Characterization by Optical Extinction Spectroscopy of Ag NPs synthesized by fs laser ablation using different stabilizers

DAVID MUÑETÓN ARBOLEDA; JESICA M. J. SANTILLÁN; VALERIA B. ARCE; LUCÍA B. SCAFFARDI ; DANIEL C. SCHINCA

CABA

Congreso; XVII Giambiagi School 2015, ?International Year of Light and Light based technologies?; 2015

Facultad de Ciencias Exactas y Naturales, UBA

Strong research efforts have been devoted in the last decay to develop synthesis of noble metal nanoparticles (NPs) due to their applications in many areas of science and technologies. Silver NPs show unique chemical, physical and optoelectronic properties [1, 2] with good potential for use in medical therapeutics, high density optical recording. However, the synthesis of stable colloids still remains as a big challenge. In this presentation, we study the characteristics of size stabilization of Ag colloids NPs fabricated by fs laser ablation in water and aqueous solutions using trisodium citrate (Na3C6H5O7) and starch as stabilizing agents at different concentrations. Colloidal suspensions were obtained using a 100 fs amplified Ti:Sa laser system, working at = 800 nm and a repetition frequency of 1 kHz. The laser was focused on a solid silver target immersed in the liquid media at different pulse energies (100 μJ y 500 μJ). The colloids were experimentally characterized through Transmission Electron Microscopy (TEM) and Optical Extinction Spectroscopy (OES). Experimental extinction spectra were fitted using Mie theory [3] considering a suitable size modification of the bulk experimental complex dielectric function and leaving size as the fitting parameter [4, 5]. The stabilizers modify Ag NPs surface through functional group in their chemical structure. This fitting procedure yielded broader size distribution for water, intermediate for starch and narrower for citrate.