Effect of Dopant Precursor Solutions on the Structural and Optical Properties of ZnS:Cu Nanophosphors

Nanoparticles of ZnS doped with Cu (ZnS:Cu) were prepared at room temperature by wet chemical method without any capping agent using two dopant precursor solutions-aqueous: (i) Copper acetate [ZnS:CA] and (ii) Copper nitrate [ZnS:CN] solutions. The characterization of the samples was carried out for the structural, surface morphological and optical properties. XRD analysis results revealed the formation of cubic structure ZnS:Cu particles with an average size of 2.5 nm. From diffuse reflectance spectral (DRS) studies the band gap was found to be higher than bulk due to quantum confinement effect. In Photoluminescence (PL) spectra a sulphur vacancy related blue emission around 432 nm and a green emission from the recombination between the shallow donor level and the t₂ level of Cu were observed. The ZnS:CN nanoparticles showed enhanced luminescence property compared with that of ZnS:CA nanoparticles.