Ni-incorporated cadmium sulphide quantum dots for solar cell: An evolution to microstructural and linear-nonlinear optical properties

Abstract

Cadmium sulphide (CdS) compounds have attracted interest due to their applications in opto-electronic devices such as solar cell, sensor, photodiode, etc. The performance of such devices are strongly depends on structure, morphology, and optical properties. Here we report, Ni-incorporated CdS quantum dots(QD) synthesized by conventional chemical co-precipitation method. Ni concentration (0, 2, 4, 6 and 8 wt-%) on Ni-incorporated CdS QD and its microstructural and linear-nonlinear optical properties are extensively investigated. Optical studies derived from UV–ViS. are performed to estimate linear-nonlinear parameters of Ni-incorporated CdS QD by utilizing the absorption and reflection spectra. The optical band gap values decrease from 2.53 to 2.33 eV as Ni content increases. On the other hand, the refractive index values increase with increasing Ni content. Additionally, skin depth, electrical-optical conductivity, and nonlinear parameters are effectively influenced by increasing Ni content in CdS QD.XRD studies confirm that the Ni-incorporated CdS QD exhibits a hexagonal crystal structure with a strong (002) preferential orientation. X-ray peak profile analysis by Scherer method and modified Williamson–Hall method is employed to calculate the crystallite size and lattice parameters such as strain, stress, and energy density of the Ni-incorporated CdS QD. The obtained results indicate that the crystallite size of QD estimated from Scherer and Williamson–Hall methods are correlated and in the range of 2.10–17.89 nm. Energy-dispersive X-ray spectroscopy(EDS) confirms the incorporation of Ni in CdS QD.