Studies on crystal growth, vibrational and optical properties of organic nonlinear optical crystal: p-Aminoazobenzene

p-Aminoazobenzene (p-AAZB), an organic nonlinear optical (NLO) crystal having good optical quality has been grown by slow evaporation solution technique using ethanol as a solvent. Solubility studies were performed at different temperatures. The structural characterization of the grown crystals was carried out by X-ray diffraction. Group theoretical analysis was carried out to calculate the number of modes of vibration. The lowering of the wave numbers of azo group suggests the existence of strong intermolecular N–H⋯H hydrogen bonding. This has been analysed based on the vibrational spectral features. Optical absorption studies show the effective transmission in the entire UV–vis region. The second harmonic generation results show the suitability of this material for NLO applications.