A theoretical approach for the calculation of the bimetallic nanoparticles absorption spectra has been developed as an extension of the Mie theory in which nanoparticles dielectric function is found by the weighted linear combination of the dielectric functions for particles made of the corresponding pure metals. In the frame work of the theoretical model an expression for the resonance light absorption frequency were derived taking in account the interband transitions in the dielectric functions. We proposed a simple method for the on-line monitoring of the bimetallic nanopparticles composition based on the measurementof the absorption pek position. Elaborated theoretical approach was used to investigate the polymer embedded Ag/Au nanoparticles which were prepared by reducing gold and silver salts (HAuCl4 and AgNO3, respectively) by ethylene glycol in presence of poly(vinyl pyrrolidone) (PVP) at room temperature. Calculated absorption spectra of the Ag/Au nanoscopic systems showed good agreement with experimental data. Temporal evolution of the Ag/Au nanoparticles has also been investigated by this approach.
Optical characterization of the polymer embedded alloyed bimetallic nanoparticles
Carotenuto G;
2005
Abstract
A theoretical approach for the calculation of the bimetallic nanoparticles absorption spectra has been developed as an extension of the Mie theory in which nanoparticles dielectric function is found by the weighted linear combination of the dielectric functions for particles made of the corresponding pure metals. In the frame work of the theoretical model an expression for the resonance light absorption frequency were derived taking in account the interband transitions in the dielectric functions. We proposed a simple method for the on-line monitoring of the bimetallic nanopparticles composition based on the measurementof the absorption pek position. Elaborated theoretical approach was used to investigate the polymer embedded Ag/Au nanoparticles which were prepared by reducing gold and silver salts (HAuCl4 and AgNO3, respectively) by ethylene glycol in presence of poly(vinyl pyrrolidone) (PVP) at room temperature. Calculated absorption spectra of the Ag/Au nanoscopic systems showed good agreement with experimental data. Temporal evolution of the Ag/Au nanoparticles has also been investigated by this approach.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
