Browsing by Author "Chen, Peilin"

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Addressable Cell Microarrays via Switchable Superhydrophobic Surfaces
(2010)
Shiu, Jau-Ye
;
Kuo, Chiung Wen
;
Whang, Wha-Tzong
;
Chen, Peilin
;
材料科學與工程學系
Here we describe an approach to fabricate addressable cell microarrays, which are based on the patterned switchable superhydrophobic surfaces. The switchable superhydrophobic surfaces were prepared by roughening the surfaces of fluoropolymers on the electrodes. Upon the application of 150 V to the underneath electrodes, the water contact angle on the roughened fluoropolymer surfaces could be decreased from 163 degrees to less than 10 degrees allowing the deposition of fibronectin, which could guide the growth of the cells. Our result indicated that it was possible to control the spatial distribution of two different cells on the cell microarrays. (C) Koninklijke Brill NV, Leiden, 2010
Annealing effect of polymer bulk heterojunction solar cells based on polyfluorene and fullerene blend
(2009-02-01)
Huang, Jen-Hsien
;
Yang, Chuan-Yi
;
Ho, Zhong-Yo
;
Kekuda, Dhananjay
;
Wu, Meng-Chyi
Control of blend morphology at the nanoscale and high charge mobility is essential for polymer photovoltaic devices in terms of their power conversion efficiencies (PCE). In the case of bulk heterojunctions solar cells, both blend morphology and charge mobility are influenced by thermal treatment. In this manuscript, we study the effects of annealing temperature on polymer PV devices with blends of poly[9,9'-dioctyl-fluorene-co-bithiophene] (F8T2) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). The morphological changes of blended films were observed upon thermal annealing temperature near and above glass transition temperature (130 degrees C). Such microstructural transformations resulted in modified charge transport pathways and therefore greately influenced the device performance. The highest PCE of 2.14% with an open-circuit voltage (V(OC)) of 0.99 V and a short-circuit current (J(SC)) of 4.24 mA/cm(2) was achieved by device annealing at 70 degrees C for 20 min. (C) 2008 Elsevier B.V. All rights reserved.
Behavior of single DNA molecules in the well-ordered nanopores
(2008-10-03)
Shiu, Jau-Ye
;
Whang, Wha-Tzong
;
Chen, Peilin
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Here we describe a simple approach to fabricate robust three-dimensional periodic porous nanostructure inside the microchannels. In this approach, the colloidal crystals were first grown inside the microchannel using an evaporation-assisted self-assembly process. Then the void spaces among the colloidal crystals were filled with epoxy-based negative tone photoresist. After subsequent development and nanoparticle removal, the well-ordered nanoporous structures inside the microchannel could be fabricated. Depending on the size of the colloidal nanoparticles, periodic porous nanostructures inside the microchannels with cavity size of 330 and 570 nm have been obtained. The dimensions of interconnecting pores for these cavities were around 40 and 64 nm, respectively. The behavior of single X-phage DNA molecules in these nanoporous structures was studied using fluorescence microscopy. It was found that the length of DNA molecules oscillated in the nanoporous structures. The measured length for A-phage DNA was larger in the 330 nm cavity than those measured in the 570 nm cavity. (C) 2008 Elsevier B.V. All rights reserved.
Controlling vertical alignment of phthalocyanine nanofibers on transparent graphene-coated ITO electrodes for organic field emitters
(2012)
Huang, Kuo-Jung
;
Hsiao, Yu-Sheng
;
Huang, Jen-Hsien
;
Chu, Chih-Wei
;
Chen, Peilin
In this study, we developed a simple and efficient approach-using graphene coatings on ITO as transparent electrodes-for inducing the growth of 29H,31H-phthalocyanine (H2Pc) nanofiber arrays through a thermal evaporation process, with potential use in organic field emitters (FEs). By controlling the surface energy and temperature of the electrodes during evaporation, H2Pc molecules readily self-assemble, forming an out-of-plane morphology on reduced graphene oxide surfaces (rGO; surface energy: ca. 50 mJ m(-2)). The devices fabricated on rGO/indium tin oxide (FE-rGO) exhibited not only excellent FE performance but also outstanding anti-degradation capability during stability tests. This facile approach toward rGO coatings opens a new avenue for the transformation of small organic molecule films into vertically standing nanostructures on transparent electrodes, with various organic electronics applications.
