• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.113.1-113.1
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• 2011

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active compo-nents in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT(Thin Film Transistor), which are printed withfunctional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manu-facturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and active layer which consist of the P3HT:PCBM. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

• Current Applied Physics
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• v.18 no.12
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• pp.1592-1599
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• 2018

The present study deals with the effect of dual cathode buffer layer (CBL) on the performance of bilayer of 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) and fullerene (C70)-based organic solar cell (OSC) with low donor concentration. OSC devices with CBLs have been fabricated using thermal vapor deposition technique. We report the use of lithium fluoride (LiF) and molybdenum trioxide ($MoO_3$) as CBLs. The insertion of LiF between C70 and aluminium (Al) electrode enhances the power conversion efficiency (PCE) of device from 1.89% to 2.47% but quenching of photogenerated excitons is observed at interface of C70 and LiF layers. Incorporation of $MoO_3$ between LiF and Al electrode further enhances PCE of device to 3.51%. This has also improved the material quality and device properties, by preventing the formation of gap states and diminishing exciton quenching.

• Current Photovoltaic Research
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• v.7 no.3
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• pp.55-60
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• 2019

Polymer:nonfullerene solar cells with an inverted-type device structure were fabricated by employing the bulk heterojunction (BHJ) active layers, which are composed of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) and 3,9-bis(6-methyl-2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-M). The BHJ layers were formed on a pre-patterned indium-tin oxide (ITO)-coated glass substrate by spin-coating using the blend solutions of PBDB-T and IT-M. The solar cell performances were investigated with respect to the cell position on the ITO-glass substrates. In addition, the short-term shelf lifetime of solar cells was tested by storing the PBDB-T:IT-M solar cells in a glovebox filled with inert gas. The results showed that the performance of solar cells was relatively higher for the cells close to the center of substrates, which was maintained even after storage for 24 h. In particular, the PCE of PBDB-T:IT-M solar cells was marginally decreased after storage for 24 h owing to the slightly reduced fill factor, even though the open circuit voltage was unchanged after 24 h.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.36-36
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• 2010

Currently, there are several newly developed energy resources for the future to replace petroleum resources such as hydrogen fuel cell, solar cell, wind power, and etc. Among them, solar cell has attracted a worldwide concern, because it has an enormous amount of resources. In general, a study of solar cells can be classified in to an area of bulk type and thin-film type. Inorganic solar cells based on silicon have been tremendously developed in technology and efficiency. However, since there are many lithographic steps, high processing temperature approximately $1000^{\circ}C$, and expensive raw materials, a manufacturing cost of device are nearly reaching a limit. Contrary to those disadvantages, organic solar cells can be manufactured at room temperature. Also, it has many advantages such as a low cost, easy fabrication of thin film, and possible manufacture to a large size. Because it can be made to be flexible, research and development on solar cells are actively in progress for the next generation. ever though an efficiency of the organic solar cell is low compared to that of inorganic one, a continuous study is needed. In this paper, we report optimal device structure obtained by a program simulation for design and development of highly efficient organic photovoltaic cells. we have also compared simulated results to experimental ones.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.71-75
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• 2022

Graphene oxide was stirred with a ZnCl₂:NaCl electrolyte and electrochemically coated by cyclic voltammetry to simplify the electron transpfer layer film forming process for organic solar cells and to fabricate an organic solar cell having it. The device structure is FTO/ZnO:graphene/P3HT:PCBM/PEDOT:PSS/Ag. Morphology and chemical properties of ETL were confirmed by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. As a result of XPS measurement, ZnO metal oxide and carbon bonding were simultaneously confirmed, and ZnO and graphene peaks were confirmed by Raman spectroscopy. The electrical characteristics of the manufactured solar cell were specified with a solar simulator, and the ETL device coated twice at a rate of 0.05 V/s showed the highest photoelectric conversion efficiency of 1.94%.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2269-2279
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• 2009

