• 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.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.59.2-59.2
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• 2012

Polymer solar cells utilize bulk heterojunction (BHJ) type photo-active layer in which the electron donating polymer and electron accepting $C_{60}$ derivatives are blended. We found there is significant charge recombination at the interface between the BHJ active layer and electrode. The charge recombination at the interface was effectively reduced by inserting wide band gap inorganic interfacial layer, which resulted in efficiency and stability enhancement of BHJ polymer solar cell.

• 한국재료학회지
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• 제24권8호
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• pp.434-442
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• 2014

Serious environmental problems have been caused by the greenhouse effect due to carbon dioxide($CO_2$) or nitrogen oxides($NO_x$) generated by the use of fossil fuels, including oil and liquefied natural gas. Many countries, including our own, the United States, those of the European Union and other developed countries around the world; have shown growing interest in clean energy, and have been concentrating on the development of new energy-saving materials and devices. Typical non-fossil-fuel sources include solar cells, wind power, tidal power, nuclear power, and fuel cells. In particular, organic solar cells(OSCs) have relatively low power-conversion efficiency(PCE) in comparison with inorganic(silicon) based solar cells, compound semiconductor solar cells and the CIGS [$Cu(In_{1-x}Ga_x)Se_2$] thin film solar cells. Recently, organic cell efficiencies greater than 10 % have been obtained by means of the development of new organic semiconducting materials, which feature improvements in crystalline properties, as well as in the quantum-dot nano-structure of the active layers. In this paper, a brief overview of solar cells in general is presented. In particular, the current development status of the next-generation OSCs including their operation principle, device-manufacturing processes, and improvements in the PCE are described.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.154.2-154.2
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• 2016

In this work, we introduce a solution-processed CdS interlayer for use in inverted bulk heterojunction (BHJ) solar cells, and compare this material to a series of standard organic and inorganic cathode interlayers. Different combinations of solution-processed CdS, ZnO and conjugated polyelectrolyte (CPE) layers were compared as cathode interlayers on ITO substrates to construct inverted solar cells based on $PTB7:PC_{71}BM$ and a $P3HT:PC_{61}BM$ as photoactive layers. Introduction of a CdS interlayer significantly improved the power conversion efficiency (PCE) of inverted $PTB7:PC_{71}BM$ devices from 2.0% to 4.9%, however, this efficiency was still fairly low compared to benchmark ZnO or CPE interlayers due to a low open circuit voltage ($V_{OC}$), stemming from the deep conduction band energy of CdS. The $V_{OC}$ was greatly improved by introducing an interfacial dipole (CPE) layer on top of the CdS layer, yielding outstanding diode characteristics and a PCE of 6.8%. The best performing interlayer, however, was a single CPE layer alone, which yielded a $V_{OC}$ of 0.727 V, a FF of 63.2%, and a PCE of 7.89%. Using $P3HT:PC_{61}BM$ as an active layer, similar trends were observed. Solar cells without the cathode interlayer yielded a PCE of 0.46% with a poor $V_{OC}$ of 0.197 V and FF of 34.3%. In contrast, the use of hybrid ZnO/CPE layer as the cathode interlayer considerably improved the $V_{OC}$ of 0.599 V and FF of 53.3%, resulting the PCE of 2.99%. Our results indicate that the CdS layer yields excellent diode characteristics, however, performs slightly worse than benchmark ZnO and CPE layers in solar cell devices due to parasitic absorption below 550 nm. These results suggest that the hybrid inorganic/organic interlayer materials are promising candidates as cathode interlayers for high efficiency inverted solar cells through the modification of interface contacts.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.918-925
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• 2021

페로브스카이트 태양전지는 기존의 실리콘 태양전지를 대체하는 차세대 태양전지로서, 페로브스카이트 구조를 가진 유-무기 하이브리드 물질을 광 활성층으로 사용하는 태양전지 소자로 고효율, 저가의 용액 공정 및 저온 공정에 유리한 장점들을 가지고 있으며 지난 10년간 빠른 효율 향상을 보여주었다. 이러한 페로브스카이트 태양전지의 상용화 과정에서 대면적 코팅 방법에 대해서 연구개발이 진행되어야 한다. 대면적 페로브스카이트 태양전지 대면적 코팅 방법 중 하나로 슬롯-다이 코팅방법에 대해서 연구 진행하였다. 메니스커스를 이용하여 기판 위를 지나가며 용액을 코팅하는 방법으로 3D printer에 메니스커스를 장착하여 코팅을 할 수 있도록 하였다. 코팅 시 작용하는 변수로는 bed 온도, coating speed, N₂ blowing간격, N₂ blowing 높이, N₂ blowing세기등이 있으며 이를 조절하여 페로브스카이트 흡수층을 제작 진행하였으며, 대면적 소자 제작을 위한 코팅 조건을 최적화 하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.376-376
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• 2011

