Crystal growth and characterization of an efficient semi-organic nonlinear optical (NLO) donor-π-acceptor single crystal: 2-amino-5-nitropyridinium nitrate (2A5NPN) grown by slow evaporation solution technique (SEST)

Abstract

The semi-organic nonlinear optical 2-amino-5-nitropyridinium nitrate (2A5NPN) single crystals were successfully grown by slow evaporation solution technique with the dimension of 10 × 10 × 10 mm3. The crystalline structure of 2A5NPN was confirmed by single crystal X-ray diffraction measurement. The optical quality of the grown crystal was studied using UV–Vis–NIR spectrum analysis. It shows that the grown crystal has 69% of transmittance with the lower cut-off wavelength of 404 nm. The refractive index of 2A5NPN single crystal was calculated using the Prism-coupling method. The thermal diffusivity was analyzed using photoacoustic measurement. The dark and photoconductivity of the grown crystal were analyzed and the result shows that the crystal has negative photoconductivity nature. The mechanical strength of 2A5NPN crystal was analyzed by Vickers microhardness tester and the hardness number ( $${H_v}$$ ), Meyer’s index (n), yield strength (σy), stiffness constant (C11) and Hays–Kendall relation were evaluated. The fundamental solid state parameters such as valence electron plasma energy (ћωp), Penn gap (Ep), Fermi energy (Ef) and various type of electronic polarizability (α) of the grown crystal were determined using the dielectric parameters. The HOMO–LUMO energy and first-order hyperpolarizability (β) of 2A5NPN molecule were calculated in the gas phase by density functional theory. The laser damage threshold measurement has been performed and it reveals that the optical damage tolerance power of the grown crystal is high compared to other organic and inorganic NLO crystals. The third-order nonlinearity of 2A5NPN was assessed using an open and closed aperture Z-scan technique. The above results show that 2A5NPN crystal is a potential candidate for nonlinear optical device applications.