Abstract
Due to high nonlinearity and excellent optical properties of single crystal Zinc (tris) Thiourea Sulphate (ZTS), it is regarded as a key contender for hi-tech applications. Keeping that in mind, the present work aim is to grow good quality single crystals of pure and Congo red dye doped ZTS by slow evaporation solution techniques at the ambient conditions. Then, the strong influences of the dye doping on the physical properties of the ZTS crystal is going to be investigated. The effect of the dye on the crystal structure and phases of the ZTS was confirmed by the powder X-ray diffraction analysis. FT-Raman as a further study reveals that there are no phase changes due to doping; however, it approves the presence of all vibrational modes with minute shifting due to dye doping. The quantitative and qualitative analyses of composition and building qualities were performed by SEM/EDXS and showed that the ZTS crystal quality has been actually enhanced due to the dye doping. Optical transparency of the doped crystal is also enhanced as compared to the pure ZTS crystal and a new absorption band at similar to 495 nm has been created due to dye doping. Minute changes in band gap as well as a new band gap (similar to 2.42 eV) were observed due to the dye doping in the crystalline matrix of the ZTS. Photoluminescence (PL) analysis at ambient temperature revealed that both pure and CR doped ZTS have two emission peaks, a sharp one at similar to 408 nm and abroad peak at similar to 430 nm, respectively. However, the intensity of the PL emission was found to be enhanced due to the CR dye doping in the crystalline matrix of the ZTS. The dielectric study showed that the dielectric constants of the ZTS are enhancing due to the dye doping, while; the low dielectric loss confirmed the existence of only the trivial defects in the grown crystals. All obtained results along with dielectric studies indicated that the Congo red doping has, in fact, improved the optoelectronic properties of the ZTS crystal and may render it as a potential material for opto-electrical devices and applications.