Synthesis, growth and characterization of l-Alanine Potassium Chloride single crystal: a phase-matchable semi-organic material for second and third order NLO applications

Abstract

l-Alanine Potassium Chloride single crystals have been grown by slow evaporation solution growth technique. The cell parameters were estimated from single crystal X-ray diffraction analysis and it was found that the material crystallizes in orthorhombic symmetry with space group of P2₁2₁2₁. The powder X-ray analysis proved its crystalline nature without the formation of secondary phases. The presence of functional groups and the nature of bonds appearing in the material were identified by FTIR spectroscopy. Optical constants were estimated by UV–visible spectrum and the lower cut off wavelength was observed at 330 nm. Photoluminescence emission spectrum show violet band through a strong peak centred at 380 nm. The scanning electron microscope analysis has been carried out to determine the surface morphology of the grown crystal. Energy dispersive spectrum was done to identify the composition of elements present in the title material. The second harmonic generation efficiency of the sample was confirmed and measured by Kurtz powder technique which reveals that the conversion efficiency was found to be two times that of urea crystal. Third order nonlinear optical susceptibility was identified using Z-scan technique and it is found that the crystal has a positive refractive index which is self focusing in nature. The obtained results show that l-Alanine KCl crystals are potential materials in NLO device applications.