Large size single crystals of bis(thiourea)zinc(II) chloride (BTZC), a potential nonlinear optical material, have been grown successfully by the Sankaranarayanan Ramasamy (SR) method. Powder X-ray diffraction and Fourier transform infrared analyses c
onfirmed the material of the grown crystal. Thermal stability was assessed by the thermogravimetric differential thermal analysis. The high-resolution X-ray diffraction and dielectric measurements indicate that the crystal grown by the SR method has good crystalline perfection and low density of defects.
Enhancement of second harmonic generation (SHG) efficiency and the correlation between crystalline perfection and SHG with urea doping on tristhioureazinc(II) sulphate (ZTS) single crystals have been investigated. ZTS is a potential semiorganic nonli
near optical (NLO) material. Pure and urea doped single crystals of ZTS have been successfully grown by slow evaporation solution technique (SEST). Presence of dopants has been confirmed and analyzed by Fourier transform infrared (FTIR) spectrometer. The influence of urea doping at different concentrations on the crystalline perfection has been thoroughly assessed by high resolution X-ray diffractometry (HRXRD). HRXRD studies revealed that the crystals could accomodate urea in ZTS up to some critical concentration without any deterioration in the crystalline perfection. Above this concentration, very low angle structural grain boundaries were developed and it seems, the excess urea above the critical concentration was segregated along the grain boundaries. At very high doping concentrations, the crystals were found to contain mosaic blocks. The SHG effeiciency has been studied by using Kurtz powder technique. The relative SHG efficiency of the crystals was found to be increased substantially with the increase of urea concentration. The correlation found between the crystalline perfection and SHG efficiency was discussed.
