|Title:||Know Thy Nano Neighbor. Plasmonic versus Electron Charging Effects of Metal Nanoparticles in Dye-Sensitized Solar Cells|
Chen, Wei Ta
Kamat, Prashant V.
Department of Materials Science and Engineering
|Keywords:||semiconductor-metal composite;photocatalysts;TiO2;core-shell nanoparticles;localized surface plasmon;solar energy conversion;electron storage;Fermi level equilibration|
|Abstract:||Neighboring metal nanoparticles influence photovoltaic and photocatalytic behavior of semiconductor nanostructures either through Fermi level equilibration by accepting electrons or inducing localized surface plasmon effects. By employing SiO2- and TiO2-capped Au nanoparticles we have identified the mechanism with which the performance of dye-sensitized solar cells (DSSC) is Influenced by the neighboring metal nanoparticles. The efficiency of an N719 dye-sensitized solar cell (9.3%) increased to 10.2% upon incorporation of 0.7% Au@SiO2 and to 9.8% upon loading of 0.7% Au@TiO2 nanoparticles. The plasmonic effect as monitored by introducing Au@SiO2 in DSSC produces higher photocurrent. However, Au nanoparticles undergo charge equilibration with TiO2 nanoparticles and shift the apparent Fermi level of the composite to more negative potentials. As a result, Au@TiO2 nanoparticle-embedded DSSC exhibit higher photovoltage. A better understanding of these two effects is crucial in exploiting the beneficial aspects of metal nanoparticles in photovoltaics.|
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