Growth, optical and thermal characterization of bis(thiourea)zinc chloride single crystals

Single crystals of nonlinear optical material bis(thiourea)zinc chloride (BTZC) were successfully grown by the temperature lowering method and also by the slow evaporation method at constant temperature 28.5 °C from its aqueous solutions having various pH values. The best quality crystal was obtained at pH value of 3.13. Studies on structural, thermal properties of the crystals have been carried out on the basis of X-ray diffraction (XRD), infrared spectroscopy (IR), differential thermal analysis (DTA) and thermogravemetric analysis (TGA). DTA study indicates the possibility of structural changes without weight loss. The values of specific heat calculated from DSC data indirectly demonstrate the high damage threshold of BTZC crystal. The crystals possess wide optical transmission window between 290 nm and 2000 nm. Kurtz powder SHG measurement confirms the nonlinear optical property of the grown crystals.