Correlation between Exciton Lifetime Distribution and Morphology of Bulk Heterojunction Films after Solvent Annealing
(2010-05-20)
Huang, Jen-Hsien
;
Li, Kuang-Chieh
;
Chien, Fan-Ching
;
Hsiao, Yu-Sheng
;
Kekuda, Dhananjay
We have synthesized a low-bandgap polymer, bithiazole-based polymer (PCPDTTBT) containing cyclopentadithiophene and thiophene units, and studied its opticophysical properties and morphologies in bulk heterojunction films after annealing. We used confocal optical microscopy in conjunction with a fluorescence module to record exciton lifetime images within photoactive layers of PCPDTTBT and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). These images, which were consistent with those recorded using atomic force microscopy and transmission electron microscopy, revealed that phase separation of PCPDTTBT and PCBM occurred during slow solvent evaporation. This phase separation not only provided bicontinuous pathways for carrier transport to the respective electrodes hut also enhanced the degree of polymer chain stacking, thereby improving the absorption and balancing the electron and hole mobilities. We tested the performance of solar cells incorporating PCPDTTBT and various fullerene derivatives. Under AM 1.5 G illumination (100 mW cm(-2)), a PCPDTTBT/bisPCBM-based solar cell exhibited a power conversion efficiency of 3.8%, with a short circuit current of 7.3 mA cm(-2), an open circuit voltage of 0.88 V, and a fill factor of 59.1%.
Dual-color electrochromic films incorporating a periodic polymer nanostructure
(2012)
Wei, Hung-Yu
;
Hsiao, Yu-Sheng
;
Huang, Jen-Hsien
;
Hsu, Chih-Yu
;
Chang, Feng-Chih
In this study, we used electrochemical deposition with a polystyrene (PS) bead template to prepare thin layers of poly(3,4-ethylenedioxythiophene) (PEDOT) that has a nanometer-scale honeycomb periodicity. To achieve dual-color electrochromic films, we then used pulsed electrochemical deposition to form polyaniline (PANI) layers on the rims of the PEDOT honeycomb film. Modifying the depositing charge density of PANI allowed tuning of the color of the composite films. We estimated the coloration efficiencies with respect to the values expected for corresponding amounts of pristine single layers of PEDOT and PANI. As a result of improved contact between the polymer film and the electrolyte, the coloration efficiencies of the structured composite films were much closer to their theoretical values than those of the corresponding bilayer composite films. Moreover, the switching times of the structured composite films were much faster than those of the bilayer composite films prepared without the nanostructures.
Functionalized silver nanowires for live cell study
(2008-06-05)
Kuo, Chiung-Wen
;
Shiu, Jau-Ye
;
Wei, Kung Hwa
;
Chen, Peilin
;
材料科學與工程學系
The biocompatibility of the surface-functionalized silver nanowires has been investigated in two cell lines. It was found that the functionalized silver nanowires with 200 nm diameter and length up to a few mu m can be internalized by cells. The cytotoxicity of the silver nanowires was found to depend on their surface modifications. It was also demonstrated that the surface-enhanced Raman scattering (SERS) could be measured on the silver nanowires, which added additional functionality to the silver nanowires.
Humidity-switch chromism of aniline-pentamer in Nafion
(2016-08-19)
Lin, Yen-Hao
;
Hsiao, Yu-Sheng
;
Lu, Hsiao-Chi
;
Chen, Peilin
;
Whang, Wha-Tzong
Aniline-pentamer (AP) in Nafion triggered with humidity content displays an interesting chromism from blue to pink, which is much wider of color shift than general polyaniline. Thermogravimetric analysis confirms the reversal color change related to the moisture content in the sample. IR absorption spectra make known AP having high degree of protonation at lower water content. UV-Vis absorption expose the chromism process having something more than just protonation. The change of electronic energy levels and PL spectra reveal that there must be a complex interaction in NaAP. Raman scattering mapping confirms that drying causes the - SO3- hydrophilic channels transforming to isolated domains dispersed in matrix, which induces heavy protonation and complexation of AP with - SO3- groups. We can infer that the interesting humidity-switch chromism is due to the reversible protonation/deprotonation as well as complexation of AP with - SO3- groups through the reversible change of Nafion\'s morphology.
