Multiphoton Fragmentation of PAMAM G5-Capped Gold Nanoparticles Induced by Picosecond Laser Irradiation at 532 nm

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• 作者：Anna Giusti ; Emilia Giorgetti ; Simona Laza ; Paolo Marsili ; Francesco Giammanco
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：October 18, 2007
• 年：2007
• 卷：111
• 期：41
• 页码：14984 - 14991
• 全文大小：792K
• 年卷期：v.111,no.41(October 18, 2007)
• ISSN：1932-7455

文摘

Fifth-generation ethylendiamine-core poly(amidoamine) (PAMAM G5)-capped gold nanoparticles wereprepared by picosecond laser ablation in water, with the fundamental and second harmonic of a picosecondNd:YAG laser. Although the visible wavelength exhibited a lower ablation threshold than that of the infraredone, the ablation process at 532 nm reached early saturation because of both linear and nonlinear absorptionmechanisms, accompanied by fragmentation of existing nanoparticles. We demonstrate that the onset of thefragmentation can be monitored by simple UV-vis spectroscopy, thanks to the ability of PAMAM G5 tostabilize gold cations, which results in the growth of an intense band at 290 nm. We observed that, whilewith 532 nm (2.33 eV) irradiation a two-photon absorption mechanism induces fragmentation of thenanoparticles, the suspensions remain stable when irradiated with 1064 nm (1.17 eV) up to 60 GW/cm².