Research
| Plasmonics for Surface-Enhanced Spectroscopy and Analysis |
| Noble metallic nanostructures exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the Raman scattering cross sections are dramatically enhanced for the molecules adsorbed thereon. In recent years, it has been reported that even single molecule detection is possible by SERS, suggesting that the enhancement factor can reach as much as 1014-1015; the effective Raman cross-sections are then comparable to the usual fluorescence cross-sections. Since its first observation in the 1970s, SERS has thus been an object of great interest in many areas of science and technology. |
| SERS is currently enjoying a massive renaissance. The level of understanding is so advanced that researchers begin to form strategies for exploiting SERS as a general platform for chemical and biological analysis with unprecedented routine levels of sensitivity, specificity and reproducibility, a result of combining the huge enhancements that SERS-active structures suggested by simulation are capable of exhibiting, together with the inherent molecular spectroscopic nature of Raman. |
| Our research is planned to overcome the obstacles of SERS. Firstly, we strive to enhance our understanding on the fundamental mechanism of SERS by conducting model experiments and theoretical computations. Secondly, we intend to devise a more reliable and cost-effective method to fabricate highly SERS-active nanostructures. Thirdly, we are attempting to increase the application prospects of SERS in chemical analysis, two-dimensional organic patterning, and even antibacterial treatment and biomolecular sensing and recognition. In specific, we are conducting the following theme of work: |
| (1) Investigations to clarify the two important enhancement mechanisms in SERS phenomena – electromagnetic and chemical enhancement mechanisms. |
| “Surface-Enhanced Raman Scattering Characteristics of Nanogaps Formed by A Flat Ag Substrate and Spherical Pt Nanoparticles “, Spec. Chim. Acta Part A, 2013, 100, 10-14. |
| “Surface-Enhanced Raman Scattering of 4,4’-Dimercaptoazobenzene Trapped in Au Nanogaps”, Phys.Chem.Chem.Phys, 2012, 14, 4095-4100. |
| “Characteristics of Nanogaps Formed by Planar Au and Pt Nanoparticles Revealed by Raman Spectroscopy”, J. Phys. Chem. C, 2011, 115, 21047-21055. |
| (2) Development of optically tunable metal nanostructures for ready application of SERS to chemical analysis. |
| “Surface-Enhanced Raman Scattering Characteristics of 4-Nitrobenzenethiol Adsorbed on Palladium and Silver Thin Films “, Vib. Spectrosc., 2014, 70, 120-124. |
| “Enhanced Raman Scattering in Gaps Formed by Planar Au and Au/Ag Alloy Nanoparticles”, J. Phys. Chem. C, 2013, 117, 11421-11427. |
| “A Novel Fabrication of Silver-Coated Glass Capillaries for Ready SERS-Based Detection of Dissolved Chemical Species”, Analytical and Bioanalytical Chemistry, 2010, 397, 557-562. |
| (3) Self-assembly of poly(ethylenimine)-capped Au/Ag nanoparticles at toluene-water interface for efficient surface-enhanced Raman scattering. |
| “Novel Fabrication and Catalytic Application of Poly(ethylenimine)-Stabilized Gold-Silver Alloy Nanoparticles”, J. Nanoparticle Research, 2012, 14, 735-744. |
| “Poly(ethylenimine)-Stabilized Silver Nanoparticles Assembled into 2-Dimensional Arrays at Water-Toluene Interface”, Journal of Colloid & Interface Science, 2010, 345, 103-108. |
| “Self-Assembly of Poly(ethylenimine)-Capped Au Nanoparticles at Toluene-Water Interface for Efficient Surface-Enhanced Raman Scattering”, Langmuir, 2008, 24, p7178-7183. |
| (4) Noble metal nanoparticle film as a platform for detecting charged dye molecules by surface-enhanced Raman scattering and metal-enhanced fluorescence. |
| “Polyethylenimine-Capped Ag Nanoparticle Film as a Platform for Detecting Charged Dye Molecules by Surface-Enhanced Raman Scattering and Metal-Enhanced Fluorescence “, ACS Appl. Mater. Inter, 2012, 4, 5498-5504. |
| “Silver-Coated Dye-Embedded Silica Beads: A Core Material of Dual Tagging Sensors Based on Fluorescence and Raman Scattering”, ACS Applied Materials & Interfaces, 2011, 3, 324-330. |
| “Silver-Coated Silica Beads Applicable as Core materials of Dual Tagging Sensors Operating via SERS and MEF”, ACS Applied Materials & Interfaces, 2009, 1, 2174-2180. |
| (5) Cyanide or isocyanide SERS as a platform for detection of volatile organic compounds and hazardous transition metal ions. |
| “Cyanide SERS as a platform for detection of volatile organic compounds and hazardous transition metal ions”, Analyst, 2013, 138, 2988-2994. |
| “Effect of Organic Vapors on Au, Ag, and Au-Ag Alloy Nanoparticle Films with Adsorbed 2,6-Dimethylphenyl Isocyanide “, J. Colloid Interface Sci, 2013, 411, 194-197. |
| “Organic Isocyanide-Adsorbed Gold Nanostructure: A SERS Sensory Device for Indirect Peak-Shift Detection of Volatile Organic Compounds”, Analyst, 2012, 137, 1930-1936. |
| (6) The development of sensitive surface analysis techniques based on SERS. |
| “Fe3+ to Fe2+ Conversion by Plasmonically Generated Hot Electrons from Ag Nanoparticles: Surface-Enhanced Raman Scattering Evidence”, J. Phys. Chem. C, 2014, 118, 3359-3365. |
| “Selective detection of aqueous nitrite ions by surface-enhanced Raman scattering of 4-aminobenzenethiol on Au”, Analyst, 2012, 137, 3836-3840. |
| “The pH Effect on Surface Potential of Polyelectrolytes-Capped Gold Nanoparticles Probed by Surface-Enhanced Raman Scattering, Langmuir, 2010, 26, 19163-19169. |
| (7) Noble fabrication and catalytic application of metal nanostructures. |
| “Poly(ethylenimine)-Stabilized Hollow Gold-Silver Bimetallic Nanoparticles: Fabrication and Catalytic Application”, Bull. Kor. Chem. Soc., 2012, 33, 906-910. |
| “Novel Fabrication and Catalytic Application of Poly(ethylenimine)-Stabilized Gold-Silver Alloy Nanoparticles”, J. Nanoparticle Research, 2012, 14, 735-744. |
| “Facile Synthesis of Silver-Deposited Silanized Magnetite Nanoparticles and Their Application for Catalytic Reduction of Nitrophenols”, Applied Catalysis A: General, 2012, 413-414, 170-175. |