Browsing by Author "Ko, Chu-Jung"

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Method of microwave annealing for enhancing organic electronic devices
(2008-11-06)
Chen, Fang-Chung
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Ko, Chu-Jung
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Lin, Yi-Kai
A method of microwave annealing for enhancing the properties of organic electronic devices is provided, including the steps of providing organic electronic devices and then microwave annealing the organic electronic devices. Because microwave annealing is non-contact and requires only a short time for annealing, and also because it anneals a target selectively and may anneal only the organic active layer of organic electronic device, microwave annealing allows organic molecules in the organic active layer to be rearranged quickly, so as to improve the arrangement of the organic molecules, and this in turn elevates the quantum efficiency thereof and enhances the properties of the organic electronic devices.
Microwave annealing of polymer photovoltaic devices
(2007-11-05)
Ko, Chu-Jung
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Lin, Yi-Kai
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Chen, Fang-Chung
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光電工程學系
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Department of Photonics
A selective microwave irradiation annealing method for the preparation of efficient polymer photovoltaic devices is reported. The power conversion efficiency of the devices increases upon increasing the irradiation time. In situ temperature probing suggests that the microwaves could penetrate the anode without any loss of energy, whereas the organic active layer and the cathode were both heated. Furthermore, X-ray diffraction indicated that microwave annealing enhanced the degree of crystallization of the polymer chains.
Modified buffer layers for polymer photovoltaic devices
(2007-02-05)
Ko, Chu-Jung
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Lin, Yi-Kai
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Chen, Fang-Chung
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Chu, Chi-Wei
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光電工程學系
The influence of anode buffer layers on the performance of polymer photovoltaic devices based on blends of poly(3-hexylthiophene) and [6,6]-phenyl-C-61-buytyric acid methyl ester has been investigated. The buffer layers consist of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT-PSS) doped with different concentrations of mannitol. Improved power conversion efficiency, up to 5.2%, has been observed by reducing the resistance of PEDOT:PSS after doping. One extrapolation method has been developed to exclude the resistance from the connection of the electrodes from the total device resistance. The results confirm that the device improvement is due to the reduction of series resistance of the PEDOT:PSS after the mannitol doping. (c) 2007 American Institute of Physics.
Morphological study of P3HT:PCBM blend films prepared through solvent annealing for solar cell applications
(2010-12-01)
Chen, Fang-Chung
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Ko, Chu-Jung
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Wu, Jyh-Lih
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Chen, Wei-Chi
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光電工程學系
We have systematically investigated the morphology of poly(3-hexylthiophene: P3HT) and [6,6]-phenyl C(61)-butyic acid methyl ester (PCBM) blend films prepared through a slow growth apparoch as a function of PCBM loading in the blends for bulk heterojunction solar cells. In addition to the electrical characterisitcs, the molecular ordering and crystallinity of the polymers was examined by using the UV-vis spectroscopy and grazing incidence X-ray diffraction. From the images of confocal laser scan microscopy, we were also able to in-situ monitor the phase separation of the P3HT:PCBM blends during the process of solvent evaporation. Finally, the conductive atomic force microscopy was utilized to probe the spatial distribution of the local current across the photoactive layer prepared with various P3HT:PCBM ratios. From the experimental results, we found that the distribution of PCBM molecules in the P3HT matrix became homogeneous after the solvent annealing process, even though the distribution of the PCBM molecules was not even in the beginning. Therefore, the higher device efficiency could be attributed to the better thin-film morphology of the polymer blends. (C) 2010 Elsevier B.V. All rights reserved.
