Advanced Ceramics Progress
Volume:8 Issue: 3, Summer 2022

In this study, novel magnetically separable NiFe2O4@ZnO:Ti nanospheres were synthesized using the heterogeneous nucleation of ZnO:Ti (Ti-doped ZnO) nanoparticles on NiFe2O4 polycrystalline nanospheres through the hydrothermal method. Structural and microstructural properties of the synthesized polycrystalline nanospheres were investigated through Fourier-Transform Infrared Spectra (FTIR), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Field Emission Scanning Electron Microscopy (FESEM) using an Energy-Dispersive X-ray (EDX) spectrometer. The effect of calcination on the magnetic and optical properties was also studied. The optical features of the synthesized nanoparticles were recorded using UV-Vis spectroscopy, indicating the absorption peak in the visible region. The band gap energy of pure ZnO, ZnO:Ti, and NiFe2O4@ZnO:Ti before and after calcination was calculated as 3.21 eV, 2.92 eV, 2.44 eV, and 2.04 eV, respectively. Further, Vibrating Sample Magnetometer (VSM) was employed to examine the magnetic features, and the saturation magnetization (Ms) values of NiFe2O4 and NiFe2O4@ZnO:Ti non-calcined and calcined were obtained as 63.6 emu/g, 21.3 emu/g, and 15.3 emu/g, respectively. The findings revealed that calcination of NiFe2O4@ZnO:Ti nanospheres improved the optical properties and reduced the band gap energy. However, NiFe2O4 combination with nonmagnetic matrix and calcination of NiFe2O4@ZnO:Ti nanoparticles decreased the Ms value and response to the external magnetic field.

Novel luminous materials are always required in solid-state light-emitting diodes and displays applications. In this regard, the current study investigated the luminescence properties of cerium-doped zinc oxide/cadmium tungstate (ZnO/CdWO4: Ce) nanocomposite particles under proton, laser, and gamma-ray excitations. The XRD results revealed the simultaneous existence of monoclinic CWO and hexagonal ZnO. Doped nanocomposite particles under proton/laser irradiations displayed significant luminescence in the blue-green region compared with the pure nanocomposite. In addition, Thermo-Luminescence (TL) study of the doped pellet showed a stronger glow peak at 350-400 °C. According to the TEM, the doped nanoparticles had an average diameter of 70-150 nanometers. The existence of Zn, O, Cd, W, and Ce elements in the composites was confirmed by the EDX technique. The obtained results showed that the produced ZnO/CWO: Ce nanocomposite particles could be promising materials to be used in optoelectronic devices.

In this paper, the performance of photodetectors based on CH3NH3PbBr3 organic‐inorganic hybrid was evaluated, given their wide applications in different industries. This structure an appropriate for the active layer of photodetector device. Impressive results are concluded by changing the halogen atom and the energy gap of the hybrid structures. The obtained results reveal that the investigation of the appropriate organic cation and suitable halogen atom, as well as the concentration of the hybrids in the photodetectors, are necessary to find a suitable condition for an effective photodetectors. Exciting results are achieved by considering the Current-voltage (I-V) curves of darkness and light. The I-V curve with 1.8 wt. % concentration of CH3NH3PbBr3 organic‐inorganic hybrid shows the Isc of 1 μA and response of 0.027 μA/W. The device with 1.2 wt. % concentration showed Isc of 0.25 μA and response of 0.006 μA/W. Perovskites are optically configurable so that they acquire proper band gaps with high slope absorption edge and considerable efficiencies in collecting the charges produced by the light.

Hydroxyapatite (HAp, Ca10(PO4)6(OH)2), a calcium phosphate bio ceramic which is chemically similar to natural bone mineral, is widely used as a scaffolding material in bone tissue engineering. In this study, Hydroxyapatite (HAp) ceramics were sintered using microwave in one- and two-step heat treatment. The sintering temperatures in the first heat treatment step were in the range of 965-1000 °C without isothermal holding, and the power levels of the microwave were set at 600, 750, and 900 W. The temperatures in the second heat treatment step were 600, 735, and 860 °C. Of note, HAp-to-Tricalcium phosphate (TCP) phase transformation was not detected at 1000 °C; instead, the preferred growth of (211) planes corresponding to the circular morphology was observed. As observed in the XRD images, crystallite degradation occurred in two-step sintered samples. In addition, the SEM micrographs indicated that the open porosity in the two-step heat treated samples was more than that of samples which were heat treated in one step. In case the sintering temperature was set at 1000 °C, the maximum density values of 92 % and 95 % were obtained for one- and two-step sintered samples, respectively.

In this study, a novel TiO2-CuS heterojunction nanocomposite was prepared from TiO2 anatase nanoparticles and CuS nanoflakes through hydrothermal method and used, for the first time, as a visible-light photocatalyst for decomposition of agricultural insecticide Nitenpyram. Crystallinity, shape, and size of particles, and optical properties of the prepared nanocomposite were investigated using FESEM, XRD, Mott-Schottky, photoluminescence (PL), and UV-Visible spectroscopy analyses. The results indicated that the TiO2-CuS heterojunction nanocomposite was successfully prepared and compared to the pure CuS and TiO2 semiconductors, it exhibited a better photocatalytic performance mainly due to the improvement in optical properties (increasing the ability of visible-light absorbance) and reduction of the photoinduced electron and hole recombination rate. According to the Mott-Schottky analysis and radical scavenger tests, superoxide radical was detected as the major oxidizing agent involved in photocatalytic degradation of Nitenpyram, and a type II charge transfer pathway was suggested to improve the photocatalytic activity.

In this study, Cu and Cu-Co films were prepared using DC Magnetron sputtering system on silicon substrates. Any increase in the roughness and thickness of films would intensify the scattering of the sputtered atoms and consequently, the atoms would lose enough time to find the lowest energy required by each nanoparticle (NP). The height changes on the surface of the scanned films are indicative of the topological phase of the films. According to the results, the films were not smooth that made them undergo a second phase change. The address layer and thickness changes did not have much effect on the degree of isolation. For this reason, the graphs demonstrated close and identical results. All samples display strong light absorption over the entire spectral range, suggesting that they could bide all light-absorber materials. At the peak of approximately 2.7, the cross-point of d(⍺hν)/d(hν) curves yielded optical band gap (Eg) values of 2.68 eV, 2.76 eV, 2.85 eV, and 2.73 eV corresponding to the Samples 1 to 4, respectively. The optical conductivity of the films increased upon increasing the energy. The SEM images confirmed that the obtained cobalt nanocrystals was approximately spherical in shape with an average diameter less than 80 nm.