Mechanical Engineering Seminar by Dr. Wei-Shun Chang
When: Friday,
October 27, 2023
2:00 PM
-
3:00 PM
Where: > See description for location
Description: Mechanical Engineering (MNE) SEMINAR
DATE:
Friday, October 27, 2023
TIME:
2:00 p.m. - 3:00 p.m.
LOCATION:
Liberal Arts (LARTS) Room 374
and
ZOOM: https://umassd.zoom.us/j/91640406955?pwd=eklBZWVDOXVDa2VwUFMra1kwNWhjdz09 (Contact hling1@umassd.edu or scunha@umassd.edu for Passcode)
SPEAKER:
Dr. Wei-Shun Chang, Assistant Professor Chemistry & Biochemistry, University of Massachusetts Dartmouth
TOPIC:
Single-Particle Spectroscopy on Plasmonic Photocatalysis
ABSTRACT:
Gold nanoparticles possess unique optical properties as a result of surface plasmon resonances. Plasmonic nanostructures have been explored for various applications, including photocatalysis, nanoscale sensing, photovoltaic devices, bioimaging, and therapeutics. Photoexcitation of surface plasmon resonances generates high-energy carriers or thermal energy that drive chemical reactions. The efficiency of hot carrier and heat generation are regulated by the morphologies of the plasmonic structures. However, the size and shape heterogeneities always appear in the chemically synthesized nanoparticles and impede the detailed structure-function relationship of the nanostructures when characterized by the conventional ensemble measurements. Single-nanoparticle spectroscopy resolves the obstacles of sample heterogeneity to obtain more information that is inaccessible by the ensemble measurements. In this talk, I will present the technique developed in my lab to explore plasmonic photocatalysis at the single-particle level. Measuring the scattering spectra of single nanoparticles provides information about electron transfer at the nanoparticle-substrate interface and the redox reaction on nanoparticles. We have observed efficient electron transfer between gold nanorods and carbon thin films to potentially promote plasmonic catalysis. The capping ligand, polyvinylpyrrolidone, of gold nanorods induces charge separation at the gold-polyvinylpyrrolidone interface and enhances Au+3 reduction for thirteen times under photoexcitation. A detailed mechanism for ligand-induced plasmonic photocatalysis will be discussed. These results provide insight into the design of plasmonic photocatalysts.
BIO:
Wei-Shun Chang is an Assistant Professor in the Department of Chemistry and Biochemistry at UMass Dartmouth. He received B.S. and M.S. from National Taiwan University in 1996 and 1998, respectively. After working in the semiconductor industry, he worked with Prof. Paul Barbara at UT Austin and earned Ph.D. in 2007. Then, he joined Prof. Stephan Link group at Rice University as a postdoctoral researcher and was promoted to research fellow in 2012. He started his independent career at UMass Dartmouth in 2018. His research interest is to study photocatalysis and optical sensing of plasmonic nanomaterials using single-particle spectroscopy and single-molecule imaging. He co-authored 84 peer-reviewed papers with ~ 10,000 citations and received funding from ACS Petroleum Research Fund, the National Science Foundation, and the Office of Noval Research to support his research.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE (BS and MS) are encouraged to attend.
All EAS students are encouraged to attend.
DATE:
Friday, October 27, 2023
TIME:
2:00 p.m. - 3:00 p.m.
LOCATION:
Liberal Arts (LARTS) Room 374
and
ZOOM: https://umassd.zoom.us/j/91640406955?pwd=eklBZWVDOXVDa2VwUFMra1kwNWhjdz09 (Contact hling1@umassd.edu or scunha@umassd.edu for Passcode)
SPEAKER:
Dr. Wei-Shun Chang, Assistant Professor Chemistry & Biochemistry, University of Massachusetts Dartmouth
TOPIC:
Single-Particle Spectroscopy on Plasmonic Photocatalysis
ABSTRACT:
Gold nanoparticles possess unique optical properties as a result of surface plasmon resonances. Plasmonic nanostructures have been explored for various applications, including photocatalysis, nanoscale sensing, photovoltaic devices, bioimaging, and therapeutics. Photoexcitation of surface plasmon resonances generates high-energy carriers or thermal energy that drive chemical reactions. The efficiency of hot carrier and heat generation are regulated by the morphologies of the plasmonic structures. However, the size and shape heterogeneities always appear in the chemically synthesized nanoparticles and impede the detailed structure-function relationship of the nanostructures when characterized by the conventional ensemble measurements. Single-nanoparticle spectroscopy resolves the obstacles of sample heterogeneity to obtain more information that is inaccessible by the ensemble measurements. In this talk, I will present the technique developed in my lab to explore plasmonic photocatalysis at the single-particle level. Measuring the scattering spectra of single nanoparticles provides information about electron transfer at the nanoparticle-substrate interface and the redox reaction on nanoparticles. We have observed efficient electron transfer between gold nanorods and carbon thin films to potentially promote plasmonic catalysis. The capping ligand, polyvinylpyrrolidone, of gold nanorods induces charge separation at the gold-polyvinylpyrrolidone interface and enhances Au+3 reduction for thirteen times under photoexcitation. A detailed mechanism for ligand-induced plasmonic photocatalysis will be discussed. These results provide insight into the design of plasmonic photocatalysts.
BIO:
Wei-Shun Chang is an Assistant Professor in the Department of Chemistry and Biochemistry at UMass Dartmouth. He received B.S. and M.S. from National Taiwan University in 1996 and 1998, respectively. After working in the semiconductor industry, he worked with Prof. Paul Barbara at UT Austin and earned Ph.D. in 2007. Then, he joined Prof. Stephan Link group at Rice University as a postdoctoral researcher and was promoted to research fellow in 2012. He started his independent career at UMass Dartmouth in 2018. His research interest is to study photocatalysis and optical sensing of plasmonic nanomaterials using single-particle spectroscopy and single-molecule imaging. He co-authored 84 peer-reviewed papers with ~ 10,000 citations and received funding from ACS Petroleum Research Fund, the National Science Foundation, and the Office of Noval Research to support his research.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE (BS and MS) are encouraged to attend.
All EAS students are encouraged to attend.
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