Growth and characterization of 4-methyl-3-nitrobenzoic acid (4M3N) single crystal by using vertical transparent Bridgman-Stockbarger method for NLO applications

Organic, third order nonlinear optical (NLO) 4-methyl-3-nitrobenzoic acid (4M3N) single crystal was successfully grown by vertical transparent Bridgman - Stockbarger method. The crystal structure and unit cell parameters of 4M3N single crystal were analysed by using single crystal X-ray diffraction (SXRD) analysis. The functional groups present in the grown 4M3N crystal have been identified by FTIR spectral analysis. 4M3N single crystal exhibits high optical transmittance (80%) in the Visible to near IR region and the cut-off wavelength is observed at 414 nm. The optical bandgap value is calculated from the Tauc plot analysis. The luminescence properties of the grown crystal were examined from the photoluminescence (PL) spectrum. Mechanical stability of 4M3N single crystal was carried out by Vickers microhardness test and it belongs to soft material category. The energy density value of 4M3N was compared with other standard organic single crystals. The third order nonlinear optical values were calculated from the Z-scan experiment. The optimized geometry, polarizability and hyperpolarizability, frontier molecular orbitals (FMO), Mulliken's charge, natural bond orbital (NBO) and molecular electrostatic potential (MEP) were investigated. Hirshfeld surface (HS) and 2D finger print plot of 4M3N single crystal were generated by using Crystal Explorer 3.1 software and it is deliberated by the intermolecular interaction of the crystal structure.