Improving the Light Trapping Efficiency of Plasmonic Polymer Solar Cells through Photon Management
(2012-10-04)
Hsiao, Yu-Sheng
;
Charan, Shobhit
;
Wu, Feng-Yu
;
Chien, Fan-Ching
;
Chu, Chih-Wei
In this study, we have explored how light trapping efficiency can be enhanced by using gold nanoparticles (Au NPs) of various sizes and shapes on the front of polymer solar cells (PSCs) with the active layer-blends of poly(3-hexyl thiophene) and [6,6]-phenyl-C-61-butyric acid methyl ester. The light-concentrating behavior was enhanced after we had incorporated gold nanospheres or nanorods into the anodic buffer layer [based on poly(3,4-ethylenedioxythiophene):polystyrenesulfonate] to trigger various localized surface plasmon resonance (LSPR) bands. Comparison of the optical characteristics and the performance of the PSCs prepared with and without Au NPs, and we found that the UV-vis and wavelength-dependent photoluminescent spectral data corroborated with the device performance due to the photon management by considering the light scattering and LSPR effects at the active layer. The presence of Au NPs increased the power conversion efficiency to approximately 4.3% (an enhancement of 24%).
Improving the Light Trapping Efficiency of Plasmonic Polymer Solar Cells through Photon Management
(2012-10-04)
Hsiao, Yu-Sheng
;
Charan, Shobhit
;
Wu, Feng-Yu
;
Chien, Fan-Ching
;
Chu, Chih-Wei
In this study, we have explored how light trapping efficiency can be enhanced by using gold nanoparticles (Au NPs) of various sizes and shapes on the front of polymer solar cells (PSCs) with the active layer-blends of poly(3-hexyl thiophene) and [6,6]-phenyl-C-61-butyric acid methyl ester. The light-concentrating behavior was enhanced after we had incorporated gold nanospheres or nanorods into the anodic buffer layer [based on poly(3,4-ethylenedioxythiophene):polystyrenesulfonate] to trigger various localized surface plasmon resonance (LSPR) bands. Comparison of the optical characteristics and the performance of the PSCs prepared with and without Au NPs, and we found that the UV-vis and wavelength-dependent photoluminescent spectral data corroborated with the device performance due to the photon management by considering the light scattering and LSPR effects at the active layer. The presence of Au NPs increased the power conversion efficiency to approximately 4.3% (an enhancement of 24%).
Monitoring the 3D Nanostructures of Bulk Heterojunction Polymer Solar Cells Using Confocal Lifetime Imaging
(2010-03-01)
Huang, Jen-Hsien
;
Chien, Fan-Ching
;
Chen, Peilin
;
Ho, Kuo-Chuan
;
Chu, Chih-Wei
In this study, the exciton lifetime images within the photoactive layers of poly(3-hexylthiophene) (P3HT) kind [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are revealed by confocal optical microscopy combined with the fluorescence module. The images reveal that the active layers during slow solvent evaporation provide 3D pathways for charge transport and the concentration gradient through the film which reflects the better cell performance. This technique offers a great help to investigate the 3D optical-physical property without destroying the blends.
Monolithic integration of well-ordered nanoporous structures in the microfluidic channels for bioseparation
(2007-08-31)
Kuo, Chiung-Wen
;
Shiu, Jau-Ye
;
Wei, Kung Hwa
;
Chen, Peilin
;
材料科學與工程學系
Gel electrophoresis and capillary gel electrophoresis are widely used for the separation of biomolecules. With increasing demand in the miniaturized devices such as lab-on-a-chip, it is necessary to integrate such a separation component into a chip format. Here, we describe a simple approach to fabricate robust three-dimensional periodic porous nanostructures inside the microchannels for the separation of DNA molecules. In our approach, the colloidal crystals were first grown inside the microchannel using evaporation assisted self-assembly process. Then the void spaces among the colloidal crystals were filled with epoxy-based negative tone photoresist (SU-8). UV radiation was used to cure the photoresist at the desired area inside the microchannel. After subsequent development and nanoparticle removal, the well-ordered nanoporous structures inside the microchannel were obtained. Our results indicated that it was possible to construct periodic porous nanostructures inside the microchannels with cavity size around 300 nm and interconnecting pores around 30 nm. The mobility of large DNA molecules with different sizes was measured as a function of the applied electric field in the nanoporous materials. It was also demonstrated that I kilo-base pair (kbp) DNA ladders could be separated in such an integrated system within 10 min under moderate electric field. (c) 2007 Published by Elsevier B.V.
