Ginson P. Joseph

Growth and Optical Studies of a Novel Organometallic Complex NLO Crystal: Tetrathiourea Cadmium(II) Tetrathiocyanato Zinc(II)

Tetrathiourea cadmium(II) tetrathiocyanato Zinc(II) (TCTZ) single crystals were grown in acetone-water mixture solvent using slow solvent evaporation technique and their optical property was studied for the first time. Both thiourea and thiocyanate ligands were combined with the transition metal ions Cd2+ and Zn2+. The nonlinear optical (NLO) efficiency of TCTZ crystal was tested and measured using Kurtz and Perry technique. The dielectric behavior of the sample was also studied.

Thermal, Optical, and Electrical Properties of Gel Grown ZMTC

The bimetallic thiocyanate of the group IIB divalent d10 ions Zn2+ and Hg2+ having unique characteristics: The pale color and high thermal stability—Zinc Mercury tetrathiocyanate (ZMTC) is chosen for growth and study. ZMTC is grown in silica gel by chemical reaction method and characterized by single crystal XRD, FTIR, FT-Raman, UV-Vis-NIR, NLO, TGA/DTG, DSC, AC conductivity, and dielectric studies. It has wide transparency window and possesses high second harmonic generation efficiency. Its thermal stability is very high. The dielectric permittivity of this material is very low.

Transparent ZnO–PVA binary composite for UV-A photo detector: optical, electrical and thermal properties followed by laser induced fluorescence

A compatible high performance UV-A sensor has been developed using poly(vinyl alcohol) (PVA)/ZnO membrane on an ITO substrate. The current challenges on UV-A photo detector have been overcome with the optimized performance of the binary composition through combining the wide-range of UV-A light photo-response, high sensitivity and quick response. This paper presents the electrical and optical properties of ZnO/PVA nanocomposites. It deals with the experimental correlation between complex optical conductivity and complex dielectric function. The ZnO filler is addressed to the modification in the band-structure, thermal properties and molecular orbital electron density. The defect states formation and laser induced fluorescence of composites were also investigated for the first time.

Investigations on the physico-chemical properties of allylthiourea complex NLO crystals

Single crystals of allylthiourea complex crystals have been successfully grown by slow evaporation technique. The grown samples were confirmed by CHN analysis. The band gap of ATCC, ATCB and ATMC were found to be 3.93 eV, 3.58 eV and 3.18 eV respectively. Thermal parameters such as of thermal diffusivity (α) and effusivity (e), the thermal conductivity (k) and heat capacity (Cp) of the grown samples were studied using phtopyroelectric technique. The frequency response of dielectric constant and dielectric loss were also studied.

Fibre optic sensor to detect heavy metal pollutants in water environments

Heavy metal ion pollution emerges as a potential threat to humankind and the ecosystem due to their increased spreading into the environment. Detection of highly toxic heavy metal ions requires rapid, simple, sensitive and selective detection methods in water environments. Optical fibre sensors facilitate the remote, continuous and in-situ detection due to their inherent properties. Herein, we report a fibre optic sensor based on evanescent wave absorption to detect heavy metal ions in water environments. Fibre optic sensor has been developed by coating dithizone on the surface of an optical fibre. Selectivity of the mercury, copper and chromium ions using dithizone has been illustrated using spectroscopy based detection approach. Effect of pH on the sensor has been investigated. The possibility of simultaneous multi-ion detection has been investigated. Copper ions concentrations in water has been detected using the developed fibre optic sensor.

Synthesis, optical and dielectric properties of highly efficient organobimetallic thiocyanate complex crystals

Single crystals of Manganese Mercury Thiocyanate (MMTC) and its lewis base adduct Manganese Mercury Thiocyanate bis dimethyl sulfoxide (MMTD) have been grown by low temperature solution growth technique. Piezoelectric charge coefficient (d33 pC/N) of MMTC and MMTD at 110 Hz was found to be 3 pC/N and 8 pC/N respectively. Hysteresis loop parameters such as remnant polarization (Pr) and coercive field (Ec) of grown samples were also determined. The mechanical behaviors of the samples were studied using Leitz Weitzler hardness tester. The band gap of the samples was also measured.

Piezoeletric and Mechanical properties of Non‐linear Optical Manganese Mercury thiocyanate (MMTC)

Single crystasls of the coordination complex non‐linear optical crystal material, MMTC with dimensions of 12×8×6 mm3 were grown from aqueous solutions by slow evaporation technique. The mechanical properties and piezoelectric properties of the crystals were studied.

Studies on the Electrical Properties of Non‐linear Optical Allyl Thiourea Cadmium Chloride (ATCB)

A potential non‐linear optical crystal material, ATCB with dimensions of 4×4×3 mm3 were grown from aqueous solutions by the conventional slow evaporation technique. The dielectric properties and electrical conductivity were determined at different temperatures. Functional groups are identified using FTIR Spectrum.