Organic active-layer solution for polymer solar cell and method for preparing the same
(2009-09-03)
Chen, Fang-Chung
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Tseng, Hsin-Chen
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Ko, Chu-Jung
An organic active-layer solution for a polymer solar cell and a method for preparing the same are provided, wherein the organic active-layer solution comprises an organic active-layer material, a first organic solvent and a second organic solvent. The first organic solvent has a boiling point ranging from 50° C. to 200° C. while the second organic solvent has a boiling point ranging from 150° C. to 300° C. The second organic solvent is added into the first organic solvent to dissolve the organic active-layer material. As the second organic solvent has a higher boiling point (a lower evaporation speed), it can directly lower an evaporation speed of the organic active-layer solution, thereby simplifying a manufacturing process of the polymer solar cell and increasing a power conversion efficiency of the polymer solar cell.
Polymer solar cell and manufacturing method thereof
(2008-06-26)
Chen, Fang-Chung
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Chu, Chih-Wei
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Ko, Chu-Jung
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Lin, Yi-Kai
A polymer solar cell and a manufacturing method thereof are disclosed. The cell includes a substrate, a first electrode located on top of the substrate, a conductive polymer layer having a conductive polymer and an additive located on the first electrode, a semiconductor layer over the conductive polymer layer and a second electrode over the semiconductor layer. The manufacturing method of the polymer solar cell is composed of following steps: growing a first electrode on a substrate; mixing an additive and a conductive polymer to form a mixture; depositing the mixture on the first electrode to form a conductive polymer layer; depositing a semiconductor layer on the conductive polymer layer and evaporating a second electrode on the semiconductor layer. By adding additive into the conductive polymer, resistance of the conductive polymer layer is reduced and efficiency of the cell is improved.
Self-organization of microlens arrays caused by the spin-coating-assisted hydrophobic effect
(2006-11-01)
Chen, Fang-Chung
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Huang, Wen-Kuei
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Ko, Chu-Jung
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光電工程學系
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顯示科技研究所
A simple, low-cost, low-temperature, and shape-controllable approach has been demonstrated to fabricate polymer microlens arrays (MLAs). By using microcontact printing of the self-assembled monolayers and then spin coating, the microlenses were able to organize themselves on the patterned glass substrate. High-quality MLAs made of NOA65 prepolymer with lens-diameters of 50, 75, and 100 pm have been fabricated by this method. Lens shapes can be controlled by changing the spin rates of the prepolymer coating. Optical measurements have revealed an excellent light-collecting capability from the fabricated MLAs. It is anticipated that the technique will be ideally suited to low-cost and high-volume production.
Solvent mixtures for improving device efficiency of polymer photovoltaic devices
(2008-03-10)
Chen, Fang-Chung
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Tseng, Hsin-Chen
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Ko, Chu-Jung
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光電工程學系
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顯示科技研究所
In this work, we used solvent mixtures, consisting of 1-chloronaphthalene (Cl-naph), one solvent with a high boiling point, and o-dichlorobenzene, to prepare the polymer films for polymer photovoltaic devices. Because of the lower vapor pressure of the solvent mixtures, the polymer films dried slower. With higher Cl-naph concentration in the organic solvent, the polymer chains had longer time to self-organize themselves. As a result, the higher degree of crystalline led to lower device series resistance, thereby increasing the performance of the photovoltaic devices. (c) 2008 American Institute of Physics.
Submicron-scale manipulation of phase separation in organic solar cells
(2008-01-14)
Chen, Fang-Chung
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Lin, Yi-Kai
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Ko, Chu-Jung
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光電工程學系
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顯示科技研究所
This paper describes a method for controlling the submicron-scale phase separation of poly(3-hexylthiophene) and (6,6)-phenyl-C(61)-butyric acid methyl ester in organic solar cells. Using microcontact printing of self-assembled monolayers on the device buffer layer to divide the surface into two regimes having different surface energies, an interdigitated structure aligned vertical to the substrate surface is achieved after spontaneous surface-directed phase separation. The power conversion efficiency increases upon decreasing the grating spacing, reaching 2.47%. The hole mobility increased as a consequence of improved polymer chain ordering, resulting in higher device efficiency, while smaller pattern sizes were used. (c) 2008 American Institute of Physics.