Browsing by Author "Ko, Fu-Hsiang"

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A flexible and miniaturized hair dye based photodetector via chemiluminescence pathway
(2017-04-15)
Lin, Ching-Chang
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Sun, Da-Shiuan
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Lin, Ya-Lin
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Tsai, Tsung-Tso
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Cheng, Chieh
A flexible and miniaturized metal semiconductor metal (MSM) biomolecular photodetector was developed as the core photocurrent system through chemiluminescence for hydrogen peroxide sensing. The flexible photocurrent sensing system was manufactured on a 30-mu m-thick crystalline silicon chip by chemical etching process, which produced a flexible silicon chip. A surface texturization design on the flexible device enhanced the light-trapping effect and minimized reflectivity losses from the incident light. The model protein streptavidin bound to horseradish peroxidase (HRP) was successfully immobilized onto the sensor surface through high-affinity conjugation with biotin. The luminescence reaction occurred with luminol, hydrogen peroxide and HRP enzyme, and the emission of light from the catalytic reaction was detected by underlying flexible photodetector. The chemiluminescence in the miniaturized photocurrent sensing system was successfully used to determine the hydrogen peroxide concentration in real-time analyses. The hydrogen peroxide detection limit of the flexible MSM photodetector was 2.47 mM. The performance of the flexible MSM photodetector maintained high stability under bending at various bending radii. Moreover, for concave bending, a significant improvement in detection signal intensity (14.5% enhancement compared with a flat configuration) was observed because of the increased photocurrent, which was attributed to enhancement of light trapping. Additionally, this detector was used to detect hydrogen peroxide concentrations in commercial hair dye products, which is a significant issue in the healthcare field. The development of this novel, flexible and miniaturized MSM biomolecular photodetector with excellent mechanical flexibility and high sensitivity demonstrates the applicability of this approach to future wearable sensor development efforts.
A highly sensitive and selective cyanide detection using a gold nanoparticle-based dual fluorescence-colorimetric sensor with a wide concentration range
(2016-05)
Cheng, Chieh
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Chen, Hsueh-Yang
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Wu, Chung-Shu
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Meen, Jagan Singh
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Simon, Turibius
In this study, a simple analytical system is presented for the detection of cyanide with a wide concentration range, which is respectively based on the fluorescent and colorimetric properties of gold nanoparticles. This dual-functional system can work directly for aqueous medium and expand efficiently a wide detection range over three orders of magnitudes for cyanide determination. By using the fluorescence method, the lowest concentration for quantification of cyanide ions is 1.0 x 10(-7) M, and the sensitivity is good enough for the determination of cyanide in drinking water. To recognize higher concentration of cyanide for industrial sewage monitoring, the colorimetric behavior can be used as an alternating tool for field tests from naked eye. The system also provides an excellent selectivity toward cyanide over other common interfering anions and metal ions, thus enabling the ability to monitor cyanide contamination in environmental samples. Furthermore, several real water samples spiked with cyanide, including local tap water, drinking water, lake water, and sea water, were analyzed, and the experimental results demonstrated that this sensing system exhibited excellent recoveries for these practical water samples. Our attempt may provide a cost-effective, rapid and simple solution for the recognition and determination of different levels of cyanide contamination in aqueous samples. (C) 2015 Elsevier B.V. All rights reserved.
