Studies on pure and Zn and Mn doped nanocrystalline CdS prepared by thermal decomposition using single source molecular precursors

Abstract

Semiconductors with reduced dimension present a large variety of new interesting properties in comparison to the bulk material and open new ways in the engineering of semiconductors. The electronic and optical properties of II-VI group semiconductor nanoparticles have been extensively investigated in view of a wide variety of applications. Among the semiconductors, CdS is one of the most important wide band gap semiconductors, which has been extensively studied due to its ability to tune emission in the visible region simply by changing its size or shape. Cadmium pyrrolidine dithiocarbamate (Cd(pdtc)2) is one of the interesting metal complexes for the single source precursor synthesis of CdS by thermal decomposition at 150 °C in the presence of HDA which acts as solvent as well as capping agent. Two different morphologies such as spherical and rod shaped nanostructures were obtained with microwave and conventional heating process respectively. HRTEM results show the formation spherical and rod shaped nanoparticles in different heating processes. The calculated values of - ln (Ct/C0) (degradation rate) are approximately linear with the irradiation time t. Hence, the photocatalytic degradation reactions of rhodamine B are following the first-order kinetics. The apparent rate constants were obtained from the relation Kt = ln (C0/Ct) for all nanoparticles using the slope of ln (C0/Ct) versus degradation time graph. The Zn doped CdS nanoparticles enhance the overall degradation rate with respect to the pure and Mn doped CdS nanoparticles. The effect of dopant concentration on the degradation of the dye is also observed for the case of Zn and Mn doped CdS systems. The apparent rate constant value K is calculated for all samples, which increase with increasing the concentration of Mn and Zn. newline newline newline