The red shift and the broadening of the Raman signal from microcrystalline silicon films is described in terms of a relaxation in the q-vector selection rule for the excitation of the Raman active optical phonons. The relationship between width and shift calculated from the known dispersion relation in c-Si is in good agreement with available data. An increase in the decay rate of the optical phonons predicted on the basis of the same model is confirmed experimentally.

The one phonon raman spectrum in microcrystalline silicon

Deep Eutectic Solvent-Mediated Synthesis of Bullet-Shaped Cerium Zinc Oxide and Sheet-Like Cerium Zinc Hydroxide Nitrate: Colorimetric and Fluorometric Detection of Pyrophosphate Ions

ABSTRACT This review is focused upon unique optical properties of rare earth (RE) doped ZnO nanostructures derived by a cost-effective sol-gel method. Doping of RE elements improves the properties of ZnO due to their special electronic structure, small crystal field splitting and partially filled 4f energy level, surrounded by full 5s and 5p orbitals. RE-element-induced defects regulate energy transfer dynamics, which can add superior features in ZnO. The biocompatibility of ZnO along with its special calibre of sustained tuneable features by RE doping makes it an excellent candidate for a highly demanding field, i.e. bio-imaging. Here, five RE elements, Tb, Ce, Gd, Y and Eu, are chosen to comprehensively review alterations in the optical parameters of ZnO by their doping. Band gap tuning and luminous properties of RE doped ZnO nanostructures, as well as their features and applications in diverse sectors, are majorly highlighted.

Band Gap Engineering and Relationship with Luminescence in Rare-Earth Elements Doped ZnO: An Overview

Fabrication of Pd nanoparticles on Al substrate with excellent superhydrophobicity and photocatalytic activity

Fabrication of La, Ce co-doped ZnO nanorods for improving photodegradation of methylene blue

Cerium-doped Zinc Oxide nanoparticles were prepared with co-precipitation method. X-Ray diffraction (XRD) analysis shows sharp peaks conforming the crystalline nature of prepared particles. Crystallite size was found from XRD peaks. A Field Emission Scanning Electron Microscope (FESEM) was used to see the particles and hexagonal shape. Spectroscopic properties were studied using a Fourier Transform-Infra Red (FT-IR) spectrometer and Raman spectrometer. Optical properties were studied using a Diffuse Reflectance Ultraviolet Visible (DRS UV–VIS), spectrophotometer. Band gap of doped particles reduces as doping concentration increases. Reduced band gap of Cerium doped particles makes them a good catalyst. There are many organic dyes which are used as coloring agents by industries like textile, printing, etc. These industries release harm full pollutants into water bodies, which effect human and aquatic life. Prepared Cerium-doped ZnO nanoparticles have proved to photodegrade Methylene Blue. Undoped ZnO nanoparticles decolorized the solution in 210 min with 81.93% efficiency. Ce (0.03 wt%) doped ZnO nanoparticles decolorized the solution in 120 min with 92.62% efficiency.

Navneetha Pujari

Papers

Photodegradation of Methylene Blue (MB) using Cerium-doped Zinc Oxide nanoparticles