Optical properties of silver, silver sulfide and silver selenide nanoparticles and antibacterial applications

This work presents the optical properties and antibacterial activity of silver nanoparticles (AgNPs) and their semiconductors from S and Se (Ag2S and Ag2Se nanoparticles). The nanoparticles were synthesized and stabilized in the matrix of the synthetic zeolite A4. Both compounds Ag2S and Ag2Se nanoparticles show a size of around 9 nm and quasi-spherical morphology. The interplanar distances calculated in the TEM images confirm the presence of metallic and semiconductor nanoparticles with hexagonal, monoclinic and orthorhombic structures for nanoparticles Ag, Ag2S and Ag2Se, respectively. The Surface plasmon resonance for AgNPs was obtained around 415 nm. Furthermore, in nanoparticles Ag2S and Ag2Se we identified absorptions bands in the visible region with maxima around 330 and 375 nm. The presence of SERS effect caused by metallic nano-particles on the surface of the zeolite was observed. The antibacterial activity of the nanoparticles stabilized in the zeolite was analyzed against gram-negative bacteria and gram-positive bacteria.