Crystallographic and optical studies on Cr doped ZnS nanocrystals

Abstract

Chromium doped ZnS nanocrystals with pure and 10% compositions were synthesized by chemical co-precipitation route. Samples were characterized by X-ray diffraction (XRD) technique, Fourier transforms infrared spectroscopy (FTIR) and UV-Visible spectrometer. Lattice parameter 'a' decreases and grain size increases with increasing Cr concentration. XRD study shows that both the samples have cubic structure. Grain size increases due to ionic radius. The functional groups and chemical species of Cr doped ZnO samples were determined using FTIR data. UV-Vis study revealed that red shift is clearly observed in absorption band. Surface morphology of pure and 10% Cr doped samples was investigated by SEM technique and it is confirmed that images exibit cubic form of the samples. Using EDS, percentage of chemical compositions of material recorded.

Chromium doped ZnO nanoparticles for energy storage, gas and humidity sensing and spin based electronic devices applications

“…As shown in Fig. 6 Stretching modes of Zn-O-Cr were observed around 833 cm −1 to 908 cm −1 that confirm the presence of defects that resulted from oxygen vacancies which existing in the system due to Cr incorporation in the ZnO lattice (Bodke and Dole 2015). This band confirms that Cr cations have been occupied in the ZnO (NPs) matrix, which matches the XRD results.…”

“…The shoulder band at 612 cm −1 may be assigned to the stretching vibration of Zn-O bonds in octahedral coordinate (Hassan et al 2015a). The increase of Cr +3 doping to ZnO nanoparticles caused the band around 612 cm −1 to shift toward the higher wavenumber 640 cm −1 (in Cr-rich sample), which reveals an increase in the strength of Zn-O bond, that is may attributed to optical phonon confinement by nanostructures, it is highly possible because the nanostructures in our samples are bigger in size than the Bohr exciton radius in ZnO (2.3 nm), this in turn caused the observed increase in its height this is may be due to the stretching vibration of ZnO in the tetrahedral and octahedral coordination respectively may be caused the intensity increase as the Cr content was increased according to the existence of defects states that surrounding to Cr ions (42-43), While, the absorption wide range band 470-570 cm −1 may be due to the stretching vibrational mode of vibrational Zn, and Cr cations (Bodke and Dole 2015;Farag et al 2022).…”

Catalytic Hydrogen Evolution from H2S Cracking over CrxZnS Catalyst in a Cylindrical Single-Layered Dielectric Barrier Discharge Plasma Reactor

“…Cr 0.20 ZnS, Cr 0.25 ZnS and Cr 0.30 ZnS catalysts represented the absorbance values of 0.162 nm, 0.324 nm and 0.563 nm, respectively. Bodke et al [ 14 ] reported that the concentration of doped Cr 3+ had a pronounced effect on the optical properties of the ZnS catalyst and witnessed a significant red-shift in the absorption of Cr-doped ZnS.…”

“…They used different molar ratios of Cr/Zn (x = 0.10, 0.15, 0.20 and 0.25) in their investigations. These molar ratios resulted in 81.8%, 87.4%, 100% and 89.7% conversion of H 2 S, respectively [ 12 , 13 , 14 ].…”

“…Barnhart et al [ 13 ] reported that Cr is the 21st most common element in the Earth’s crust, with a concentration of 100 ppm. Poornaprakash et al [ 14 ] explained that chromium is an important metal that has an abundant shell structure. Moreover, due to the closed ionic radius of Cr 3+ (0.63 Å) and Zn 2+ (0.74 Å), it is easy for Cr 3+ to substitute Zn 2+ and penetrate into the host lattice of ZnS.…”