Investigation on growth and characterisation of NLO single crystals

A novel semiorganic optical material, L-alanine hydrochloride (LAH), thiourea LAH (TU-LAH) and urea LAH (U-LAH) single crystals was grown successfully by slow solvent evaporation method at room temperature of 34 °C. The crystal structure and lattice parameters were determined by single crystal X-ray diffraction analysis which shows that the grown crystals belong to orthorhombic system with the non-centrosymmetric space group P212121. XRD data of TU-LAH and U-LAH crystals show a slight change in the values of lattice parameters and volume in comparison with the pure LAH crystal indicating the inclusion of dopant urea and thiourea. The chemical composition of LAH, TU-LAH and U-LAH was established by EDAX analysis. The EDAX spectrum reveals the presence of thiourea in the TU-LAH crystal. The weight percentage (wt %) of C, N and O as obtained from EDAX analysis is in good agreement with the theoretical values. FT-IR studies confirm the presence of functional groups and the modes of vibration. The C = S stretching is observed at 820 cm-1 which confirms that the dopant has entered into the pure LAH crystal.