Nanofluidic system for the studies of single DNA molecules
(2008-07-01)
Kuo, Chiung-Wen
;
Wei, Kung Hwa
;
Lin, Chun-Hsun
;
Shiu, Jau-Ye
;
Chen, Peilin
Here, we describe a simple and low-cost lithographic technique to fabricate size-controllable nanopillar arrays inside the microfluidic channels for the studies of single DNA molecules. in this approach, nanosphere lithography has been employed to grow a single layer of well-ordered close-packed colloidal crystals inside the microfluidic channels. The size of the polymeric colloidal nanoparticles could be trimmed by oxygen plasma treatment. These size-trimmed colloidal nanoparticles were then used as the etching mask in a deep etching process. As a result, well-ordered size-controllable nanopillar arrays could be fabricated inside the microfluidic channels. The gap distance between the nanopillars could be tuned between 20 and 80 nm allowing the formation of nanofluidic system where the behavi of of a single lambda-phage DNA molecule has been investigated. It was found that the lambda-phage DNA molecule could be fully stretched in the nanofluidic system formed by nanopillars with 50 nm gap distance at a field of 50 V/cm.
Nanoscale Correlation between Exciton Dissociation and Carrier Transport in Silole-Containing Cyclopentadithiophene-Based Bulk Heterojunction Films
(2011-02-10)
Huang, Jen-Hsien
;
Teng, Chin-Min
;
Hsiao, Yu-Sheng
;
Yen, Feng-Wen
;
Chen, Peilin
Understanding the effects of conjugated polymer structures on exciton lifetimes and morphologies within bulk heterojunction (BHJ) films is a necessary step toward the development of better organic solar cells. Studying the impact of a polymer's structure on the optical, morphological, and performance characteristics of a device can lead to advances in the design of new polymers. In this study, we synthesized carbon- and silicon-bridged cyclopentadithiophene- (CPDT-) based polymers and determined their photophysical properties and morphologies by measuring the exciton lifetime distributions in their BHJ films The silicon-bridged CPDT-based polymer/[6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) BHJ exhibited a higher degree of luminescence quenching, suggesting that thermodynamically favorable mixing on the molecular scale and nanoscale phase separation occurred simultaneously in the blend film. We attribute this favorable morphology to the presence of strong pi-pi stacking in the silicon-bridged CPDT-based polymers. Under AM 1.5 G illumination (100 mA cm(-2)), a device incorporating the silicon-bridged CPDT-based polymer and PCBM (1:2, w/w) gave an overall power conversion efficiency of 3.5% with a short-circuit current of 9.0 mA cm(-2), an open-circuit voltage of 0.72 V, and a fill factor of 53.6%.
Observation of enhanced cell adhesion and transfection efficiency on superhydrophobic surfaces
(2010)
Shiu, Jau-Ye
;
Kuo, Chiung-Wen
;
Whang, Wha-Tzong
;
Chen, Peilin
;
材料科學與工程學系
It was found that cells attached preferentially on the roughened area of patterned superhydrophobic surfaces allowing the formation of cell microarrays with the advantages of improved cell adhesion, natural separation of colonies and enhanced transfection efficiency.
Organic Photovoltaics and Bioelectrodes Providing Electrical Stimulation for PC12 Cell Differentiation and Neurite Outgrowth
(2016-04-13)
Hsiao, Yu-Sheng
;
Liao, Yan-Hao
;
Chen, Huan-Lin
;
Chen, Peilin
;
Chen, Fang-Chung
Current bioelectronic medicines for neurological therapies generally involve treatment with a bioelectronic system comprising a power supply unit and a bioelectrode device. Further integration of wireless and self-powered units is of practical importance for implantable bioelectronics. In this study, we developed biocompatible organic photovoltaics (OPVs) for serving as wireless electrical power supply units that can be operated under illumination with near-infrared (NIR) light, and organic bioelectronic interface (OBEI) electrode devices as neural stimulation electrodes. The OPV/OBEI integrated system is capable to provide electrical stimulation (ES) as a means of enhancing neuron-like PC12 cell differentiation and neurite outgrowth. For the OPV design, we prepared devices incorporating two photoactive material systems-beta-carotene/N,N\'-dioctyl-3,4,9,10-perylenedicarboximide (beta-carotene/PTCDI-C8) and poly(3-hexylthiophene)/phenyl-C-61-butyric acid methyl ester (P3HT/PCBM)-that exhibited open circuit voltages of 0.11 and 0.49 V, respectively, under NIR light LED (NLED) illumination. Then, we connected OBEI devices with different electrode gaps, incorporating biocompatible poly(hydroxymethylated-3,4-ethyl-enedioxythiophene), to OPVs to precisely tailor the direct current electric field conditions during the culturing of PC12 cells. This NIR light-driven OPV/OBEI system could be engineered to provide tunable control over the electric field (from 220 to 980 mV mm(-1)) to promote 64% enhancement in the neurite length, direct the neurite orientation on chips, or both. The OPV/OBEI integrated systems under NIR illumination appear to function as effective power delivery platforms that should meet the requirements for wirelessly offering medical ES to a portion of the nervous system; they might also be a key technology for the development of next-generation implantable bioelectronics.
