Fluorescence emission spectra of silver and silver/cobalt nanoparticles

Various aqueous solutions of silver and silver/cobalt nanoparticles (ag and ag/co nps) wereobtained, and their fluorescence emission spectra have been studied. first, colloidal ag nps were preparedby an electrochemical method under different time intervals and at different rotation speeds of rotatingelectrode. next, in a reduction method, ag/co coreshell nps were prepared, using ag nps as a core. thecoreshell structure of ag/co nps has been demonstrated by the transmission electron micrograph (tem)and x-ray diffraction (xrd) pattern. the fluorescence emission spectra of ag and ag/co nps, at differentranges of excitation wavelength, were investigated, which revealed two kinds of fluorescence emissionpeak. the shorter emission peak was fixed at about 485 (for ag nps) and 538 nm (for ag/co nps). for bothnps, with an increase in excitation wavelength, the latter emission peak becomes red-shifted. the effect ofduration time and rotation speed of the rotating electrode, in the electrochemical preparation of ag nps,on its fluorescence emission spectra, has also been investigated.