A Nanodot Array Modulates Cell Adhesion and Induces an Apoptosis-Like Abnormality in NIH-3T3 Cells
(2009-08-01)
Pan, Hsu-An
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Hung, Yao-Ching
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Su, Chia-Wei
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Tai, Shih-Ming
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Chen, Chiun-Hsun
Micro-structures that mimic the extracellular substratum promote cell growth and differentiation, while the cellular reaction to a nanostructure is poorly defined. To evaluate the cellular response to a nanoscaled surface, NIH 3T3 cells were grown on nanodot arrays with dot diameters ranging from 10 to 200 nm. The nanodot arrays were fabricated by AAO processing on TaN-coated wafers. A thin layer of platinum, 5 nm in thickness, was sputtered onto the structure to improve biocompatibility. The cells grew normally on the 10-nm array and on flat surfaces. However, 50-nm, 100-nm, and 200-nm nanodot arrays induced apoptosis-like events. Abnormality was triggered after as few as 24 h of incubation on a 200-nm dot array. For cells grown on the 50-nm array, the abnormality started after 72 h of incubation. The number of filopodia extended from the cell bodies was lower for the abnormal cells. Immunostaining using antibodies against vinculin and actin filament was performed. Both the number of focal adhesions and the amount of cytoskeleton were decreased in cells grown on the 100-nm and 200-nm arrays. Pre-coatings of fibronectin (FN) or type I collagen promoted cellular anchorage and prevented the nanotopography-induced programed cell death. In summary, nanotopography, in the form of nanodot arrays, induced an apoptosis-like abnormality for cultured NIH 3T3 cells. The occurrence of the abnormality was mediated by the formation of focal adhesions.
A new biodegradable gate dielectric material based on keratin protein for organic thin film transistors
(2017-05-01)
Singh, Ranjodh
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Lin, Yen-Ting
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Chuang, Whae-Ling
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Ko, Fu-Hsiang
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材料科學與工程學系
By virtue of the biocompatibility, environmental benignity, and sustainability, as well as low cost of keratin protein's source herein, we report its application as a gate dielectric material for organic electronic devices. Keratin protein, which is a biodegradable material was directly extracted from poultry chicken feathers (CFs). Solution-processed regioregular poly(3-hexylthiophene) (P3HT) organic thin film transistors (OTFTs) with keratin dielectric thin film exhibited enhanced charge mobility of 2.293-10(-3) cm(2) V-1 s(-1) (saturation regime), high on-off current ratio of 105 and low threshold voltage, -1V as compared to conventional SiO2 dielectric. All the fabrication processes were performed below 100 degrees C. A detailed semiconductor-dielectric interface study has revealed that the high content of beta-sheet structure in keratin protein has guided the P3HT polymer chains, through supramolecular forces of interaction to form 2D nanoribbons of large crystallite size (150 nm) over keratin thin film. This has led to the reduced trapping sites at the semiconductor/dielectric interface and hence the enhanced electrical performance of OTFTs was observed. Atomic force microscopy (AFM) and Grazing Incidence X-ray diffraction (GI-XRD) study was further employed to explore the mechanism of formation of 2D nanoribbons of P3HT. The primary and secondary structure of keratin protein as analyzed by AFM, Transmission electron microscopy (TEM) and Fourier transform spectroscopy (FTIR) is also provided in this study. The water compatible nature of keratin has helped to overcome the common issue of dielectric layer washing that occurs mostly during fabrication of OTFTs by sol-gel method. The biodegradable nature of keratin protein has also been demonstrated here by providing it as feed to fishes in an aquarium. (C) 2017 Elsevier B. V. All rights reserved.
A new organic/inorganic electroluminescent material with a silsesquioxane core
(2009-04-01)
Cheng, Chih-Chia
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Chien, Chen-Han
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Yen, Ying-Chieh
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Ye, Yun-Sheng
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Ko, Fu-Hsiang
This paper describes a new polyhedral oligomeric silsesquioxane (POSS)-based blue-light electroluminescent nanoparticle, octakis[N-(9-ethyl-9-H-carbazol-3-yl)undecanamide-11-dimethylsiloxy]silsesquioxane (POSS-C11-Cz), which contains eight carbazole chromophore arms, synthesized through the hydrosilation reaction of octakis(dimethylsiloxy)silsesquioxane with the terminal olefin Cz-C11ene. POSS-C11-Cz exhibits good thermal and electrochemical stabilities and good film-forming properties. The optical and photoluminescence spectra of POSS-C11-Cz in solution and in the solid state indicate a reduction in the degrees of aggregation and excimer formation because inter-chain interactions were prohibited by the bulky POSS core. Moreover, photoluminescence spectra of a POSS-C11-Cz (3 wt.%,)/polyfluorene (97 blend revealed that the color was stable after heating the sample at 200 degrees C for 5 h; in contrast, the pure polyfluorene exhibited a significant green emission at 530 nm. A triple-layer device based on this blend exhibited higher maximum brightness and luminance efficiencies relative to those of the pure polyfluorene. Thus, the organic/inorganic POSS-C11-Cz/polyfluorene blend has potential for use in polymeric light-emitting diodes because of its improved thermal and optoelectronic characteristics. Published by Elsevier Ltd on behalf of Acta Materialia Inc.
