Quantum confinement effect in heat treated silver oxide nanoparticles

${\mathrm{Ag}}_{\mathrm{2}}\mathrm{O}$ particles of sizes varying from 6.0 to 16 nm have been prepared by a chemical method. These have been subjected to a heat treatment at temperatures varying from 533 to 623 K. The optical absorption spectra of the heat treated particles dispersed on a glass substrate have been delineated. The absorption peak shows a maximum in wavelength as a function of heat treatment temperature. This has been explained on the basis of formation of nanometer-sized silver layer on the ${\mathrm{Ag}}_{\mathrm{2}}\mathrm{O}$ particles and the consequential electron confinement within the same.