• 반도체디스플레이기술학회지
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• 제13권2호
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• pp.1-5
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• 2014

Transparent and conducting aluminum-doped ZnO electrodes were fabricated by atomic layer deposition methods. The electrode showed the lowest resistivity of $5.73{\times}10^{-4}{\Omega}cm$ at a 2.5% cyclic layer deposition ratio of Trimethyl-aluminum and Diethyl-zinc chemicals. The electrodes showed minimum resistivity when deposited at a temperature of $225^{\circ}C$. The electrode also showed optical transmittance of about 92% at 300 nm. An organic solar cell made with a 300-nm-thick aluminum-doped ZnO electrode exhibited 2.0% power conversion efficiency.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.209-209
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• 2012

High-efficient transparent conductive oxide (TCO) film-embedding Si heterojunction solar cells were fabricated. An additional doping was not applied for heterojunction solar cells due to the spontaneous junction formation between TCO films and an n-type Si substrate. Three different TCO coatings were formed by sputtering method for an Al-doped ZnO (AZO) film, an indium-tin-oxide (ITO) film and double stacks of ITO/AZO films. An improved crystalline ITO film was grown on an AZO template upon hetero-epitaxial growth. This double TCO films-embedding Si heterojunction solar cell provided significantly enhanced efficiency of 9.23% as compared to the single TCO/Si devices. The effective arrangement of TCO films (ITO/AZO) provides benefits of a lower front contact resistance and a smaller band offset to Si leading enhanced photovoltaic performances. This demonstrates a potential scheme of the effective TCO film-embedding heterojunction Si solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.39.1-39.1
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• 2010

이종접합태양전지는 단결정 실리콘 기판 표면에 고품질 비정질 실리콘층을 적층함으로써 전기의 근원인 전하의 재결합 손실을 줄여 높은 개방전압을 얻을 수 있다는 특징이 있다. 초박형 태양전지는 기존 태양전지보다 뛰어난 광전변환 특성(Photovoltaic characteristic)을 가지고 두께가 얇아 제품 형상 시 자유도가 높아진다. 본 논문에서는 n-type Bare wafer($160{\sim}180{\mu}m$)를 이용하여 $50{\mu}m$의 웨이퍼를 제작하였다. a-Si:H(p)_a-Si:H(i)_c-Si(n)의 광흡수층 구조를 성막하여 cell을 제작하였다. 그 결과 Voc(Open Circuit Voltage)가 0.666, Jsc(Short-Circuit Current)가 34.77, FF(Fill Factor) 69.413, Efficency 16.07%를 달성했다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.189-189
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• 2012

Lead sulfide (PbS) nanocrystal quantum dots (NQDs) are promising materials for various optoelectronic devices, especially solar cells, because of their tunability of the optical band-gap controlled by adjusting the diameter of NQDs. PbS is a IV-VI semiconductor enabling infrared-absorption and it can be synthesized using solution process methods. A wide choice of the diameter of PbS NQDs is also a benefit to achieve the quantum confinement regime due to its large Bohr exciton radius (20 nm). To exploit these desirable properties, many research groups have intensively studied to apply for the photovoltaic devices. There are several essential requirements to fabricate the efficient NQDs-based solar cell. First of all, highly confined PbS QDs should be synthesized resulting in a narrow peak with a small full width-half maximum value at the first exciton transition observed in UV-Vis absorbance and photoluminescence spectra. In other words, the size-uniformity of NQDs ought to secure under 5%. Second, PbS NQDs should be assembled carefully in order to enhance the electronic coupling between adjacent NQDs by controlling the inter-QDs distance. Finally, appropriate structure for the photovoltaic device is the key issue to extract the photo-generated carriers from light-absorbing layer in solar cell. In this step, workfunction and Fermi energy difference could be precisely considered for Schottky and hetero junction device, respectively. In this presentation, we introduce the strategy to obtain high performance solar cell fabricated using PbS NQDs below the size of the Bohr radius. The PbS NQDs with various diameters were synthesized using methods established by Hines with a few modifications. PbS NQDs solids were assembled using layer-by-layer spin-coating method. Subsequent ligand-exchange was carried out using 1,2-ethanedithiol (EDT) to reduce inter-NQDs distance. Finally, Schottky junction solar cells were fabricated on ITO-coated glass and 150 nm-thick Al was deposited on the top of PbS NQDs solids as a top electrode using thermal evaporation technique. To evaluate the solar cell performance, current-voltage (I-V) measurement were performed under AM 1.5G solar spectrum at 1 sun intensity. As a result, we could achieve the power conversion efficiency of 3.33% at Schottky junction solar cell. This result indicates that high performance solar cell is successfully fabricated by optimizing the all steps as mentioned above in this work.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.60-63
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• 1993

