Résumé:
The content of this work deal with the preparation method, the effect of dimensional confinement and the influence of the nanoscale size on the optical properties of materials compared to those of bulk phase. CdSe nanoparticles have been prepared by mecanosynthese route then dispersed in PMMA medium to elaborate nanocomposite material CdSe/PMMA in thin film form by spin coating process the sample was characterized by X-ray diffraction, UV-vis optical absorption, and photoluminescence spectroscopy analyses. XRD patterns showed that CdSe nanoparticles have hexagonal unit cell structure. The UV-vis absorption spectrum of these dispersed NCs exhibit excitonic peaks at 2.67eV resulting from the electron-hole coupling transitions, attributed to optical gap energy and corresponding to a blue shift of the band edge equal to 0.93 eV due to nanosized CdSe .From UV-Vis absorption spectrum and by using the effective mass approximation model (EMA) the average particle size can be estimated to be 2.92 nm. Photoluminescence spectrum exhibits three emission peaks one at 538nm corresponding to band gap excitonic emission and another located at 581nm and at 699 nm