A new supramolecular film formed from a silsesquioxane derivative for application in proton exchange membranes
(2012-01-14)
Cheng, Chih-Chia
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Yen, Ying-Chieh
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Ko, Fu-Hsiang
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Chu, Chih-Wei
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Fan, Shih-Kang
A new polyhedral oligomeric silsesquioxane ionomer (HO-doped PUSS-C11-Py) has been investigated. This new ionomer is able to self-assemble through macromers by quadruple hydrogen bonding interactions into a physically crosslinked polymer-like material that can be easily fabricated into films with micro-phase separation. This HCl-doped POSS-C11-Py membrane exhibits higher proton conductivity than a typical Nafion membrane at high temperature, which is extremely rare for a non-sulfonic acid system. This newly developed material may provide an alternative route toward design and fabrication of a new type of proton exchange membranes.
A rapid and portable sensor based on protein-modified gold nanoparticle probes and lateral flow assay for naked eye detection of mercury ion
(2012-09-01)
Chao, Cheng-Han
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Wu, Chung-Shu
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Huang, Chung-Chih
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Liang, Jie-Chian
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Wang, Hsiao-Ting
Contamination of the environment with heavy metal ions has been an important worldwide concern for decades. Among them, mercury ion (Hg2+) is one of the heavy metal ion maintained in the detection because of its toxicity. In this study, we have designed the gold nanoparticle (AuNP) probes of carboxylic modified protein and employed the lateral flow assay to detect the Hg2+ without complicated instrumentations and technical expertise. The captured AuNP probes on the test zone and control zone of the sensor produced the characteristic red bands, enabling visual discrimination of Hg2+ concentrations. The demand of Hg2+ analysis in environmental applications requires parallel analytical strategies; such a method with simplicity and rapidity has enormous potential for the application of Hg2+ monitoring in environment, water, and food samples. (C) 2012 Elsevier B.V. All rights reserved.
A Robust Data Retention Characteristic of Sol-Gel-Derived Nanocrystal Memory by Hot-Hole Trapping
(2010-07-01)
Wu, Chi-Chang
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Ko, Fu-Hsiang
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Yang, Wen-Luh
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You, Hsin-Chiang
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Liu, Fu-Ken
A new sol-gel-derived Ti(x)Zr(y)Si(z)O nanocrystal (NC) memory with a high-performance data retention characteristic is demonstrated by the hot-hole-trapping method. Prior to rapid thermal annealing, the high-density NC layer is formed by depositing a well-mixed solution of titanium tetrachloride, silicon tetrachloride, and zirconium tetrachloride. The electrical properties of the sol-gel-derived NC memory are demonstrated in terms of memory window, charge retention, program speed, and endurance. The memory window of the NC memory from the novel hot-hole-trapping mechanism can be achieved up to 4.18 +/- 0.21 V, and long retention times obtained from extrapolation up to 10(6) s are observed as 8%, 13%, and 21% window narrowing under respective temperatures of 25 degrees C, 85 degrees C, and 125 degrees C. The good electrical performance is attributed to the contribution of the high density of isolated NCs and hole-trapped into the deep-trap energy level, so no significant lateral and vertical charge leakage occurs.