We have prepared n-CdS/p-InP hetero- junction solar cells by thermal evaporation. The efficiency under the optium conditions without the grid line contact was 7.3%, and the solar cell having glid line contact with SiO AR coating was the open circuit voltage of 0.71V, the short circuit voltage current density of 15mA/cm$^2$, the fill factor of 0.73, and the efficiency of 11.5%. As result of photoresponse in 400-1000nm wavelength the cutoff of n-CdS/p-InP solar at 500nm results from absorption by the CdS \"window\" and the cutoff at 930 nm result from absorption by the InP.

• Transactions on Electrical and Electronic Materials
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• 제6권3호
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• pp.124-127
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• 2005

It has been a long time since organic solar cells were expected as a low-cost energy-conversion device. Although practical use of them has not been achieved, technological progress continues. Morphology of the materials, organic/inorganic interface, metal cathodes, molecular packing and structural properties of the donor and acceptor layers are essential for photovoltaic response. We have fabricated solar cell devices based on zinc-phthalocyanine(ZnPc) as donor(D) and fullerene$(C_60)$ as electron acceptor(A) with doped charge transport layers, and BCP and $Alq_3$ as an exciton blocking layer(EBL). We have measured the photovoltaic characteristics of the solar cell devices using the Xe lamp as a light source. We were use of $Alq_3$ layer leads to external power conversion efficiency was $2.65\%$ at illumination intensity $100\;mW/cm^2$. Also we confirmed the optimum thickness ratio of the DA hetero-junction is about 1:2.

• 한국방사선학회논문지
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• 제3권1호
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• pp.11-15
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• 2009

본 연구에서는 헤테로 접합을 이용하여 누설전류를 저감 시키는 기술을 적용하여 Particle-In -Binder을 이용한 방사선 영상 센서의 변환 물질을 개발하였다. 이는 디지털 방사선 영상 검출기의 두 가지 방식 중 하나인 직접방식에 사용되는 핵심 소자로 기존의 비정질 셀레늄(Amorphous Selenium)을 대체하여 더욱 효율이 높은 후보 물질들이 연구되어지는 가운데 태양전지와 반도체 분야에서 이미 많이 사용되어온 이종접합(Hetero junction)을 이용해 누설 전류를 저감 시키는데 그 목적이 있다. 본 연구에서 사용되는 Particle-In -Binder 제작 방법은 검출 물질 제작이 용이하고 높은 수율과 대면적의 검출기 제작에 적합하나 높은 누설 전류가 의료 영상 시스템에 있어서 문제가 되어 오고 있다. 이러한 단점을 보완하기 위해 다층 구조를 이용하여 누설 전류를 저감시킨다면 Particle-In -Binder을 이용하여 간편하게 향상된 효율의 디지털 방사선 검출기를 제작 할 수 있다고 사료 되어 진다. 본 연구에서는 누설전류 및 민감도, 그리고 선형성에 대한 전기적 신호를 측정하여 제작된 다층 구조의 방사선 검출 물질의 특성 평가가 이루어 졌다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.481.2-481.2
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• 2014

Bulk hetero junction (BHJ) polymer solar cell (PSCs) is one of the most promising fields as alternative energy source. Especially, the development of new p-type conjugated polymer is one of the main issues to get core technology. In this study, we investigated the chemical doping effects of incorporating 3,6-carbazole units into conjugated polymers based on 2,7-carbazole. We assessed the structural effects of this chemical doping by measuring the photovoltaic device performance of the copolymers with and without annealing. Note that the use of nanostructures in the bulk heterojunction layer could be a major obstacle to commercialization because nano-morphologies are frequently unstable at high temperatures. Therefore, the development of thermally stable polymer:fullerene blends with optimized PCEs is an important goal in this area of research. We studied the morphologies of the copolymers incorporating 3,6-carbazole units resulting from thermal annealing to investigate the effects of the difference between the T g values of the 2,7-carbazole unit and the 3,6-carbazole unit.

