Growth, spectral, thermal, electrical, mechanical and nonlinear optical properties of organic single crystal 4-Amino-(1-methylphenyl) pyridinium bromide

A recently identified organic nonlinear optical material, 4-Amino-(1-methylphenyl) pyridinium bromide (4A1MPB) was synthesized and attempts were made to grow good quality single crystal by slow evaporation solution growth technique which crystallizes in orthorhombic system with a non-centrosymmetric space group P212121. Studies such as microanalysis and powder XRD were performed for this material to ascertain its composition and phase respectively. The FT-IR spectral study, which was performed to analyze and assign the vibrational frequencies, enumerated various characteristic functional groups present in the crystal. The NLO efficiency was measured by Kurtz and Perry powder technique using Nd:YAG laser of wavelength 1064 nm and it was found to be about 0.73 times that of standard KDP material. TG/DTA and DSC analyses showed that the grown crystal was thermally stable up to about 197 °C. The UV-vis-NIR spectral data and fluorescence spectrum of the crystal were recorded to explore its optical transmission and emission properties respectively. The dielectric constant, dielectric loss, and ac conductivity of the grown crystal were evaluated as a function of frequency for various temperatures. The photoconducting nature of the grown crystal was analyzed and confirmed to be positive. The hardness studies were performed on (001) plane of the crystal at room temperature using Vickers micro-hardness tester, from which mechanical stability was analyzed through the classical Meyer's relation that revealed the moderate hardness of the title compound.