SYNTHESIS, GROWTH AND CHARACTERIZATION STUDIES OF p-HYDROXYBENZOIC ACID ADDITION WITH THE GUANIDINIUM CARBONATE SINGLE-CRYSTALS

An organic nonlinear optical (NLO) crystal of Guanidinium carbonate (GUCT) was synthesized by the slow evaporation solution growth method using water as solvent. The GUCT crystalized in the tetragonal crystal system with non-centrosymmetric space group P43212, which has been confirmed by single-crystal X-ray diffraction. The crystalline perfection of the grown crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. The UV-Vis-NIR spectrum studies have been carried out to identify the optical transmittance, lower cut off wavelength and optical band gap energy of GUCT crystal. The luminescence spectrum of crystal contains a green emission band with λmax, 545 nm. From thermo-gravimetric analysis (TGA), the thermal stability of the grown crystal is found to be 117°C. The dielectric tensor components ε11 and ε22 of the grown crystal were evaluated as a function of frequency at 40°C. The mechanical strength and its parameters of the grown crystals have been determined by Vickers' microhardness test. The Kurtz-powder technique reveals that the second harmonic generation (SHG) efficiency of the grown crystal is 5.2 times greater than that of KDP.