• 마이크로전자및패키징학회지
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• 제17권2호
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• pp.63-67
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• 2010

본 연구에서는 P3HT와 PCBM 물질을 전자도너와 억셉터 광활성층 물질로 사용하여 벌크이종접합 구조를 갖는 Glass/ITO/PEDOT:PSS/P3HT-PCBM/Al 구조의 유기박막태양전지를 제작하였다. P3HT와 PCBM은 각각 0.5 wt%의 농도로 톨루엔 용액에 용해하였다. 광활성층 농도를 최적화하기 위하여 P3HT:PCBM= 3:4, 4:4, 4:3 wt%의 농도비로 소자를 제작하고, 농도비에 따른 전기적 특성을 조사하였다. 또한 활성층의 후속열처리 온도가 소자의 전기적 특성에 미치는 영향을 조사하였다. P3HT와 PCBM의 농도비가 4:4 wt%의 비율에서 가장 우수한 전기적 특성을 나타내었으며, 이때 단락전류밀도 ($J_{SC}$), 개방전압 ($V_{OC}$), 및 충실인자 (FF)는 4.7 $mA/cm^2$, 0.48 V 및 43.1%를 각각 나타내었다. 또한 전력변환효율(PCE)은 0.97%의 값을 얻었다. 최적화된 농도비를 갖는 태양전지 소자에 대해 $150^{\circ}C$에서 5분, 10분, 15분, 20분간 후속 열처리를 실시한 결과 P3HT 전자도너의 흡광계수가 증가하는 경향을 보였다. 후속 열처리 조건이 $150^{\circ}C$에서 15분인 경우 전기적 특성이 열처리 하지 않은 소자에 비해 특성이 개선되었다. 즉, 이때의 전기적 특성은 $J_{SC},\;V_{OC}$, FF, PCE의 값이 각각 7.8 $mA/cm^2$, 0.55 V, 47%, 2.0%를 나타내었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.61.1-61.1
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• 2010

$CuIn_{1-x}-GaxSe_2$ based materials with direct bandgap and high absorption coefficient are promising materials for high efficiency hetero-junction solar cells. CIGS champion cell efficiency(19.9%, AM1.5G) is very close to polycrystalline silicon(20.3%, AM1.5G). A reduction in the price of CIGS module is required for competing with well matured silicon technology. Price reduction can be achieved by decreasing the manufacturing cost and by increasing module efficiency. Manufacturing cost is mostly dominated by capital cost. Device properties of CIGS are strongly dependent on doping, defect chemistry and structure which in turn are dependent on growth conditions. The complex chemistry of CIGS is not fully understood to optimize and scale processes. Control of the absorber grain size, structural quality, texture, composition profile in the growth direction is important to achieving reliable device performance. In the present work, CIS nanoparticles were prepared by a simple wet chemical synthesis method and their structural and optical properties were investigated. XRD patterns of as-grown nanopowders indicate CIS(Cubic), $CuSe_2$(orthorhombic) and excess selenium. Further, as-grown and annealed nanopowders were characterized by HRTEM and ICP-OES. Grain growth of the nanopowders was followed as a function of temperature using HT-XRD with overpressure of selenium. It was found that significant grain growth occurred between $300-400^{\circ}C$ accompanied by formation of ${\beta}-Cu_{2-x}Se$ at high temperature($500^{\circ}C$) consistent with Cu-Se phase diagram. The result suggests that grain growth follows VLS mechanism which would be very useful for low temperature, high quality and economic processing of CIGS based solar cells.