Time-resolved Photoluminescence Upconversion Microscopy to Probe Hot Electron Dynamics in Plasmonic Nanostructures
Abstract
Noble metal nanoparticles are efficient light absorbers due to the surface plasmon resonance. Itsdecay can generate high energy charge carriers. These hot electrons and holes have the potentialto play an important role in light-assisted catalytic reactions. Understanding the energydistribution and lifetime of these hot carriers is essential for the rational design of efficientplasmonic photocatalysts. However, very little is known about the hot carrier lifetime and theirenergy distribution especially with reactants adsorbed on the surface of the plasmonicnanoparticles. A few theoretical studies exists but have not been tested experimentally, which isdesperately needed and limiting current progress. It has been proposed that the one-photonluminescence in plasmonic nanoparticles involves emission through the high local density ofoptical states provided by the surface plasmon resonance following initial generation of hotelectrons and holes. Probing the photoluminescence lifetime of plasmonic nanoparticlestherefore has the potential to not only validate this mechanism but also yield the hot carrierlifetime and energy distribution. Due to fast electron-phonon relaxation in metals, thephotoluminescence lifetime is expected to be on the order of a few picoseconds. Therefore anultrafast laser is required to temporally resolve the photoluminescence and hence the chargecarrier lifetimes. This proposal request funds to integrate an ultrafast laser into a single particlemicroscope in order to measure the photoluminescence of plasmonic nanostructures via anonlinear upconversion process. The data acquired with this novel instrument promises to yieldunprecedented insight into the relaxation dynamics of excited charge carriers in plasmonicnanostructures.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 19, 2018
- Source ID
- FA95501810575
Entities
People
- Stephan Link
Organizations
- Air Force Office of Scientific Research
- Rice University
- United States Air Force