Impact of L-Leucine on the structural and optical properties of potassium dihydrogen phosphate (KDP) crystals

Abstract

IntroductionPotassium Dihydrogen Phosphate (KDP) is an exceptionally good non-linear optical (NLO) material used for optoelectronics, electro-optics, etc. The inclusion of amino acids enhances the properties of KDP because amino acids have properties like molecular chirality and zwitterionic nature. ObjectiveIn this study, our primary goal was to describe the effects of L-Leucine doping on KDP and to study the changes in its optical and structural properties for different applications related to non-linear optics. MethodsPure KDP and L-Leucine doped KDP (1 mol% and 2 mol%) crystals were grown using the slow evaporation method at room temperature. The crystals have been characterized using Powder X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) Spectroscopy, Ultraviolet-Visible (UV-Vis) Spectroscopy, Photoluminescence (PL) Spectroscopy and Relative Second Harmonic Generation (SHG) measurement. ResultThe FTIR spectroscopy confirms the presence of amino acid, L-Leucine in KDP as implied by functional groups. The UV-Vis spectroscopy helps with the optical transparency of crystals and the bandgap of pure KDP was observed to be enhanced with the addition of L-Leucine. The PL spectra confirm the existence of point defects in the grown crystals. Furthermore, L-Leucine doping in KDP improves its relative SHG efficiency. ConclusionIt has been seen those optical properties of pure KDP is immensely improved with the addition of L-Leucine without altering the KDP lattice.