Tracking Energy Relaxation Within Plasmonic Metal Oxide Nanocrystals
Technical Report,01 Sep 2015,31 Aug 2016
University of Texas at Austin Austin United States
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In this report, we have used transient absorption spectroscopy to examine how photoexcitation modifies the optical properties of two metal oxide systems, Sn-doped indium oxide ITO NCs and oxygen-vacancy doped tungsten oxide WO3-x NCs. Plasmonic excitation of either material generates hot electrons on a sub-picosecond timescale that later cool by releasing their energy to lattice phonons. Both of these processes alter the center frequency and line width of a NCs plasmon resonance, but the magnitude of these changes depend on the NCs size, crystallographic structure, and the spatial location of dopants within it. We have also investigated how bandgap photoexcitation can be used to manipulate the plasmon resonance ofWO3-x NCs. Adding additional charge carriers into the conduction band of these NCs induces a hypsochromic shift of their plasmon resonance that dissipates on picosecond timescales once the exciting field is removed, making these materials interesting candidates for fast photoswitches and photonic gates.
- Physical Chemistry
- Solid State Physics