Ion-Specific Effects on Laser Ablation of Silver in Aqueous Electrolyte Solutions

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• 作者：K. ikov&aacute ; B. Vlkov&aacute ; P. Y. Turpin ; C. Fayet
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：March 27, 2008
• 年：2008
• 卷：112
• 期：12
• 页码：4435 - 4443
• 全文大小：495K
• 年卷期：v.112,no.12(March 27, 2008)
• ISSN：1932-7455

文摘

Silver nanoparticle hydrosol formation by laser ablation (LA) of a Ag target immersed in pure water and inaqueous electrolyte solutions (HCl, NaCl, NaOH, AgNO₃, and/or Na₂S₂O₃) of various concentrations hasbeen followed by surface plasmon extinction (SPE) spectral measurements and, for selected samples, bytransmission electron microscopy (TEM), scanning electron microscopy (SEM) imaging, and energy dispersiveX-ray (EDX) analysis. The laser ablation process accompanied by the Ag nanoparticle fragmentation (NF)has been performed with nanosecond laser pulses, by employing either a continuous or an intermittent irradiationregime. SPE spectra have been recorded either after each irradiation step of the stepwise procedure or at theend of the continuous one and, additionally, during a subsequent aging of Ag hydrosols. The presence ofHCl, NaCl, and/or NaOH during LA/NF has led to the stabilization of the resulting Ag nanoparticles, whilethe presence of AgNO₃ and Na₂S₂O₃ has shown a destabilizing effect. The alternations of light and darkperiods in LA/NF process, along with the presence of electrolytes (having different affinities toward Agnanoparticle surfaces and toward Ag⁺ ions as well) can be considered as a new physicochemical parameteraffecting the outcome of LA/NF. Moreover, the light/dark alternations are useful for separating the effects ofions on Ag nanoparticle hydrosols directly under irradiation from those occurring during further aging. Aghydrosols prepared by LA/NF in 1 × 10^-3 M NaCl and aged for 1-2 days have been shown to be excellentsubstrates for surface-enhanced Raman scattering (SERS) measurements owing to the presence of compactaggregates with numerous interstices between nanoparticles and of reduced Ag(0) adsorption sites on chloride-modified Ag nanoparticle surfaces.