Structural, optical, dielectric, mechanical and Z-scan NLO studies of charge transfer complex crystal: 3-aminopyridinum-4-hydroxy benzoate

The single crystals of 3-aminopyridinium-4-hydroxy benzoate (APHB) (3 × 3 × 2 mm³) has been grown by the slow evaporation technique with methanol as solvent at 30 °C. Formation of the crystal has been confirmed by the single crystal X-ray diffraction (SXRD) analysis. APHB crystal crystallize under monoclinic P21/c and cell parameters a = 12.025(12) Å, b = 9.288(9) Å, c = 11.353(11) Å. The presence of various functional groups in APHB was confirmed by fourier transform infrared (FTIR) spectral analysis. UV–Visible absorption and transmittance spectra have been recorded in the region between 400 and 800 nm. It is found that the attainment of high value (ε_T) at lower frequency is due to the space charge polarization in the materials. The mechanical strength of the crystal has been studied by using a Vickers’ microhardness test. The stiffness constant and yield strength of the crystal also were calculated from the microhardness test. The third order nonlinear optical parameters like refractive index, absorption coefficient and third order susceptibility were estimated by Z-scan studies. The grown crystal APHB has adopted the step wise growth pattern having hexagonal-shaped striations, which was confirmed from the etching technique.