Remarkable effect of L-Ascorbic acid on crystal morphology, structural, crystalline perfection, optical, photoluminescence and dielectric properties of Zinc(tris) thiourea sulphate (ZTS) single crystals

Large size growth of Zinc(tris) thiourea sulphate (ZTS) crystals has been successfully done through slow solvent evaporation technique in presence of L-Ascorbic acid (LAA). The possibility of any extra phase due to presence of LAA was ruled out through structural analysis. The deviation in lattice parameters and shift in peaks position indicates the interaction of LAA with ZTS. Crystalline perfection of grown crystals was judged by High-resolution X-ray diffraction (HRXRD) study and found that the crystalline perfection of ZTS in presence of 10 wt% LAA is enhanced compared to others. The low optical absorbance and high band gap confirms its application in optoelectronic devices. A burly blue emission band at 460 nm was observed in Photoluminescence spectra of ZTS crystals grown in presence of LAA when excited at 310 and 358 nm both. However, when these specimens were excited at 385 nm this blue emission band is observed at 470 nm. The remarkable enhancement of blue band emission intensity was noted which may be attributed due to presence of defects (color centers). Further the dielectric measurement was done and shows that the dielectric constant has been improved due to presence of LAA. The enhanced optical band gap, photoluminescence intensity and dielectric constant suggests that the LAAZTS single crystals are suitable for electro-optic device applications.