Optimization of the properties of Mn doped ZnS quantum dots capped with thiourea.

In this work, the impact of various concentrations of dopant ion on the structural and optical properties of manganese doped ZnS Quantum Dots (MnZnS QDs) in presence of a capping agent has been investigated. MnZnS QDs with various concentration of manganese were prepared by chemical precipitation method using thiourea as the capping agent. The prepared Quantum Dots were characterized by various techniques like X-ray diffraction spectroscopy (XRD), UV-vis. spectroscopy, FT-IR spectroscopy, Diffuse reflectance spectroscopy (DRS) and Fluorescence spectroscopy (PL). The results revealed that the size and optical properties of MnZnS QDs varied by dopant ion concentration. FT-IR and PL results confirmed the incorporation of manganese into ZnS crystal structure, and XRD results showed that MnZnS nanoparticles crystallized in a zinc blende structure.PL intensity of thiourea capped MnZnS QDs (TH- MnZnS QDs) were compared, and TH-MnZnS QD-3 (Mn- 1mmol) was found to have the highest PL intensity. The band gap values decrease with increase in concentration of dopant. [ABSTRACT FROM AUTHOR]