Performance of chromophore-type electrochromic devices employing indium tin oxide nanorod optical amplification
(2012-03-01)
Huang, Jen-Hsien
;
Hsu, Min-Hsiang
;
Hsiao, Yu-Sheng
;
Chen, Peilin
;
Yu, Peichen
In this study, we used transparent and conductive indium tin oxide (ITO) nanorods, prepared through electron-beam evaporation onto ITO glass substrates, as electrodes for viologen-based electrochromic devices (ECDs). Although the shapes of these ITO nanorods could be controlled simply by manipulating the evaporation time, they always maintained their high optical transmittance. Scanning electron microscopy images revealed that the ITO rods were uniformly distributed on the ITO glass: they had large surface areas for the tethering of electrochromic molecules. As a result, the ITO nanorods functioned as optical amplifiers in the viologen-based ECDs, increasing the color contrast [Delta T (%)] from 38% to 61%. (C) 2011 Elsevier B.V. All rights reserved.
Studies of surface-modified gold nanowires inside living cells
(2007-12-17)
Kuo, Chiung-Wen
;
Lai, Ain-Jung
;
Wei, Kung Hwa
;
Chen, Peilin
;
材料科學與工程學系
The cytotoxicity of various surface-functionalized gold nanowires with different aspect ratios is investigated by (3-(4,5-di-me thylthiazol-2-yl)2,5-diphenyltetrazolium bromide) (MTT) assays for two cell lines, fibroblast and HeLa. It is found that functionalized gold nanowires with a diameter of 200 nm and lengths up to a few micrometers can be readily internalized by both types of cells regardless of the type of surface functionalization. However, the cytotoxicity of the gold nanowires is observed to depend on their surface modification. Serum-coated gold nanowires are the least toxic, whereas more than 50% of the cells are damaged in the presence of mercapto-acid-modified gold nanowires even at very low concentrations (10(3) nanowiresmL(-1)). Nanowires with different aspect ratios exhibit the same cytotoxicity within limits of experimental error. However, the uptake efficiency is found to be higher for shorter nanowires as compared to their longer counterparts. Therefore, we conclude that internalized nanowires with high aspect ratios are more toxic to cells than nanowires with low aspect ratios. Positively charged aminothiol-modified gold nanowires are employed to deliver both plasmid DNA and probe molecules into cells without compromising the viability of the cells. The local environment of individual nanowires within the cells is studied by monitoring the fluorescence signal from probe molecules attached to the nanowires.
Superhydrophobic Coatings for Microdevices
(2008)
Shiu, Jau-Ye
;
Whang, Wha-Tzong
;
Chen, Peilin
;
材料科學與工程學系
;
Department of Materials Science and Engineering
We have developed two simple techniques to impart superhydrophobic properties to the surfaces of microdevices. In the first approach, thin films of a fluoropolymer were spin-coated on the device surfaces followed by an oxygen plasma treatment. By varying the oxygen plasma treatment time, the water contact angles on device surface could be tuned from 120 degrees to 169 degrees. In the second approach, a nanoimprint process was used to create nanostructures on the devices. To fabricate nanoimprint stamps with various feature sizes, nanosphere lithography was employed to produce a monolayer of well-ordered close-packed nanoparticle array on the silicon surfaces. After oxygen plasma trimming, metal deposition and dry etching process, silicon stamps with different nanostructures were obtained. These stamps were used to imprint nanostructures on hydrophobic coatings, such as Teflon, over the device surfaces. The water contact angle as high as 167 degrees was obtained by the second approach. (c) Koninklijke Brill NV, Leiden, 2008
Surface modified gold nanowires for mammalian cell transfection
(2008-01-16)
Kuo, Chiung-Wen
;
Lai, Jun-Jung
;
Wei, Kung Hwa
;
Chen, Peilin
;
材料科學與工程學系
Aminothiol modified gold nanowires have been used as vectors for the delivery of plasmid DNA into two different types of mammalian cells: 3T3 and HeLa. It was measured that positively charged gold nanowires with a diameter of 200 nm and a length around 5 mu m were capable of carrying 1 pg of plasmid DNA per nanowire into cells. Compared with other transfection reagents, the gold nanowires exhibited the highest transfection efficiency while almost no cytotoxicity was observed. In addition, it has been shown that individual nanowires can be visualized with sub-micrometer resolution, which may allow the use of functionalized multi-segment nanowires as local probes for the investigation of the microenvironment inside cells.