INVESTIGATIONS ON L-VALINE DOPED IMIDAZOLINIUM L-TARTRATE (IMLT) SINGLE CRYSTALS

Abstract

Single crystals of imidazolinium L-tartrate (IMLT) crystals and L-valine doped IMLT crystals, with good optical quality, were grown by using the versatile slow cooling solution growth technique, for opto-electronic applications. The grown crystals were subjected to powder X-ray diffraction technique and the diffraction peaks were indexed. The grown crystals exhibit the monoclinic crystal structure, with the lattice parameters of a = 6.72 Å, b = 6.90 Å, c = 9.65 Å, and α = γ = 90°, β = 87.70°. The variations in the cell volume, lattice parameters, due to the doping of amino acid (L-valine) in three increasing dopant concentrations, were studied and the evolved strains were found to be tensile in character. The high transparency of the doped crystals was compared with that of the pure imidazolinium L-tartrate (IMLT), which demonstrates that the effect of dopant has enhanced the optical properties of the synthesized single crystals. The optical constant values such as bandgap energy and cut-off wavelength were also analyzed. The dielectric properties of the grown crystals i.e. the dielectric constant and dielectric loss were recorded at room temperature for both pure and L-valine doped IMLT single crystals, through which it is understood that 1 mol% L-valine doped single crystals have minimum power dissipation factor. By adopting the fourier transform infrared spectroscopic analysis the vibrational frequencies of carboxyl group and the vibrations of other intended functional groups were ascertained. The rectangular etch patterns were observed while etching the surface of the grown crystals with the water. The densities of the etch pits were found to be lesser for the 1 mol% L-valine doped single crystals when compared with other doped crystals. The existence of carbon, hydrogen and nitrogen was confirmed in the analytical carbon–hydrogen–nitrogen (CHN) study in both the doped and un-doped IMLT single crystals. It was also found that the existence of carbon, hydrogen and nitrogen have proportionally improved as the concentration of doping agent increases. The nonlinear absorption coefficient and nonlinear refractive index were estimated using the Z-scan analysis from which the third order nonlinear susceptibility was calculated.