Comparing the luminescence of ZnS:Mn/CdS:Mn quantum dots

A simple chemical route has been deployed to synthesis highly monodispersed and controllable ZnS and CdS nanoparticles (quantum dots) doped with Mn. XRD investigations shows the cubic structure of both ZnS and CdS nanoparticles and doping has no effect on the structure. The size measurement gives an approximate size of 1.5 nm and 2.5 nm for ZnS: Mn and CdS: Mn quantum dots respectively by Deby-Shreer. UV-Visible is used to study the Optical absorption of ZnS and CdS pure as well as doped nanoparticles. Furthermore as the chemical parameters change, the size of quantum dots change systemically. Of course although doping percentage is a significant parameter in photoluminescence properties of quantum dots, but it has no effect on the size. Photoluminescence spectra obtained at 6% molar of the Mn dopant in CdS: Mn (Ex = 315, Em = 495 nm) and ZnS: Mn (Ex = 285, Em = 572 nm). Microscopic images (SEM, TEM) show the 1-3 nm size for ZnS and CdS nanoparticles.