Investigations on the growth, spectral, optical, hirshfeld surface, electrical, thermal and nonlinear optical properties of 4-aminopyridinium 4-carboxybutanoate single crystal

Centro-symmetric 4AP4CB crystal with monoclinic crystal system analyzed by powder X-ray diffraction. The finger print plots of Hirshfeld surface analysis indicate that the crystal packing is dominated by H–H hydrogen bonds and Fourier transform infrared spectroscopy confirms the presence of active functional group. From UV–visible analysis, optical constants of 4AP4CB crystal such as absorption coefficient (α), energy band gap (E_g = 4.38 V), extinction coefficient (K), reflectance (R), refractive index (n = 1.4599), electrical conductivity (σ_electrical) and optical conductivity (σ_optical) were determined for suitability of NLO applications. The emission band gap determined as 3.07 eV from Photo luminescence spectroscopy. The electro chemical band gap calculated as 3.39 eV from cyclic voltammeter. At 308 K, the dielectric investigation identified the electric field response for the grown 4AP4CB crystal. Absorption, emission and electrochemical band gap of 4AP4CB were determined. Vickers’s micro hardness test indicates that the 4AP4CB crystal is a soft material. The thermal stability of the grown crystal is 62 °C studied from thermo gravimetric and differential thermal analysis for optoelectronic applications. The second harmonic generation test using the Kurtz-power technique revealed that the polarization led to 2.2 times the SHG efficiency of standard KDP.