Studies on cadmium based metal organic crystals

Abstract

Bis(thiourea)cadmium chloride (BTCC) is a novel semiorganic nonlinear optical (NLO) material for efficient frequency doubling of Nd:YAG laser. BTCC crystal has good transmission in the entire visible region and is 110 times more nonlinear than quartz. Bis(thiourea)cadmium iodide (BTCI) is another novel semiorganic NLO material found to be a good candidate for electrooptic modulators. With an aim of discovering new useful materials, we have grown by the free evaporation method and characterized pure and mixed crystals of BTCC and BTCI [(BTCC)x (BTCI)1-x with x = 1.0, 0.8, 0.6, 0.5, 0.4, 0.2 and 0.0] and urea doped (0.25, 0.50, 0.75 and 1.0 mol% doped) BTCC single crystals. newline newline Single crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) measurements were carried out to characterize the grown crystals structurally. The important groups associated with the sample crystals were identified and their respective bands were assigned by carrying out the Fourier transform infrared (FTIR) spectral studies. Energy dispersive X-ray spectra were recorded to understand the chemical composition of the crystals grown. All the grown mixed crystals were subjected to thermogravimetric (TG) and differential thermogravimetric analyses (DTA) inorder to understand the thermal behaviour. Optical behaviour of the grown crystals were studied by UV-Vis-NIR spectral analysis and Second Harmonic Generation (SHG) efficiency measurements. newline newline DC and AC electrical measurements were carried out by the two probe method and parallel plate capacitor method respectively. Measurements were carried out at various temperatures ranging from 30-100and#61616;C. DC conductivity (and#61555;dc) and DC activation energy (Edc) were determined. The dielectric parameters (and#61541;r, tan and#61540; and and#61555;ac) and AC activation energy (Eac) were also determined.