A simple pyrene based AIEE active schiff base probe for selective naked eye and fluoresence off-on detection of trivalent cations with live cell application
(2016-08)
Simon, Turibius
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Shellaiah, Muthaiah
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Srinivasadesikan, Venkatesan
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Lin, Ching-Chang
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Ko, Fu-Hsiang
A simple pyrene based schiff base derivative 2-((pyren-1-ylmethylene)amino)ethanol (PE) has been synthesized via one-pot reaction and its nano-aggregation induced emission enhancement (AIEE) was reported through UV/PL, TEM and DLS studies. Interestingly, PE in CH3CN revealed the naked eye and fluorescence turn-on sensing responses towards Fe3+, Cr3+ and Al3+ ions, by means of PET and PE-PE* excimer formation. The 2:1 stoichiometry of sensor complexes PE-M3+ (M=Fe/Cr/Al) were calculated from Job\'s plots based on UV-vis absorption titrations and supported by FTIR and ESI (+Ve) mass analysis. In addition, the binding site of PE-M3+ sensor complexes was well established by H-1 NMR titrations and its sensor reversibility was recognized during subsequent addition of M3+ ions and PMDTA, respectively. The detection limits (LODs) and the association constant (K-a) values of PE-M3+ complexes were calculated by standard deviation and linear fittings. Likewise, quantum yield (Phi(f)) calculations, TEM analysis, pH effect and density functional theory (DFT) studies were executed for the PE-M3+ sensor complexes. More importantly, confocal fluorescence microscopy imaging in Raw264.7 cells showed that PE could be used as an effective fluorescent probe for detecting Fe3+, Cr3+ and Al3+ ions in living cells. (C) 2016 Elsevier B.V. All rights reserved.
An Affordable Wet Chemical Route to Grow Conducting Hybrid Graphite-Diamond Nanowires: Demonstration by A Single Nanowire Device
(2017-09-11)
Shellaiah, Muthaiah
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Chen, Tin Hao
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Simon, Turibius
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Li, Liang-Chen
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Sun, Kien Wen
We report an affordable wet chemical route for the reproducible hybrid graphite-diamond nanowires (G-DNWs) growth from cysteamine functionalized diamond nanoparticles (ND-Cys) via pH induced self-assembly, which has been visualized through SEM and TEM images. Interestingly, the mechanistic aspects behind that self-assembly directed G-DNWs formation was discussed in details. Notably, above self-assembly was validated by AFM and TEM data. Further interrogations by XRD and Raman data were revealed the possible graphite sheath wrapping over DNWs. Moreover, the HR-TEM studies also verified the coexistence of less perfect sp(2) graphite layer wrapped over the sp3 diamond carbon and the impurity channels as well. Very importantly, conductivity of hybrid G-DNWs was verified via fabrication of a single G-DNW. Wherein, the better conductivity of G-DNW portion L2 was found as 2.4 +/- 1.92 x 10(-6) mS/cm and revealed its effective applicability in near future. In addition to note, temperature dependent carrier transport mechanisms and activation energy calculations were reported in details in this work. Ultimately, to demonstrate the importance of our conductivity measurements, the possible mechanism behind the electrical transport and the comparative account on electrical resistivities of carbon based materials were provided.
An enzymatic kinetics investigation into the significantly enhanced activity of functionalized gold nanoparticles
(2008)
Wu, Chung-Shu
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Wu, Chia-Tien
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Yang, Yuh-Shyong
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Ko, Fu-Hsiang
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材料科學與工程學系
Kinetic and thermodynamic studies reveal that the property of significantly enhanced catalytic activity with colloidal stability is attributed to an efficacious means of tuning enzyme-substrate association by varying with the rate constants in the presence of functionalized gold nanoparticles.
ANYL 207-Miniaturized chemiluminescent photocurrent system for biomolecular sensing
(2009-08-16)
Chu, Min-Ching
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Lin, Ching-Chang
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Lin, Chie-Chieh
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Ko, Fu-Hsiang
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材料科學與工程學系奈米科技碩博班
Application of physical vapor deposition process to modify activated carbon fibers for ozone reduction
(2008-05-01)
Lin, Yu-Chih
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Chang, Chung-Liang
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Lin, Tser-Sheng
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Bai, Hsunling
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Yan, Ming-Gu
This study utilized the activated carbon fiber (ACF) modified with metal catalyst via physical vapor deposition (PVD) process (ACF/PVD) to diminish ozone. Furthermore, the ozone removal efficiency of ACF/PVD was compared with that of original ACF and ACF modified with metal catalyst via impregnation process (ACF/impregnation). In addition to the kinds of coated metal and the inlet ozone concentrations, the effects of the coating thickness and the reaction temperature on ACF/PVD for ozone removal were also examined. The results indicate that the ozone removal efficiency of ACF/PVD is better than that of original ACF and ACF/impregnation. The ozone removal efficiency of different metal-coated ACF/PVD in the superior order is gold (Au), and manganese (Mn). The increase of Au-coated thickness (3 nm to 80 nm) on ACF/PVD will enhance the ozone removal. However, when the Mn-coated thickness on ACF/PVD is larger than 15 rim, the ozone removal efficiency displays a declining trend. Furthermore, a higher reaction temperature will result in a better ozone removal of ACF/PVD and the original ACF.
