Optical Properties of Pure and Alloyed Silver-Copper Nanoparticles Embedded and Coupled in Dielectric Matrixes

摘要

In this study by using the boundary element method, influence of various parameters on the response to electromagnetic radiation for pure and alloyed silver-copper was investigated. The results demonstrate decreasing interparticle gap from 20 nm to 1 nm for silver coupled nanoparticles leads to shifting the wavelength of optical extinction peak from 362 nm to 393 nm. Decreasing interparticle gap from 20 nm to 1 nm for Cu coupled nanoparticles leads to shifting the wavelength of optical extinction peak from 323 nm to 336 nm. By an increase in the medium refractive index of 1 to 2 the peak of optical extinction for a coupled Cu nanoparticles with 1 nm gap distance the wavelength of plasmon resonance peak shifted from 336 nm to 366 nm and longitudinal plasmon resonance peak shifted from 498 nm to 559 nm. By changing the composition of an alloy of copper and silver nanoparticles with diameter of 10 nm in dielectric matrix with refractive index 1.3 the wavelength of plasmon resonance peak shifted from 378 nm for pure silver nanoparticles to 530 nm for pure copper nanoparticles. In addition for Cu-Ag alloy coupled nanoparticles with 1 nm interparticle gap, the wavelength of resonance peak shifted from 420 nm for pure silver nanoparticles to 544 nm for pure copper nanoparticles. In the case of embedded nanoparticles for coupled silver nanoparticles with 6 nm gap distance, the wavelength of resonance peak shifted from 396 nm to 409 nm, and for coupled silver nanoparticles with 2 nm gap distance, the wavelength of resonance peak shifted from 414 nm to 430 nm. Furthermore for coupled Cu nanoparticles with 2 nm gap distance, the wavelength of resonance peak shifted from 575 nm to 582 nm. The results could be employed for plasmatic sensor design and fabrication.