Growth, linear- nonlinear optical studies and quantum chemistry formalism on an organic NLO crystal for opto-electronic applications: experimental and theoretical approach

An organic non-linear optical material of 4-methylanilinium 3,5-dinitrobenzoate (MADNBA) was synthesized and crystals of MADNBA were grown by employing slow evaporation solution growth technique. The crystal structure was confirmed from Single crystal XRD. Grown crystals were characterized by Powder XRD, UV-Vis-NIR, Photoluminescence and Laser damage threshold measurement studies. Infrared spectroscopy, thermal analysis and microhardness measurement were performed to study the molecular vibration, thermal behaviour and mechanical stability of the grown crystal. Dielectric studies have been performed to evaluate various solid state parameters. From the Kurtz Perry powder technique, it was found that Second harmonic generation efficiency of the obtained compound is 10 times that of the standard potassium dihydrogen phosphate. Z-Scan technique was also carried out to investigate the non-linear activity and optical limiting behaviour of MADNBA crystal. Computational analysis performed upon the optimized geometry of MADNBA molecule using Density Functional Theory confirmed the experimentally determined quantities under a strong theoretical background. Frontier molecular orbital analysis and molecular electrostatic potential analysis were carried out. The non-linear character of the compound was also determined by computing various non-linear optical parameters like dipole moment, polarizability and hyperpolarizability. The first order hyperpolarizability (beta) value of the MADNBA molecule was evaluated to be 8 times that of the standard urea molecule. Based on these results, it could be proposed that MADNBA material serves as a potential candidate for frequency doubling, optical limiting and photonic applications in optoelectronics domain.