Applying Dielectrophoresis on Silver Nanowires Alignment and Assembly to Enhance the Efficiency of Plasmonic Silicon Solar Cells
(2015-09-01)
Lin, Ching-Chang
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Wang, Szu-Yu
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Lin, Wei-Ling
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Lin, Ya-Lin
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Cheng, Chieh
The enhancement effects for solar cell are examined on the plasmonic properties of Ag nanowires (AgNWs) arrays, which fabricated by dielectrophoresis techniques. AgNWs in 100 nm diameters with aspect ratio (AR) of 100 were assembled into an array between the micrometer spaced electrodes by applying an AC electric field. The simulating results show that the array AgNWs can enhance the localized surface electric field on the silicon surface efficiently. Since, the incident lights can be scattered and trapped in the silicon layers which improves the enhancement of the external quantum efficiency. The optimized result of alignment of AgNWs average angle are 89.17 degree to the electrode edges and 21.98 degree of standard deviation under 100 Vpp, 250 kHz. In addition, the reflectance is 18.4% lower than those without AgNWs ones. The optimized plasmonic solar cells increase efficiency from 7.78% to 8.72%.
Aptamer based surface enhanced Raman scattering detection of adenosine using various core sizes of Au-Ag core-shell nanoparticles
(2014-01-01)
Ko, Fu-Hsiang
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Chang, Yu-Cheng
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材料科學與工程學系
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Department of Materials Science and Engineering
The present study synthesizes different sizes of Au nanoparticles (NPs) by adjusting the concentration of citrate. This method produces Au NPs with uniform sizes that can be used to grow Au-Ag core-shell NPs by the seeding growth method. We report the fabrication of monolayer Au NPs or Au-Ag core-shell NPs through the self-assembly of NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. The results indicate that the self-assembly time of Au NPs or Au-Ag core-shell NPs plays a crucial role in determining the surface coverage of NPs on the silicon substrate. The appropriate sizes of Au NPs or Au-Ag core-shell NPs were optimized to yield the greatest SERS effect in the rhodamine B molecule. The substrates with self-assembled Au-Ag core-shell NPs can also be used to detect adenosine by a structure-switch aptamer. The combination of Au-Ag core-shell NPs and DNA-based adenosine sensors provides a facile, high enhancement, low detection limit (0.1 nM) and low cost fabrication, which shall be of significant value for practical applications of other aptamer sensing systems.
Aptamer based surface enhanced Raman scattering detection of adenosine using various core sizes of Au-Ag core-shell nanoparticles
(2014-01-01)
Ko, Fu-Hsiang
;
Chang, Yu-Cheng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The present study synthesizes different sizes of Au nanoparticles (NPs) by adjusting the concentration of citrate. This method produces Au NPs with uniform sizes that can be used to grow Au-Ag core-shell NPs by the seeding growth method. We report the fabrication of monolayer Au NPs or Au-Ag core-shell NPs through the self-assembly of NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. The results indicate that the self-assembly time of Au NPs or Au-Ag core-shell NPs plays a crucial role in determining the surface coverage of NPs on the silicon substrate. The appropriate sizes of Au NPs or Au-Ag core-shell NPs were optimized to yield the greatest SERS effect in the rhodamine B molecule. The substrates with self-assembled Au-Ag core-shell NPs can also be used to detect adenosine by a structure-switch aptamer. The combination of Au-Ag core-shell NPs and DNA-based adenosine sensors provides a facile, high enhancement, low detection limit (0.1 nM) and low cost fabrication, which shall be of significant value for practical applications of other aptamer sensing systems.
