Thermally driven structural phase transformation and dislocation density of CdS nanoparticles precipitated without surfactant in KOH alkaline medium

Abstract

The present research demonstrates a detailed discussion for the effect of annealing temperature on the structural transformation and surface morphology of the CdS nanoparticles synthesized using the precipitation method without surfactant in KOH alkaline medium. The annealing temperature used was in the range of 160 – 480 oC. The samples structural, functional group and morphological properties were investigated by using XRD, FTIR and SEM techniques. XRD analysis reveals that the CdS has gradually been transformed from the pure cubic to hexagonal polycrystalline structure as well as improved crystallinity upon increasing the temperature. Besides, the parameters of average crystallite size and dislocation density were calculated using the established Debye- Scherrer equation. The average crystallite size was in nano-dimension and increases gradually with temperature. The FTIR spectra indicate that the characteristic vibration band of CdS emerged in the lower wavenumber region of 650 and 500 cm-1, and the band becomes stronger as the temperature rises. Also, the SEM images demonstrate that the CdS exhibits uniform spherical morphology and the particle size grows larger at elevated temperatures. The improved crystallinity and structural properties tuning ability against temperature allows beneficial optical applications as solar cells, photocatalysts, non-linear optics, light emitting diodes and optoelectronic devices.

Utilizing Gold Nanoparticle Decoration for Enhanced UV Photodetection in CdS Thin Films Fabricated by Pulsed Laser Deposition: Exploiting Plasmon-Induced Effects

“…The diffraction peaks identified at 2θ = 24.91°, 26.65°, 28.29°, 36.70°, 43.77°, and 62.73° angles correspond to the (100), (002), (101), (102), (110), and (104) planes, respectively, indicating a hexagonal phase structure of the thin films. Among these, the (102) and (110) orientations exhibit higher peak intensities, suggesting a preferred directional growth of particles along these planes due to their lower surface energy, a phenomenon that is in agreement with the existing literature [ 48 , 49 , 50 , 51 , 52 ]. This preferred orientation is attributed to the stacking sequence of close-packed Cd planes, with S atoms occupying tetrahedral interstitial sites, emphasizing the significance of these dominant orientations in the crystal growth process [ 53 ].…”

pH-induced wurtzite-zinc blende heterogeneous phase formation, optical properties tuning and thermal stability improvement of green synthesized CdS nanoparticles

“…The observed diffraction peak broadening indicates the reduction of crystallinity and crystallite size [ 15 ]. For further clarification, the average crystallite size was subsequently computed by applying Scherrer’s expression: D = 0.9 λ/β cos θ [ 7 , 9 , 37 ], where D represents the crystallite size, β is the FWHM of the peak in radians, θ denotes the related Bragg diffraction angle and λ designates the X-ray wavelength in nm. Afterwards, the mean crystallite size is ascertained to be 3.99 nm, 3.79 nm, and 3.44 nm at pH values of 12.90, 11.28, and 10.00, respectively, which further elucidates a decrease in crystallite size as the pH value reduces.…”