"Optical spectroscopy extinction method for sizing noble metal nanoparticles generated by femtosecond laser ablation of solid in liquids"

SCHINCA, DANIEL CARLOS; SCAFFARDI, LUCÍA BEATRÍZ; TORCHIA, GUSTAVO ADRIÁN; VIDELA, FABIÁN ALFREDO; SANTILLÁN, JESICA MARÍA JOSÉ; MORENO, PABLO; ROSO, LUIS

Salamanca

Conferencia; 10th EUROPEAN CONFERENCE ON ATOMS, MOLECULES AND PHOTONS; 2010

Universidad de Salamanca

In the last years, there has been an increasing interest in the generation of nanostructures using different methods. Concurrently, there is a constant need for sizing techniques at the nanoscale. Most frequently, the standard method is based on transmission electron microscopy (TEM). Although resolution can be good enough, sample preparation is cumbersome and statistics may be poor. Optical methods arise as an alternative to TEM with competitive resolution and easiness of sample handling. These methods rely basically on absorption or transmission measurements [1,2]. In this work we present results of sizing small silver and gold colloidal nanoparticles generated by fs laser ablation in water and ethanol by fitting their optical extinction spectra. This fitting is based on the electrostatic approximation of Mie theory for particles much smaller than the incident wavelength. We show that, for the case of silver nanoparticles, the presence of a silver oxide shell around the silver bare core affects certain characteristics of the extinction spectrum, such as resonance wavelength, FWHM and contrast, which can be used for sizing purposes. Optical extinction spectra of nanoparticles generated with different fluences are used as fitting examples which show good agreement with TEM distribution measurements. These relations may also be the base for the development of a parametric method that can be readily applied to single particle spectroscopy sizing. <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> [1] G. A. Torchia, L. B. Scaffardi, Cruz Méndez, Pablo Moreno, J. O. Tocho and Luis Roso, Applied Physics A: Material Science & Processing, 93, pp. 967-9, 2008                                      [2]  D. C. Schinca, L. B. Scaffardi, F. A. Videla, G. A. Torchia, P. Moreno and L. Roso,J. Phys. D: Appl. Phys. 42, pp 215102-11,2009