Studies on the Effect of Zinc Chloride Mixing on Bisthiourea Cadmium Chloride Crystals

Nonlinear optical Zinc mixed bisthiourea Cadmium chloride (BTCC) crystals were synthesized and grown by slow evaporation method. The FTIR analysis reveals that the C-N stretching frequencies of thiourea are shifted towards the higher frequencies for pure and Zinc mixed BTCC and the C = S stretching frequencies are shifted towards the lower frequencies for pure and Zinc mixed BTCC crystals. These observations suggest that the metals coordinate with thiourea through sulphur. UV-Vis-NIR spectra were recorded to study the optical transparency of the grown crystals. The lower cutoff wavelength is observed at 233 nm for the pure BTCC crystals. There is no comparable change in the lower cutoff wavelength for the Zinc mixed BTCC crystals. The Nonlinear Optical (NLO) efficiency of the pure BTCC crystal decreases with the increase percentage mixing of Zinc. The SHG output for BTCC mixed with 1% zinc chloride is almost 9 times greater than the SHG output obtained for Pottasium Dihydrogen Phosphate (KDP) crystal. Vicker’s microhardness test done on the experimental crystals proves their greater physical strength.