Monitoring the photothermal reshaping of individual plasmonic nanorods with coherent mechanical oscillations

BRAGAS, ANDREA V.; GUTIÉRREZ, MARINA V.; DELLA PICCA, FABRICIO; SCARPETTINI, ALBERTO FRANCO

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2018 vol. 122 p. 29598 - 29606

1932-7447

Light absorption in gold nanoparticles leads tothe metal heating that induces photothermal reshaping due to atomic surfacediffusion at temperatures well-below the gold melting point. In this work, weperform time-resolved experiments to measure the frequencies of the extensionalcoherent mechanical mode in single gold nanorods, as a monitor of the changesin their aspect ratio produced by this photoinduced reshape. We show thatphotothermal reshaping is always present in typical pump-probe experimentsconducted in air even at low excitation light irradiances and usually longmeasuring times. Reshaping effect can be reduced by a polymer coating, whichallows faster heat dissipation from the nanoparticle to the environment.