Six metal-free organic dyes having thiophene (1), benzene-thiophene (2), thiophene-benzene (3), thiophene-pyridine (4), thiophene-thiophene (5), and pyridine (6) linkers between 9,9-dimethylfluorenyl terminal group and $\alpha$-cyanoacrylic acid anchor were synthesized. Among them, organic dye 5 showed the longest ${\lambda}_{max}$ value (424 nm) in UV-Vis absorption spectrum, better incident monochromatic photon-to-current conversion efficiency (IPCE), highest short circuit photocurrent density ($J_{SC},\;9.33\;mA^2/cm^2$), and highest overall conversion efficiency ($\eta$, 3.91%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.11
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• pp.699-704
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• 2017

The amount of electric power for photovoltaic power generation depends on the location of the power plant and the direction of solar cell. The solar cell controls the generation of solar power plants. Therefore, the structure of solar cell, manufacturing method, and optic technology were factors contributing to increased solar cell efficiency; however, the technical limit has been reached. Herein, we propose a new method to increase the solar cell efficiency using a wavelength conversion technology that converts ultraviolet and infrared rays, which are not effectively used in solar cells, into effective wavelength of solar cell. We used fluoride $Na(Ca)YF_4$ phosphor for wavelength conversion. Then, a wavelength-conversion fluorescent paste, prepared using an organic-silicon binder, was used to prepare a film that was applied to Si solar cells. It was confirmed that conversion efficiency improved by 5% or more.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.77.2-77.2
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• 2013

In this talk, I will briefly review recent results of my group related to application of atomic layer deposition (ALD) for fabricating environmental catalysts and organic solar cells. ALD was used for preparing thin films of TiO2 and NiO on mesporous silica with a mean pore size of 15 nm. Upon depositing TiO2 thin films of TiO2 using ALD, the mesoporous structure of the silica substrate was preserved to some extent. We show that efficiency for removing toluene by adsorption and catalytic oxidation is dependent of mean thickness of TiO2 deposited on silica, i.e., fine tuning of the thickness of thin film using ALD can be beneficial for preparing high-performing adsorbents and oxidation catalysts of volatile organic compound. NiO/silica system prepared by ALD was used for catalysts of chemical conversion of CO2. Here, NiO nanoparticles are well dispersed on silica and confiend in the pore, showing high catalytic activity and stability at 800oC for CO2 reforming of methane reaction. We also used ALD for surface modulation of buffer layers of organic solar cell. TiO2 and ZnO thin films were deposited on wet-chemically prepared ZnO ripple structures, and thin films with mean thickness of ~2 nm showed highest power conversion efficiency of organic solar cell. Moreover, performance of ALD-prepared organic solar cells were shown to be more stable than those without ALD. Thin films of oxides deposited on ZnO ripple buffer layer could heal defect sites of ZnO, which can act as recombination center of electrons and holes.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.1-9
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• 2010

We are presenting an overview of a R&D trend on dye-sensitized solar cells and organic polymer solar cells, which are classified into a next-generation solar cell, and the perspective on their hybridization technology. When considering the competition with inorganic material-base solar cells, especially, these next-generation solar cells need a new hybridization technology, even though it is still at the initial stage. The fusion and hybridization of them will be not only attractive in a new application, but also promising to expect significant progresses in the near future for successful R&D.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2553-2559
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• 2011

Two novel quinacridone (QNC) dyes with thiophene or benzene-conjugated bridge and cyanoacrylic acid acceptor were first designed and synthesized for use in dye-sensitized solar cells (DSSCs). The absorption spectra, electrochemical and photovoltaic properties of these dyes were investigated. Under simulated AM 1.5G irradiation conditions, the solar cell based on the quinacridone dye containing thiophene as a bridge unit had a short-circuit photocurrent density of 8.51 $mA{\cdot}cm^{-2}$, an open-circuit voltage of 643.6 mV, and a fill factor of 0.70, corresponding to an overall conversion efficiency of 3.86%.