Facile Liquid-Phase Synthesis of a High-Performance Cd-Doped ZnO-Quantum-Dot-Based Photocatalyst

Doping is an effective functional modification method for improving the optical, electrical, and magnetic properties of semiconductors. Here, Cd-doped wurtzite ZnO-quantum-dot (ZQ) zero-dimensional nanomaterials were successfully prepared via liquid-phase synthesis. The experimental results showed that Cd doping can effectively shorten the bandgap, where the optical bandgap range of Cd-doping photocatalysts were 3.31-3.36 eV; in particular, the Cd5-ZQ (Cd contents of 0.5 wt%) sample reduced the bandgap from 3.39 to 3.31 eV compared to that of pure ZQ . This is consistent with the experimental results, where the simulation calculation results indicated the bandgap reduced from 3.107 to 2.912 eV after introducing Cd. Photoluminescence spectroscopy results confirmed the Cd-ion dopants efficiently capture excited electrons and further prolongs the charge lifetime. The degradation of a methylene blue solution under simulated solar light irradiation revealed that the photocatalytic properties of Cd-ZQ nanomaterial with suitable dopant concentration (Cd content 0.5 wt%) was significantly better than those of pure ZQ. The underlying mechanism involves a synergistic effect, and a reasonable and convenient strategy for uprated performance is presented.

Study on the Third-Order Nonlinear Optical Properties of Cd2+ Ion Doped Zns/PVP Nanocomposite FilmsB. Suresh1, S. Ramachandran1 and G. Shanmugam2

Cd2+ ion doped ZnS/PVP nanocomposite films have been prepared using in-situ chemical method. XRD studies confirm the cubic structure of ZnS for all the films and the nanocrystallite size of ZnS is found to varying from 3.82 to 4.07 nm with Cd doping. The morphology of the films has been analyzed using SEM micrograph which shows the mono dispersion of ZnS nanoparticles in PVP matrix. The interaction between ZnS nanoparticles and PVP polymer matrix has been discussed using FTIR spectra. Optical absorption spectra of the films reveal the blue shift on the absorbance onset with the comparison of bulk ZnS and the estimated optical band gap energy decreases with increasing the concentration of Cd dopant. Photoluminescence spectra show a blue emission peak for all the films. The Z-scan results of three samples show a reverse saturation absorption process in open Z-scan experiment and self-focusing behavior in closed Z-scan experiment. Both ZnS/PVP and Cd2+ ion doped ZnS/PVP films exhibited the large optical nonlinearity and the value of nonlinear refractive index (n2), nonlinear absorption coefficient (β), third-order nonlinear optical susceptibility (χ(3)) and figure of merit (FOM) increase with Cd doping. The estimated n2, β, χ(3) and FOM values were found to be high for 6 mol% Cd doped ZnS/PVP nanocomposite film and they are about 1.771⋅10− 10 m2 W− 1, 4.148⋅10− 3 mW− 1, 1.603⋅10− 4 esu and 9.576⋅10− 6 esu m respectively. The experimental results clearly showed that the Cd2+ ion doped ZnS/PVP nanocomposite film is a worthy candidate for the future nonlinear optical device fabrication.

Surface engineering of linearly fused Au13 units by diphosphine and Cd doping

Large surface‐to‐volume ratio is one of the most intriguing characters of nanoclusters, which endow the surface a critical role in the demonstrating the nanoclusters’ novel properties and applications. In this...

Incorporation of Cd-Doping in SnO2

Tuning the electrical properties of materials by controlling their doping content has been utilized for decades in semiconducting oxides. Here, an atomistic view is successfully employed to obtain local information on the charge distribution and point defects in Cd-doped SnO2. We present a study that uses the time-differential perturbed gamma–gamma angular correlations (TDPAC) method in samples prepared by using a sol–gel approach. The hyperfine field parameters are presented as functions of the annealing temperature in pellet samples to show the evolution of incorporating Cd dopants into the crystal lattice. Additionally, the system was characterized with X-ray fluorescence, electron dispersive spectroscopy, and scanning electron microscopy after the probe nuclei 111In(111Cd) decayed. The TDPAC results reveal that the probe ions were incorporated into two different local environments of the SnO2 lattice at temperatures up to 973 K for cation substitutional sites.