Browsing by Author "Chiu, Kuo-Chuang"

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Functionalized Silica Nanoparticles by Nanometallic Ag Decoration for Optical Sensing of Organic Molecule
(2010-09-23)
Jean, Ren-Der
;
Chiu, Kuo-Chuang
;
Chen, Tsung-Han
;
Chen, Chun-Hua
;
Liu, Dean-Mo
Sensing technologies based on metallic nanoparticles, known as Ag, Au, and so on, have raised enormous interest for their extraordinary sensing resolution and sensitivity to analytes of chemical or biological importance under optical detection have received wide attention in recent decades. Currently, a discrete nanoparticle in a free-standing form, either being organically or biologically modified on the nanoparticle surface, on a given substrate surface region has been employed for photosensing purpose. However, metallic nanoparticles suffering from physical and chemical instability such as oxidation, interparticle coupling, agglomeration, and so on during the processing stages may render undesirable outcomes, which further results in poorer performance than the theoretical expectation. Here we propose a facile and elegant concept to prepare an Ag-decorated silica nanoparticle (hereinafter termed core-shell SiO(2)@Ag nanosphere) based on the modified Stober method. The Ag nanoparticles with an average size controlled at about 1, 3, and 5 nm deposited over the surface of the silica nanocarrier were well separated, making the resulting SiO(2)@Ag nanospheres. The nanospheres showed physically and optically stable surface plasmon resonance spectra and also demonstrated a relatively high Ag-sized dependent sensitivity to ppb level for the detection of analyte molecule, that is, melamine. Theoretical model fitting has been well managed to correlate the optical behavior of the nanosensors, and the outcomes strongly indicated a promising potential of the Ag-decorated SiO(2) core-shell nanospheres for sensory applications.
Transparent SiO2-Ag core-satellite nanoparticle assembled layer for plasmonic-based chemical sensors
(2012-05-28)
Chen, Tsung-Han
;
Jean, Ren-Der
;
Chiu, Kuo-Chuang
;
Chen, Chun-Hua
;
Liu, Dean-Mo
We discovered a promising sensing capability of SiO2@Ag core-satellite nanoparticles with respect to organic melamine when they were consolidated into a solid-type thin-film entity. A series of theoretical models were proposed which provided calculation outcomes superior to those of existing models for the localized surface plasmon resonance spectra of the solid-state assemblies. We envisioned not only that such a SiO2@Ag film is a potential candidate for a transparent solid-state optical nanosensor for the detection of organic molecules but also that the resulting plasmonic resonance model facilitates a better understanding of such a solid-state nanosensor used for a number of sensory applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4722583]