Browsing by Author "Searles, Emily Kay"

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    Resonance Energy Transfer and Charge Density Tuning at Plasmonic Interfaces
    (2023-04-12) Searles, Emily Kay; Landes, Christy F
    When photoexcited, plasmons decay through multiple pathways including surface scattering and photoluminescence. Spectroscopic investigation at the single-particle level can provide insight to decay dynamics. The plasmon’s spectral response is sensitive to changes in dielectric environment, charge density, and the chemical interface which can be tuned in-situ. In this thesis, plasmonic-polymeric hybrids are used to increase the electron-hole pair lifetime through interfacial redistribution. Single-particle spectroscopy is used to characterize the energy transfer efficiencies of the hybrid structures by recording changes to the homogenous plasmon linewidth upon acceptor polymerization and dynamic pH tuning. Specifically, non-radiative energy transfer efficiencies > 45% are achieved for Au nanorod-metallated phthalocyanine hybrids while dynamic tuning of resonance energy transfer is achieved in Au nanorod-polyaniline hybrids. We complement results from single-particle scattering and photoluminescence measurements of resonance energy transfer in nanohybrids with the comparison of plasmon modulation at applied potentials. While changes in dark-field scattering during electrochemical charging are well understood, changes to the photoluminescence of plasmonic nanoparticles under similar conditions are less studied and may offer a tool to monitor chemical transformation at hybrid interfaces. We find that changes in the emission of a single gold nanorod during charge density tuning of intraband photoluminescence can be attributed to changes in the Purcell factor and absorption cross-section. While the modulation of interband photoluminescence provides an additional constructive observable, giving promise for establishing dual channel sensing in spectroelectrochemical measurements. The understanding of resonance energy transfer and charge density tuning at the plasmon interface will lead to control and tunability of plasmonic enhancement in ensemble nanocomposites.