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Carrier Lifetime Measurements in Semiconductors through the Microwave Photoconductivity Decay Method
Published on: April 18, 2019
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Quantifying Wavelength-Dependent Plasmonic Hot Carrier Energy Distributions at Metal/Semiconductor Interfaces
Yun Yu1, Kanishka D Wijesekara2, Xiaoxing Xi2
1Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States.
ACS Nano
|February 27, 2019
Summary
Plasmonic hot carriers in gold/titanium dioxide nanostructures drive charge-transfer reactions. This study quantifies their energy distribution, revealing insights into photocatalytic device efficiency.
Area of Science:
- Materials Science
- Nanotechnology
- Photochemistry
Background:
- Localized surface plasmons in metal nanostructures generate hot carriers via nonradiative decay, driving surface charge-transfer reactions.
- Metal nanoparticle/semiconductor heterostructures are key in photocatalytic devices due to efficient electron-hole separation.
- Hot carrier energy distribution dictates the redox reaction driving capability of photocatalytic devices.
Purpose of the Study:
- To quantify the thermalized hot carrier energy distribution in gold/titanium dioxide (Au/TiO2) nanostructures.
- To determine the quantum efficiencies and oxidizing power of plasmon-generated hot carriers.
- To gain insight into the energy distribution of hot holes at metal/semiconductor heterostructures.
Main Methods:
- Utilized wavelength-dependent scanning electrochemical microscopy.
- Employed a series of molecular probes with varying redox potentials.
- Analyzed wavelength-dependent reaction rates and photocurrent across the Au/TiO2 interface.
Main Results:
- Quantified the thermalized hot carrier energy distribution in Au/TiO2 nanostructures.
- Determined quantum efficiencies and oxidizing power of hot carriers as a function of wavelength.
- Observed reaction efficiency tracking the surface plasmon resonance spectrum of Au nanoparticles.
Conclusions:
- Plasmon excitation facilitates photocatalytic reactions driven by hot carriers.
- Molecular probe responses elucidate the energy distribution of generated hot holes.
- Results offer crucial insights into hot carrier energies and quantum efficiencies in plasmonic photocatalysis.
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