Study of growth condition and characterization of bisthiourea–zinc acetate (BTZA) crystal grown in silica gel

Abstract Semiorganic crystals of bisthiourea–zinc acetate (BTZA) having nonlinear optical properties was grown in silica gel medium by gel technique at room temperature. The optimum pH, yielding maximum size (35 mm) of transparent title crystal was found to be 4.8 pH. Single crystal XRD analysis reveals that the crystal lattice of BTZA crystal belongs to monoclinic system with cell parameter, a = 7.1243 A, b = 17.7292 A and c = 11.1372 A. The presence of functional groups in the crystals was confirmed by FTIR analysis, and also the presence of elements in the compound was identified by EDAX. The optical constants (lower cutoff wavelength λ = 297 nm, band gap energy = 4.4022 eV) were determined using the recorded UV–Vis–NIR spectrum of BTZA crystal. A surface feature of the crystal was analyzed using AFM (Atomic Force Microscope). The Vickers microhardness number was found to increase with increasing load, and the yield strength ( σ y ), elastic stiffness constant ( C 11 ) of BTZA crystal were calculated. The laser damage threshold was measured using Nd:YAG laser (1064 nm). The dielectric properties of BTZA crystal was recorded in the frequency range of 50 Hz–5 MHz, and it shows that the dielectric constant and dielectric loss is found to be decreased with an increase of frequency at various temperature. Further, the valence electron, plasma energy and electronic polarizability for the gel grown BTZA crystal was calculated. Thermal behavior of the gel grown crystal was investigated by thermo gravimetric and differential scanning calorimetric analysis.