Synthesis, growth and physicochemical characterization of 8-hydroxyquinolinium 3,4 dimethoxybenzoate, a novel organic nonlinear optical single crystal

In our work, a novel organic single crystal, 8-hydroxyquinolinium 3,4-dimethoxybenzoate (8-HDMB) was synthesized by the slow evaporated solution growth technique that uses ethanol: acetone as a mixed solvent. The crystal structure, cell dimensions, and space group were experimentally determined using the single-crystal X-ray diffraction (XRD) technique where the 8-HDMB compound crystallizes in the triclinic crystal system. The presence of various functional groups and their vibrational modes were confirmed by the Fourier transform infrared (FTIR) and laser Raman spectroscopic analyses. The optical transparency was examined within the wavelength range of 100–800 nm and the energy-gap was calculated. Moreover, the linear optical studies provide information about the wide transparency window in the UV region with the 306 nm as the lower cut off wavelength and 3.65 eV as the optical bandgap. The thermal stability of 8-HDMB was found to be up to 130 °C, while the mechanical properties by the Vickers microhardness test confirmed for its hardness against the applied loads. Further, the quantitative and qualitative analysis provided the photoluminescence properties and with the use of the Kurtz–Perry powder procedure, the enhanced SHG (second harmonic generation) efficiency of 8-HDMB grown crystal was investigated.