study, deposited by RF sputtering using single composite CIGS target. In addition, the effects of sputtering bias voltage and heat treatment on the microstructural and morphological changes in deposited CIGS films were investigated and discussed.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.197-202
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• 2022

The CZTS solar cell is a thin film solar cell using an absorption layer composed of Cu, Zn, Sn, Se, and S, and is cheaper than a CIGS solar cell using In and Ga and more eco-friendly than a perovskite and CdTe solar cell using Pb and Cd. In this study, we conducted a bending test for flexible CZTS solar cells. Experiments were conducted in the direction of inner benidng with compressive stress and outer bending with tensile stress, and during the number of bending 1,000 times with a radius of curvature of 50 mmR, the efficiency of the solar cell decreased by up to 12.7%, and the biggest cause of efficiency reduction in both directions was a large decrease in parallel resistance.

• Journal of the Korean institute of surface engineering
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• v.52 no.1
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• pp.6-15
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• 2019

Metal-halide perovskite (MHP) solar cell is a promising candidate for next-generation flexible devices and the BIPV (Building-integrated photovoltaics) because it can exhibit high power conversion efficiencies over 23%, good bendability and low processing cost. However, MHP solar cells are commonly fabricated by the spin coating that is not a reliable method to produce large-scale commercial solar cells. A shear coating can be one of the potential candidates for the large-scale deposition method of MHP films. In this work, the influences of the process parameters such as solvents of precursor solution, substrate temperature, concentrations of precursor solution, and annealing time on the thin film growth of MHP were investigated for the shear coating process. This study presents the possibility of the shear coating process for large-scaled perovskite film fabrication and reveals the role of process condition in the thin film growth of perovskites.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.367-369
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• 2009

플렉서블 태양전지용 연성기판재에는 플라스틱재와 금속재가 있다. 기존의 연성기판인 플라스틱의 경우 열과, 내구성, 화학약품에 약하다는 단점이 있으며, 금속기판은 높은 생산원가, 박판화의 어려움 등의 문제를 안고 있다. 일반적으로 기판재와 cell을 구성하는 반도체 층의 열팽창 거동 차이에 의한 열 변형이 태양전지의 공정안정성에 영향을 주는 것으로 알려져 있으며, cell을 구성하는 반도체 층과 열팽창 거동이 유사한 금속기판재의 적용이 필요하다. Si 박막 태양전지의 경우 Si 열팽창 거동과 비슷한 특성을 갖는 기판재의 개발이 필요하다. 전주법을 적용하여 조성이 다른 Ni계 합금의 열팽창 거동을 TMA 장비를 사용하여 측정하였다. 그리고 전산해석 Tool을 활용하여 가상의 Si 박막 태양전지 제조공정을 설정하고 고온 공정온도에서 상온으로 냉각시 발생되는 층간 열변형 연구를 수행하였고 열팽창 거동이 다른 합금 상에 Si층을 증착하여 열 충격에 의한 결함 발생여부를 관찰하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.6
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• pp.577-582
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• 2013

AZO (aluminum-doped zinc oxide) is one of the best candidate materials to replace ITO (indium tin oxide) for TCOs (transparent conductive oxides) used in flat panel displays, organic light-emitting diodes (OLEDs), and organic solar cells (OSCs). In the present study, to apply an AZO thin film to the transparent electrode of an organic solar cell, a low-temperature selective atomic layer deposition (ALD) process was adopted to deposit an AZO thin film on a flexible poly-ethylene-naphthalate (PEN) substrate. The reactive gases for the ALD process were di-ethyl-zinc (DEZ) and tri-methyl-aluminum (TMA) as precursors and H2O as an oxidant. The structural, electrical, and optical characteristics of the AZO thin film were evaluated. From the measured results of the electrical and optical characteristics of the AZO thin films deposited on the PEN substrates by ALD, it was shown that the AZO thin film appeared to be comparable to a commercially used ITO thin film, which confirmed the feasibility of AZO as a TCO for flexible organic solar cells in the near future.