S. Jerome Das

Optical and spectroscopic studies of potassium p-nitrophenolate dihydrate crystal for frequency doubling applications

Non centrosymmetric potassium p-nitrophenolate dihydrate single crystals have been grown by employing the technique of slow solvent evaporation from aqueous solution by slightly adjusting the pH and growth temperature. The grown crystals have been identified from single crystal XRD analysis, FTIR and FT Raman spectroscopic techniques. The high resolution X-ray diffraction experiments substantiate good quality of the title material. Between 510 and 2000 nm, the material is observed to be nearly transparent allowing it to be explored for potential use in device fabrication. In addition, the photoluminescence spectrum of the grown crystal at room temperature shows a stable broad violet-blue emission around the 383-550 nm wavelengths with the maximum centered at 436 nm. Owing to its excellent non linear figure of merit and strong PL emission, the title crystal can have technological applications in opto-electronic devices.

Hydrothermal synthesis of zinc stannate nanoparticles for antibacterial applications

Abstract A facile and economical hydrothermal method was used to synthesise Zn2SnO4 nanoparticles with cubic spinel structure. The crystallography and optical properties of the as-synthesised nanoparticles were studied using X-ray diffraction (XRD) and UV–visible spectroscopy (UV–vis). The morphology of the nanoparticles was observed using field emission scanning electron microscopy (FESEM). The synergistic antibacterial effect of Zn2SnO4 nanoparticles against Gram-positive and Gram-negative pathogenic bacteria was investigated. These results indicate that the Zn2SnO4 nanoparticles have potent antibacterial activity against both Gram-positive and Gram-negative bacteria and can be used as a bactericidal agent to prevent and control the spread and persistence of infectious diseases.

Growth, microhardness, dielectric and photoconductivity characterization of a highly polarizable NLO material: Sodium p-nitrophenolate dihydrate (NO2-C6H4-ONa.2H2O)

Sodium p-nitrophenolate dihydrate (NPNa.2H2O) is a highly polarisable non linear optical material. It has a deff about 1.45 times than that of potassium titanyl phosphate. Single crystals of (NPNa.2H2O) have been grown successfully by slow solvent evaporation having water and methanol as solvent. The structure of the crystal is verified by single X-ray analysis. Optical absorption shows that the crystal is highly transparent between 1500 and 300 nm. Microhardness of the crystal is found to increases with increase in load and the hardness number is found to be high for methanol grown crystal as compared to the water grown crystal. Electrical conductivity as evaluated from the cole-cole plot is found to be 1.26 × 10−5 mho m−1. The dielectric constant of the crystal is low and independent at higher frequencies. The crystal has prominent photoconduction in the presence of trap energy levels formed by the Na+ ions. The SHG efficiency of the crystal is studied by performing Kurtz powder test and the results of scanning electron microscope analysis indicate that the major part of the crystal surface is free from inclusion and dislocation.

Poly[tetra­aqua­bis(μ2-2,4,6-trinitro­phenolato)barium(II)]

The asymmetric unit of the title compound, [Ba(C6H2N3O7)2(H2O)4]n, consists of a barium ion coordinated by two nitrophenolate ligands and four water molecules. Barium is decacoordinated by O atoms. These units are linked together through bridging nitro groups to form a one-dimensional polymeric chain. The three-dimensional packing is facilitated through hydrogen-bonding interactions mediated through water molecules. The coordination distances around Ba vary from 2.728 (4) to 3.138 (5) Å. The crystal sample, on exposure to air at room temperature for many days, slowly loses the water and peels out as filaments.

Growth, optical, thermal, dielectric and mechanical studies of sodium hydrogen succinate single crystal

Sodium hydrogen succinate, an alkali metallo-organic third-order nonlinear optical crystal, had been grown successfully using aqueous solution by slow evaporation technique at room temperature. Transparent single crystals were selected and subjected to single-crystal X-ray diffraction analysis to identify lattice parameters, space group and morphology. The grown crystal was further subjected to powder X-ray diffraction to analyze the crystalline quality, UV–Vis–NIR spectral analysis to reveal optical transparency, FTIR spectroscopy for confirmation of the functional group analysis and TG–DTG/DSC analysis to determine the thermal stability. The dielectric constant and dielectric loss were studied as a function of frequency at different temperatures, and the results were discussed. The mechanical properties were calculated by Vickers microhardness test, and the third-order nonlinear optical parameters such as nonlinear refractive index, nonlinear absorption coefficient and real and imaginary parts of the third-order nonlinear optical susceptibility were determined by Z-scan technique.

