Growth and characterization of NLO crystal: L-leucine phthalic acid potassium iodide

A new semi-organic non linear optical crystal, L-leucine phthalic acid potassium iodide (LLPPI) has been grown from an aqueous solution by slow evaporation method. The grown crystals were subjected to different characterizations, such as single crystal XRD, FT-IR, UV-Vis, TGA, SEM, EDAX, micro hardness, dielectric and powder SHG. Single crystal structure was determined from X-ray diffraction data and it revealed that the crystal belongs to triclinic system with the space group P1. The vibrational frequencies of various functional groups were derived from FT-IR spectrum. Thermal stability of the grown crystal was investigated by TG-DTA studies and it was observed that the crystal was thermally stable up to 192 °C. Optical absorption study was carried out and a good transparency in the entire visible region was observed at the lower cutoff wavelength of 227 nm. Dielectric study was performed as a function of frequency and normal dielectric behavior was observed. The micro hardness test was carried out and the load dependent hardness was measured. Kurtz powder method was employed to explore the NLO characteristics of the grown crystal.