Linear-nonlinear optical and quantum chemical studies on Quinolinium 3,5-dinitrobenzoate: A novel third order non-linear optical material for optoelectronic applications.

An organic non-linear optical (NLO) crystal of Quinolinium 3,5-dinitrobenzoate (DNBAQ) was synthesized and good quality single crystals of DNBAQ were grown by conventional slow evaporation solution growth technique. Single crystal XRD was utilized to confirm the formation of the charge transfer complex. The crystalline property and the presence of required functional groups was verified employing Powder XRD and FTIR spectral analysis. UV-Vis-NIR and Fluorescence study was performed to determine the optical transmittance and the emission property of the grown crystal. The thermal, mechanical and surface damage threshold stability of the complex was analysed using thermal studies, Vicker's micro hardness studies and Laser damage threshold measurement. The solid state parameter of electronic polarizability of DNBAQ compound was computed through dielectric studies. The non-linear optical characterizations like Kurtz Perry powder technique and Z-Scan technique ensures the non-linear optical activity of the compound. The frequency conversion efficiency of the grown crystal was estimated to be 70% that of the standard Potassium Dihydrogen Phosphate (KDP). Z-Scan analysis confirms the suitability of the grown crystal for optical limiting and switching applications. Quantum chemical studies were adopted on the optimized geometry of DNBAQ molecule using Density Functional Theory (DFT). Frontier Molecular Orbital (FMO) analysis and Molecular Electrostatic Potential (MEP) analysis were performed. The non-linear optical behaviour of the complex was established by evaluating dipole moment, polarizability and hyperpolarizability features. All the above results confirm the resourceful candidature of DNBAQ material for optoelectronic and photonic applications.