I-III-VI2 chalcopyrite compounds, particularly copper, indium, gallium selenide(Cu(InxGa1-x)Se2, CIGS), are effective light-absorbing materials in thin-film solar application. They are direct band-gap semiconductors with correspondingly high optical absorption coefficients. Also they are stable under long-term excitation. CIS (CIGS) solar cell reached conversion efficiencies as high as 19.5%. Several methods to prepare CIS (CIGS) absorber films have been reported, such as co-evaporation, sputtering, selenization, and electrodeposition. Until now, co-evaporation is the most successful technique for the preparation of CIS (CIGS) in terms of solar efficiency, but it seems difficult to scale up. CIS solar cells have been hindered by high costs associated with a fabrication process. Therefore, inorganic colloidal ink suitable for a scalable coating process could be a key step in the development of low-cost solar cells. Here, we will present the preparation of CIS photo absorption layer by a solution process using novel metal precursors. Chalcopyrite copper indium diselenide (CuInSe2) nanocrystals ranging from 5 to 20nm in diameter were synthesized by arrested precipitation in solution. For the fabrication of CIS photo absorption layer, the CuInSe2 colloidal ink was prepared by dispersing in organic solvent and used to drop-casting on molybdenum substrate. We have characterized the nanoparticless and CIS layer by XRD, SEM, TEM, and ICP.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.123.1-123.1
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• 2017

Hybrid solar cells have intensively studied in recent years due to their advantages such as cost effectiveness and possibility of applications in flexible and transparent devices. It is critical to fabricate individual layer composed of organic and inorganic materials in the hybrid solar cell at low cost. Therefore, it is required to manufacture cheaply and enhance the photon-to-electricity conversion efficiency of each layer in the flexible solar cell industry. In this research, we fabricated pure Cu metal mesh electrode prepared by using electroplating and/or electroless plating on the Ni mold which was manufacture through photolithography, electroforming, and polishing process. Copper mesh was formed on the surface of nickel metal working master when pulsed electrolytic copper deposition were performed at various plating parameters such as plating time, current density, and so on. After electrodeposition at 2ASD for 5~30seconds, the line/pitch/thickness of copper mesh sheet was $1.8{\sim}2.0/298/0.5{\mu}m$.

• Current Photovoltaic Research
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• 제4권2호
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• pp.68-79
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• 2016

The power conversion efficiency of perovskite solar cells has remarkably increased from 3.81% to 22.1% in the past 6 years. Perovskite solar cells, which are based on the perovskite crystal structure, are fabricated using organic-inorganic hybrid materials. The advantages of these solar cells are their low cost and simple fabrication procedure. Also, they have a band gap of about 1.6 eV and effectively absorb light in the visible region. For the commercialization of perovskite solar cells in the field of photovoltaics, the issue of their long term stability cannot be overlooked. Although the development of perovskite solar cells is unprecedented, their main drawback is the degradation of the perovskite structure by moisture. This degradation is accelerated by exposure to UV light, temperature, and external bias. This paper reviews the aforesaid reasons for perovskite solar cell degradation. We also discuss the research directions that can lead to the development of perovskite solar cells with high stability.

• 마이크로전자및패키징학회지
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• 제20권2호
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• pp.1-9
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• 2013

Recently flexible electronic devices have attracted a great deal of attention because of new application possibilities including flexible display, flexible memory, flexible solar cell and flexible sensor. In particular, development of flexible memory is essential to complete the flexible integrated systems such as flexible smart phone and wearable computer. Research of flexible memory has primarily focused on organic-based materials. However, organic flexible memory has still several disadvantages, including lower electrical performance and long-term reliability. Therefore, emerging research in flexible electronics seeks to develop flexible and stretchable technologies that offer the high performance of conventional wafer-based devices as well as superior flexibility. Development of flexible memory with inorganic silicon materials is based on the design principle that any material, in sufficiently thin form, is flexible and bendable since the bending strain is directly proportional to thickness. This article reviews progress in recent technologies for flexible memory and flexible electronics with inorganic silicon materials, including transfer printing technology, wavy or serpentine interconnection structure for reducing strain, and wafer thinning technology.

• 공업화학
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• 제25권5호
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• pp.447-454
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• 2014

유기태양전지는 제조비용이 저렴하고 플렉서블 전자소자에 적용이 가능하다는 장점들로 인해 최근 많은 연구가 진행되고 있다. 일반적인 정구조의 태양전지(conventional structured solar cell)의 경우 10%대의 향상된 발전 효율을 보이고 있으나, 여전히 기타 Si 및 CIGS 등과 같은 태양전지에 비해 낮은 효율과 짧은 수명은 상용화의 걸림돌로 작용하고 있다. 일반적으로 유기태양전지의 짧은 수명은 유기물의 광산화뿐만 아니라 수분 및 산소에 의한 음극, 양극 소재의 부식으로 인한 소재/소자 열화 문제로 설명되어지고 있다. 한편 이와 같은 문제점을 해결하기 위해 새로운 소자 구조(역구조 태양 전지; Inverted structured solar cell)가 제안되었으며 전자 수송층 및 기능성 계면 소재 연구를 통한 발전 효율 및 수명 향상에 관한 연구가 꾸준히 되고 있다. 그 결과 최근 2D/3D 산화 아연(ZnO) 소재를 역구조 태양전지의 전자 수송층으로 적용하고 건,습식 표면 후처리를 통해 약 9% 수준의 발전효율을 달성하였다. 본 총설에서는 ZnO를 기반으로 하는 전자 수송층 소재의 연구 동향 및 역구조 태양전지의 효율 향상 기술에 관한 최신 연구 동향을 소개하고자 한다.