Browsing by Author "Cheng, Chieh"

Now showing 1 - 11 of 11

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.
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%.
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
Design of Artificial Hollow Moth-Eye Structures Using Anodic Nanocones for High-Performance Optics
(2010-12-28)
Wu, Chia-Tien
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Lin, Chun-Hung
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Cheng, Chieh
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Wu, Chung-Shu
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Ting, Huai-Chen
We demonstrated an innovative approach for the fabrication of self-organized, hollow-to-solid nanocone arrays, using a decoupling two-step anodization of an Al/Ta interlayer on a substrate. The porosity of the hollow nanostructures was tunable by the deposited thickness of Ta film. We also employed subwavelength nanocone arrays as Moth-eye structures for high-performance antireflection coatings. These oxide nanostructures greatly suppressed reflectance over a large range of wavelengths and angles of incidence and displayed a good mechanical stability. When a corresponding porosity was designed, these nanostructures could be applied to various substrates for an effective antireflection coating. In addition, we were able to customize antireflection coatings for various types of substrates or materials of interest based on the suitable coating of initial Ta thickness.
Facile synthesis of a biocompatible silver nanoparticle derived tripeptide supramolecular hydrogel for antibacterial wound dressings
(2016)
Simon, Turibius
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Wu, Chung-Shu
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Liang, Jie-Chuan
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Cheng, Chieh
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Ko, Fu-Hsiang
Realizing the widespread demand for biocompatible supramolecular hydrogel based wound dressings, we have developed an N-terminally 2(naphthalen-6-yl) acetic acid (Nap) protected Phe-Phe-Cys peptide (Nap-FFC) using a liquid phase method. This Nap-FFC peptide was used to design a supramolecular hydrogel via a self-assembling process. The Nap-FFC short peptides produced stable and transparent silver nanoparticle-based hydrogels (AgNPs@Nap-FFC) wherein the self-assembled Nap-FFC nanofibers acted as scaffolds for the mineralization of silver nanoparticles (AgNPs) and stabilizers of the synthesized AgNPs. The resultant AgNPs@Nap-FFC nanocomposites were characterized using ultraviolet-visible spectrophotometry (UV-vis spectroscopy), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) studies. The AgNPs@Nap-FFC nanocomposites showed excellent monodispersity, long term stability, and functional flexibility in comparison to other AgNP based nanocomposites. Furthermore, AgNPs@Nap-FFC exhibited strong inhibition against both Gram-positive (methicillin-resistant Staphylococcus aureus) and Gram-negative (Acinetobacter baumannii) bacteria and, most importantly, they showed favorable biocompatibility towards human cervical carcinoma cells (HeLa cells). Hence, this study implies that AgNPs@Nap-FFC nanocomposites can easily be prepared in a cost-effective manner and can be used effectively for future antibacterial wound dressings.
Flexible and miniaturized msm biomolecular photodetector for hydrogen peroxide sensing via chemiluminescence
(2016-08-20)
Lin, Ching-Chang
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Liu, Lai-Yi
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Sun, Wen-Hsien
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Liu, Shuenyu
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Cheng, Chieh
Gold nanorods self-assembly by dielectrophoretic and applications in solar cells
(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
New Synthesis Route of Hydrogel through A Bioinspired Supramolecular Approach: Gelation, Binding Interaction, and in Vitro Dressing
(2015-09-02)
Cheng, Chieh
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Tang, Meng-Che
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Wu, Chung-Shu
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Simon, Turibius
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Ko, Fu-Hsiang
Peptide-based supramolecular hydrogels have been comprehensively investigated in biomaterial applications because of their unique bioactivity, biofunctionality, and biocompatible features. However, the presence of organic building blocks in peptide-based hydrogels often results in low mechanical stability. To expand their practical use and range of applications, it is necessary to develop the tool kit available to prepare bioinspired, peptide-based supramolecular hydrogels with improved mechanical stability. In this paper, we present an innovative electrostatic and cross-linking approach in which naphthyl-Phe-Phe-Cys (NapFFC) oligopeptides are combined with gold nanoparticles (AuNPs) and calcium ions (Ca2+) to produce peptide-based supramolecular hydrogels. We further investigate the interactions among NapFFC, AuNPs and Ca" by microscopy. The morphology of the nanofibrous network constructions and the binding forces exhibited from the hydrogel demonstrated that the combination of two mechanisms successfully enhanced the mechanical stability through the formation of a densely entangled fibrous network of peptide multimers that is attributed to the AuNP linkage and Ca2+-induced agglomeration. UV vis spectrophotometry and fluorescence analysis were also used to demonstrate the enhanced stability of the hydrogel under various conditions such as thermal, solvent erosion, pH value and sonication. All results indicate that the presence of AuNPs and Ca2+ can strengthen the prepared hydrogel by more than doubling the diameter of NapFFC nanofibers, enabling the formation of stronger frameworks and slowing the release of components. Further experiments confirmed that HeLa cells can grow on the bioinspired NapFFC-AuNP hydrogel and exhibit high cell viability and that these cells were killed on contact with a hydrogel containing a drug. Our peptide-based supramolecular hydrogels prepared from the observed electrostatic and cross-linking mechanisn exhibited a significantly improved mechanical stability, making them well suited to use as a drug carrier in hydrogel dressings and as extracellular materials (ECMs) for tissue engineering.
Ultrathin flexible silicon photodetector with silver nanowires plasmonic structure for chemiluminescence sensing
(2016-08-20)
Liu, Lai-Yi
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Lin, Ching-Chnag
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Liu, Shuenyu
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Sun, Wen-Hsien
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Cheng, Chieh
Ultrathin single-crystalline silicon solar cells for mechanically flexible and optimal surface morphology designs
(2015-09-01)
Lin, Ching-Chang
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Chuang, Yi-Jiun
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Sun, Wen-Hsien
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Cheng, Chieh
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Chen, Yu-Tzu
Recently, the evolution of photovoltaic cells in together with flexible electronics rapidly grows up so as to satisfy the flexibility and elasticity needs. Therefore, it will be a breakthrough impact if it is able to develop flexible single-crystalline photovoltaic cells which are fabricated with traditional procedure and provide highly electrical properties as well. This study aims to fabricate the flexible solar photovoltaic device with practical and reproducible method. Generally, the flexible solar photovoltaic is manufactured on the 30 gm-thickness single-crystalline silicon chip by chemical etching process. Versatile design on the flexible device can enhance light trapping effect. The surface texturization and antireflection layer deposition successfully minimize the reflectivity losses from the incident light. In addition, the developed devices under concave bending morphology demonstrates better operating performance than convex and flat configurations. As to the concave bending type, the significant improvement of power conversion efficiency (129% better than flat type, and 161% better than convex type) is observed from a large device current, which is related to the contribution of light trapping enhancement. In combination of all optimal conditions, the flexible device exhibits conversion efficiency up to 13.8%. The development of novel flexible solar photovoltaics with the excellent mechanical flexibility, low silicon material consumption and low fabrication cost demonstrates the potential capability for future solar cells. (C) 2015 Elsevier B.V. All rights reserved.