Aqueous Solution-Processable, Flexible Thin-Film Transistors Based on Crosslinked Chitosan Dielectric Thin Films
(2018-03-01)
Singh, Ranjodh
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Lin, Yen-Ting
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Ko, Fu-Hsiang
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材料科學與工程學系
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Department of Materials Science and Engineering
The hydrophilic character of chitosan (CS) limits its use as a gate dielectric material in thin-film transistors (TFTs) based on aqueous solution-processable semiconductor materials. In this study, this drawback is overcome through controlled crosslinking of CS and report, for the first time, its application to aqueous solution-processable TFTs. In comparison to natural CS thin films, crosslinked chitosan (Cr-CS) thin films are hydrophobic. The dielectric properties of Cr-CS thin films are explored through fabrication of metal-insulator-metal devices on a flexible substrate. Compared to natural CS, the Cr-CS dielectric thin films show enhanced environmental and water stabilities, with a high breakdown voltage (10 V) and low leakage current (0.02 nA). The compatibility of Cr-CS dielectric thin films with aqueous solution-processable semiconductors is demonstrated by growing ZnO nanorods via a hydrothermal method to fabricate flexible TFT devices. The ZnO nanorod-based TFTs show a high field-effect mobility (linear regime) of 10.48 cm(2) V-1 s(-1). Low temperature processing conditions (below 100 degrees C) and water as the solvent are utilized to ensure the process is environmental friendly to address the e-waste problem.
Arranging silver nanowire arrays by microcontact printing for solar cells application
(2016-08-20)
Lin, Ching-Chang
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Sun, Wen-Hsien
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Liu, Shuenyu
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Liu, Lai-Yi
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Cheng, Chieh
Atmospheric-pressure microplasma in dielectrophoresis-driven bubbles for optical emission spectroscopy
(2012)
Fan, Shih-Kang
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Shen, Yan-Ting
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Tsai, Ling-Pin
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Hsu, Cheng-Che
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Ko, Fu-Hsiang
"The manipulation of bubbles and the ignition of microplasma within a 200 nL bubble at atmospheric pressure and in an inert silicone oil environment were achieved. Driven by dielectrophoresis (DEP), bubble generation, transportation, mixing, splitting, and expelling were demonstrated. This process facilitated the preparation of various bubbles with tuneable gas compositions. Different gas bubbles, including air, argon (Ar), helium (He), and Ar/He mixtures, were manipulated and ignited to the plasma state by dielectric barrier discharge (DBD) within a 50 mm-high gap between parallel plates. Moving and splitting the atmospheric-pressure microplasma in different gas bubbles were achieved by DEP. The excited light of the microplasma was recorded by an optical spectrometer for the optical emission spectroscopy (OES) analyses. The characteristic peaks of air, Ar, and He were observed in the DEP-driven microplasma. With the capability to manipulate bubbles and microplasma, this platform could be used for gas analyses in the future."
Au-Ag core-shell nanoparticles with controllable shell thicknesses for the detection of adenosine by surface enhanced Raman scattering
(2015-05-01)
Ko, Fu-Hsiang
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Tai, Ming-Rou
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Liu, Fu-Ken
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Chang, Yu-Cheng
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材料科學與工程學系
In this study, we report a feasible aqueous chemical method to synthesize Au core-Ag shell nanoparticles (NPs) by seeding growth approach. The concentration of Au NPs plays an important role in growing the different thicknesses of Ag shells. The design of signaling aptamer utilizes the target-induced switching between an aptamer/DNA duplex and an aptamer/target complex. The surface enhanced Raman scattering (SERS) signal was enhanced upon the hybridization of the Raman reporter-labeled DNA released from the target-induced displacement with the captured DNA immobilized on the silicon substrate with Au-Ag core-shell NPs. This substrate with 12.4 nm Ag shell shows high reproducibility, strong enhancement, and a low detection limit (1 nM). The enhancement in DNA-based adenosine detection properties shall be advantageous in applications for other aptamer sensing systems. (C) 2015 Elsevier B.V. All rights reserved.