Influence of transition metals doping (M) on the structural, optical, and electronic properties of non-stoichiometric nano-CdS1-x:Mx

Non-stoichiometric cadmium sulfide, CdS0.9, nanomaterials doped with Mn, Co, Cu, and Zn (CdS0.9M0.1, M = Mn, Co, Cu, Zn) were prepared using a thermolysis procedure. X-ray diffraction analysis revealed that all doped samples have the same CdS structure (hexagonal and cubic) except the Co-doped sample, where some slight cobalt oxides were detected. The influence of different transition metals doping on the structural parameters of the phases developed has been examined by performing Rietveld analysis, also the residing of doped metals at the possible crystallographic sites and the possibility to oxygen ion diffusion into the matrix were also studied. Images from high-resolution transmission electron microscope confirmed the quantum dots nature of the formed samples. The optical bandgap could be tailored and photoluminescence properties of the samples were affected by the different types of doped metals. The doped samples emitted violet, blue, and green colors depending on the type of doped metals. DFT calculation was performed to discuss the possibility of the presence of oxygen ions in doped non-stoichiometric CdS samples. DFT calculations demonstrated that the Cu-doped non-stoichiometric CdS sample has the highest photoconductivity in the infrared range. The modified properties of CdS0.9M0.1 nanomaterials by changing the doped metals make them good candidates for photocatalytic activity and optoelectronics applications.

Automated summary

The non-stoichiometric cadmium sulfide nanomaterials doped with various transition metals showed modified structural parameters and optical properties, with the doped samples emitting violet, blue, and green colors. The presence of doped metals at crystallographic sites and the diffusion of oxygen ions were studied using Rietveld analysis and high-resolution transmission electron microscope imaging. DFT calculations suggested that Cu-doped CdS samples exhibited the highest photoconductivity in the infrared range.