Cobalt-substituted ZnS QDs: a diluted magnetic semiconductor and efficient photocatalyst

Abstract

A detailed experimental and theoretical investigation has been conducted to understand the microstructural, magnetic, optical, and dielectric properties of Co doped ZnS QDs prepared via chemical co-precipitation techniques.

Sm Doped Cu–Ni Spinel Ferrite Nanoparticles for Hyperthermia and Photocatalytic Applications

“…In the logarithmic scale, the graph will have a straight line and the value of the exponent will be determined by the slope. The exponent values calculated for each sample varied from 0.51 to 0.72, (see the inset of Figure a) indicating that electron hopping occurs at room temperature which could be the process underlying charge conduction. − …”

“…Normally, grain boundaries are seen to be as defects in the lattice . The Cole–Cole plot is the most commonly used technique to isolate the contributions of grains and grain boundaries to the total electrical conductivity of a dielectric nanomaterial. , Here, we use real and imaginary components of the overall dielectric constant to get the dielectric modulus, and then these real and imaginary parts of the modulus are used to derive the Cole–Cole plot as follows: ,− M ′ false( ω false) = ε ′ false( ω false) ε ′ false( ω false) 2 + ε ″ false( ω false) 2 M ″ false( ω false) = ε ″ false( ω false) ε ′ false( ω false) 2 + ε ″ false( ω false) 2 …”

“…The maximum energy was transferred when the frequency of the applied ac field and the electron hopping frequency were equal. 31,35 These as-synthesized ferrite nanomaterials can be used in the domain of microwave devices, as they all showed insignificant dielectric loss near the MHz region.…”

“…This clearly suggested that the nonconductive grain boundaries contributed to the total conductivity more effectively than those of conductive grains. 7,35 With the increase of Sm dopants in Cu−Ni nanoferrites, the radius of the semicircles was found to enhance slightly, which referred to the decrement of dc conductivity in the doped samples.…”

“…A typical type IV adsorption isotherm matches the isotherms recorded for the synthesized samples, indicating the existence of a mesoporous kind of structure. 16,24,35 With the increase of Sm ions in Cu−Ni ferrite nanoparticles, the average particle size reduced systematically which leads to an increment in the nanocatalyst's surface area, improving the dispersion in aqueous solutions as well as increasing the photocatalytic activity. As the mean size decreases with increasing Sm doping, the surface area of the ferrite nanoparticles enhances, which is consistent with the XRD findings.…”