Preparation and characterization of a novel system of CdS nanoparticles embedded in borophosphate glass matrix

► Novel systems of CdS nanoparticles embedded in glass matrix were prepared. ► Different sizes of nanoparticles were prepared by changing the annealing conditions. ► Density of the composite systems increases by the doping and size of nanoparticles. ► CdSO4 were detected at the surface of the nanoparticles treated at high temperature. ► Confinement conditions affect the band gap value of the nanoparticles of the same size. A novel composite system of CdS nanoparticles embedded in sodium/potassium/calcium-mixed borophosphate glass has been prepared. The composite was characterized by X-ray diffraction, transmission electron microscope, density measurements, UV–vis absorption and Raman spectroscopies. Different sizes of nanoparticles were prepared by changing the annealing conditions such as temperature and time. Density measurements showed that the density of the composite systems increases by doping and also increases with increasing the size of CdS nanoparticles. X-ray measurements revealed that the structure of the prepared CdS nanoparticles is a hexagonal one and the sizes of the nanoparticles are ranging from 32 to 38Å for the samples annealed at low temperature and short time. However, the sample annealed at high temperature and long time, X-ray and Raman measurements showed a formation of CdSO4 layer at the interface between the surface of the nanoparticles and the host glass matrix. Optical measurements in conjunction with TEM and X-ray proved that the band gaps determined from optical absorption of CdS nanoparticles embedded in the glass matrix are larger than the band gap of the same sizes confined with a high potential barrier. Finally, Raman spectroscopy confirmed the formation of CdS nanoparticles by the appearance of transverse and longitudinal optical phonons of CdS.