Related Experiment Videos
Photoinduced electron storage and surface plasmon modulation in Ag@TiO2 clusters
Tsutomu Hirakawa1, Prashant V Kamat
1Notre Dame Radiation Laboratory and Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556-0579, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|February 8, 2006
Summary
Photoexcitation of silver-titanium dioxide composites enables reversible charging. Electrons injected into the silver core cause a surface plasmon band shift, which is restored upon electron discharge.
Area of Science:
- Materials Science
- Nanotechnology
- Photochemistry
Background:
- Silver-titanium dioxide (Ag@TiO2) core-shell nanoparticles exhibit unique optical and electronic properties.
- Photoinduced charge transfer is a key phenomenon in semiconductor-based nanomaterials.
Purpose of the Study:
- To investigate the reversible charging and discharging effects in Ag@TiO2 composites upon photoexcitation.
- To understand the relationship between electron transfer and surface plasmon resonance shifts.
Main Methods:
- Fabrication of Ag@TiO2 core-shell nanostructures.
- Photoexcitation using UV-Vis spectroscopy to monitor changes in surface plasmon resonance.
- Controlled electron transfer studies using electron acceptors.
Main Results:
- Photoexcitation of the TiO2 shell induced charge separation, leading to electron injection into the silver core.
- Charging of the silver core resulted in a measurable blue shift of the surface plasmon band from 460 nm to 430 nm.
- Discharging of stored electrons upon exposure to an electron acceptor restored the original surface plasmon absorption band of the silver core.
Conclusions:
- Ag@TiO2 composites demonstrate reversible photoinduced charging and discharging capabilities.
- The observed surface plasmon band shift is a direct indicator of electron storage in the silver core.
- This study highlights the potential of Ag@TiO2 nanomaterials for applications involving charge storage and photoresponsive devices.