In vitro antibacterial and anticancer activity of copper oxide nanostructures in human breast cancer Michigan Cancer Foundation-7 cells

Objective: The use of nanoparticles (NPs) in cancer diagnosis and treatment is a rapidly developing area of nanotechnology. The main objective of this research work is to synthesize copper oxide (CuO) NPs and to investigate its vitro anticancer and antibacterial property. Methods: The CuO NPs were synthesized via a facile and cost-effective precipitation method using cupric acetate (monohydrate) (CuAc 2 .2H 2 O), sodium hydroxide, and glacial acetic acid. By varying the pH of the precursor solution, the morphology, particle size, and reaction rate of the NPs could be well tailored. The prepared CuO NPs were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, Fourier transform infrared analysis, and scanning electron microscopy. Results: The results revealed a well crystalline structure with leaf-like morphology. By controlling the pH of the solution, particle size and morphology of the NPs are altered. The synthesized CuO NPs have been screened for its antibacterial potency against Gram-positive (Methicillin-resistant Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Salmonella Paratyphi, Klebsiella pneumonia, and Enterobacter aerogenes) bacterial strains. The as-synthesized NPs were found to be remarkable in inhibiting pathogenic bacteria. The anticancer activity reveals the dose-dependent influence of CuO NPs against human breast cancer cell line Michigan Cancer Foundation-7 (MCF-7). Conclusions: The results suggested that CuO NPs have a wide range of antibacterial applications which can be used to control the spread and infection of a variety of bacterial strains. The CuO NPs showed promising anticancer activity against human breast cancer cell line (MCF-7). Overall, CuO NPs are an effective candidate for pharmaceutical, biomedical, and environmental applications.

Optical and spectral studies on pure and europium doped olgite type Na(Sr,Ba)PO4 ceramics

Europium ion doped olgite type Na(Sr,Ba)PO4 ceramics, a new generation of light emitting bulb, was prepared by a high temperature solid-state reaction method. The synthesized materials were subjected to various characterizations such as X-ray powder diffraction, Scanning electron microscopy and FT-IR spectra measurements. The EPR spectrum of the sample exhibits a well-resolved hyperfine structure of 151Eu2+ and 153Eu2+ isotopes and the g value has been calculated. Fluorescence spectra revealed that europium ions were present in divalent as well as in the trivalent oxidation states. The critical distance for energy transfer between Eu2+ and Eu2+ ion is calculated as 20Å, which is in good agreement with that of experimental data. The FTIR analysis reveals all the vibrations of PO4(3-) ions.

Investigation on the Magnetically Separable Zn Substituted CoFe2O4 Nanoparticles with Enhanced Photo-Fenton Degradation.

We report the influence of Co1-xZnxFe2O4 nanoferrites for the photodegradation of organic pollutant present in the aqueous solution. A series of Co1-xZnxFe2O4 (x = 0.01, 0.03, 0.05 and 0.10) nanoferrites have been synthesized via a facile and economically viable coprecipitation technique and investigated the effect of zinc dopant in their structural, optical, electrical and magnetic properties. X-ray diffraction and Fourier Transform Infrared spectral studies reveal the spinel phase formation of the as-synthesized nanoferrites. Photoluminescence and UV-visible spectral studies show the bandgap of nanoferrites increase from 2.47-2.67 eV and exhibited a blue shift in the band edge emission with respect to increase in Zn content. Phase transition of the samples from weak ferromagnetic to superparamagnetic nature has been observed by Vibrating Sample Magnetometer at room temperature. Furthermore, the Co1-xZnxFe2O4 was assessed for the degradation of Methylene Blue (MB) dye and the sample with Co1-0.10Zn0.10Fe2O4 showed better photocatalytic degradability of organic MB due to its enhanced adsorption in the visible region and the existence of lower concentration charge-carriers.

A High Sensitivity Isopropanol Vapor Sensor Based on Cr2O3-SnO2 Heterojunction Nanocomposites via Chemical Precipitation Route.

Cr2O3-SnO2 heterojunction nanocomposites were prepared via chemical precipitation method. The prepared samples were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra and Field Emission Electron Microscopy (FESEM). The XRD spectrum confirms the presence of both tetragonal rutile SnO2 and rhombohedral corundum Cr2O3 structure. Further investigation into the gas sensing performances of the prepared Cr2O3-SnO2 nanocomposites exhibited an enhanced sensitivity towards VOPs such as isopropanol, acetone, ethanol and formaldehyde. Especially, isopropanol vapor sensor shows excellent sensitivity at an operating temperature of 100 °C. The highest sensitivity for Cr2O3-SnO2 heterojunction nanocomposites indicate that these materials can be a good candidate for the production of high-performance isopropanol sensors.

Study of Structural, Optical, Dielectric and Magnetic Properties of Zinc Ferrite Synthesized by Co-Precipitation

Spinel zinc ferrite (ZnFe2O4) nanoparticles have engrossed immense attention due to its unusual amalgamation of its properties especially the magnetic properties and these properties are catered as fitting candidates in the field of electronics. Nanostructured spinel zinc ferrite particles were synthesized using scalable co-precipitation technique. The morphology, particle size and reaction pace of the nanoparticles (NPs) were fine tuned by eco-friendly technique. These NPs were characterized by UV-Visible spectroscopy (UV-Vis), photoluminescence (PL), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Transmission electron microscopy (TEM), vibrating sample magnetometer ((VSM) and Dielectric studies. The required profiles were confirmed by XRD and FTIR spectra, UV-Vis, PL spectral studies. Further these measurements divulge the significance of optical properties and the spectral parameters are used to appraise the optical constants required for fabrication. Transmission electron microscopy eventually discloses the morphological analysis of the synthesized ZnFe2O4 nanoparticle as 15 nm within the scaling limitations. Using, VSM, the magnetic behaviour of the material have been determined as a function of magnetic field at ambient temperature; the magnetic measurements well-establishes the magnetic property and disclosed to have weak ferromagnetic behaviour as the crystallite size decreases. The A.C. conductivity measurements and dielectric studies were done as a functional dependence of frequency and temperature on synthesized nanoparticles.