Experimental and computational studies on optical properties of a promising N-benzylideneaniline derivative for non-linear optical applications

A new organic non-centrosymmetric nonlinear optical (NLO) material, p-nitrobenzylidene-p-phenylamineaniline (PNBPDA) was synthesized and single crystals of PNBPDA were grown from ethanol solution by slow evaporation solution growth technique. Single crystal X-ray diffraction (XRD) and powder XRD data confirm that PNBPDA crystallizes in monoclinic system with noncentrosymmetric space group Cc.Various characterizations like PXRD, fourier transform infrared (FT-IR) spectroscopy, thermal analysis and micro hardness test have been conducted. Optical studies have been done for evaluating the transparency range and the luminescence property of the grown single crystals of PNBPDA. Dielectric studies have carried out to investigate the electronic polarizability within the grown crystal. The frequency conversion efficiency of the grown crystal was determined using Kurtz Perry powder technique and second harmonic generation (SHG) was found to be 6 times that of standard Potassium Dihydrogen Phosphate (KDP). Z-Scan technique was performed to determine the third order non-linear optical properties of the grown crystal of PNBPDA. The optical limiting property and the laser damage threshold value reflect the practical applicability of PNBPDA crystal for photonic applications. Additionally, the theoretical background of PNBPDA was carved out using Density Functional Theory (DFT) by evaluating the geometrical and electronic structural properties from Frontier Molecular Orbital (FMO) analysis, Molecular Electrostatic Potential (MESP) analysis and non-linear features from dipole moment, polarizability and hyperpolarizability properties embedded within the PNBPDA molecule. The calculated first order hyperpolarizability (beta) value of the molecule was found to be 14 times that of the standard urea molecule.