高ＩＦ論文受理をめざした光ナノテクノロジー研究ネットワーク形成

概要

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We made various attempts to publish high impact factor papers. Here we describe such effortsand research activities carried out in fiscal year 2010. As a research, pulsed laser-inducedmorphological transformation and size-reduction of colloidal gold nanoparticles in the aqueousphase were investigated using transient absorption spectroscopy and transmission electronmicroscopy (TEM). Femtosecond laser-induced fragmentation of gold nanoparticles within 100ps after the laser pulse is interpreted in terms of the Coulomb explosion mechanism. On theother hand, nanosecond laser-induced size-reduction of gold nanoparticles is in good agreementwith the photothermal evaporation mechanism that is based on heating of particles totemperatures above the boiling point of gold (3100 K). Here, the experimentally observedfragmentation thresholds were well-reproduced by simulations based on electron and latticetemperature models and by considering the dissipation of heat into the surrounding medium. Thenumerical method described herein has the advantage of identifying the fragmentationmechanism by considering pulse duration- and energy-dependent thresholds.