Preparation, Characterization and Structure Prediction of In2SnO3 and Spectroscopic (FT-IR, FT-Raman, NMR and UV-Visible) Study Using Computational Approach.

Unadulterated and scorch stage In2SnO3 nanopowder is effectively arranged with the doping proportion of 80-20% (In2O3-Sn) by simple sol-gel combustion direction. The material is characterized by XRD measurements and their geometrical parameters are compared with calculated values. The FT-IR and NMR spectra are recorded in both bulk and nanophase and FT-Raman spectrum is recorded in bulk phase and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (B3LYP, B3PW91 and MPW1PW91) theory in bulk phase of In2SnO3 and are compared with its nanophase. The vibrational frequency pattern in nanophase gets realigned and the frequencies are shifted up and down little bit to the region of spectra when compared with bulk phase. The UV-visible spectrum is simulated and analyzed. The frontier molecular orbital analysis has been carried out and the values of the HOMO-LUMO bandgap (Kubo gap) explore the optical and electronic characteristics of the In2SnO3. Structural studies by XRD showed the crystallite sizes of the particles. The atomic arrangement in the grain boundary seems to be somewhat different from regular periodic arrangement whereas inside the grain there is a good periodic arrangement of atoms. Above 10 mol% Sn ions, 15 mol% Sn ions, 20 mol% Sn ions to 50 mol% Sn ions form correlated clusters, 20 mol% Sn ions which lead to broadening. These EPR spectra were formed to contain two different components, one from the single isolated ions and the other from the clusters. The transition is observed for different composition increase with decreasing grain size.

Antibacterial, magnetic, optical and humidity sensor studies of ß-CoMoO4 - Co3O4 nanocomposites and its synthesis and characterization.

Cobalt Molybdate (ß-CoMoO4) and Cobalt Oxide (Co3O4) nanocomposite was prepared via co-precipitation and solid-state methods. Various techniques like powder XRD, FESEM, HRTEM, FTIR, VSM, UV-Vis and PL spectroscopy were used to investigate the structure and morphology of as prepared samples. Powder X-ray diffraction (XRD) reveals monoclinic and cubic structure for ß-CoMoO4 and Co3O4 respectively. The surface morphology was observed using field emission electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM), which shows the formation of nanocomposites at nanoscale range, the presence of elements were determined by energy dispersive x-ray spectroscopy (EDX). FTIR analysis confirms the formation and bonding nature of the samples. The anti-ferromagnetic behavior of CMCO64 composite was determined by vibrating sample magnetometer (VSM). The bandgap values were calculated by extrapolating the straight line on the energy axis (hν), and the values of ß-CoMoO4, CO3O4 and ß-CoMoO4 - CO3O4 composites were determined to be 2.20, 2.09 eV and 1.54-2.44 eV respectively. The weak blue emission peak observed at 489 nm is corresponds to crystal defects only observed in CMCO01 and CMCO64 composite, for CMCO10 the peak shifted to green region. Antibacterial studies illustrate good result for the CMCO64 composite against both Gram-negative and Gram-positive bacteria. The sensor studies were measured at different humidity environment (RH5% to RH98%). It was found that the increase in relative humidity leads to increase in the sensitivity factor of the samples. Among the samples CMCO64 composite possess highest sensitivity factor of (Sf = 4851) with response time of 60 s and recovery time of 230 s respectively.

Elucidation of photocatalysis, photoluminescence and antibacterial studies of ZnO thin films by spin coating method.

The ZnO thin films have been prepared by spin coating followed by annealing at different temperatures like 300°C, 350°C, 400°C, 450°C, 500°C & 550°C and ZnO nanoparticles have been used for photocatalytic and antibacterial applications. The morphological investigation and phase analysis of synthesized thin films well characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Photoluminescence (PL), Transmission Electron Microscopy (TEM) and Raman studies. The luminescence peaks detected in the noticeable region between 350nm to 550nm for all synthesized nanosamples are associated to the existence of defects of oxygen sites. The luminescence emission bands are observed at 487nm (blue emission), and 530nm (green emission) at the RT. It is observed that there are no modification positions of PL peaks in all ZnO nanoparticles. In the current attempt, the synthesized ZnO particles have been used photocatalytic and antibacterial applications. The antibacterial activity of characterized samples was regulated using different concentrations of synthesized ZnO particles (100µg/ml, 200µg/ml, 300µg/ml, 400µg/ml, 500µg/ml and 600µg/ml) against gram positive and gram negative bacteria (S. pnemoniae, S. aureus, E. coli and E. hermannii) using agar well diffusion assay. The increase in concentration, decrease in zone of inhibition. The prepared ZnO morphologies showed photocatalytic activity under the sunlight enhancing the degradation rate of Rhodamine-B (RhB), which is one of the common water pollutant released by textile and paper industries.