Zinc Tris-thiourea Sulphate Crystals Research Articles

Growth and Investigation Studies of Pure and Glycine Doped Zinc Tris-thiourea Sulphate (ZTS) Single Crystals

Abstract: Zinc Tris-thiourea Sulphate (ZTS) belongs to the family of semiorganics nonlinear optical materials. Good quality single crystal of pure and doped ZTS have been grown by slow evaporation solution growth technique at room temperature. The grown crystals have been subjected to FTIR and UV visible spectra studies. The Fourier Transform Infrared analysis confirms the presence of functional groups and zinc coordination in grown crystals. The UV visible spectrum revels that grown crystals were transparent in the entire visible region. These investigations indicated that impurity played an important role in the changes of the transmittance of ZTS crystals.

Influence of cobalt-doping on the optical properties of zinc tris–thiourea sulfate (ZTS) single crystal

Zinc tris-thiourea sulfate (ZTS) single crystals, pure and doped with different concentrations of cobalt, were synthesized and grown by the slow evaporation technique of supersaturated aqueous solutions at 315 K. Co2+ concentration in the solution was 2, 4 and 6 mol%. Optical transmittance was measured for the obtained crystals as a function of wavelength in the range of 190–900 nm. The present investigation shows that doping ZTS crystal with Co2+ modifies its optical properties. The absorption coefficient of ZTS crystal exhibits an exponential dependence on photon energy following Urbach relation. Doping ZTS crystal with Co2+ changes the values of optical transmittance, cut off wavelength, absorption coefficient, optical energy gap, Urbach tail energy and steepness parameter. The changes are systematic i.e. the mentioned optical parameters increase or decrease continuously with increasing Co2+ concentration in the growth solution. The electrical conduction of ZTS crystal is increased with cobalt doping. The Urbach tail energy changes reversely with the optical energy gap.

Growth and investigation of pure and sodium iodide-doped zinc tris-thiourea sulphate (ZTS) single crystals

Single crystals of pure and sodium iodide NaI-doped zinc tris thiourea sulphate (ZTS) were grown by slow evaporation technique at room temperature from aqueous solution. Powder XRD analysis of the grown crystals reveals orthorhombic structures with space group Pca21. The functional groups and modes of vibrational frequencies were recognized with FTIR spectral analysis. UV–Visible spectra indicate that the material has high optical transparency in the entire visible region. The hardness of the material studies reveal that the hardness number (Hv) increases with load for both pure and NaI-doped ZTS crystals. The thermal properties of the grown crystals were investigated by thermo-gravimetric and differential thermal analysis techniques (TGA/DTA).

The effect of Ammonium Molybdate on mechanical property of Zinc (tris) Thiourea Sulfate (ZTS) crystal: A Novel NLO crystal

Zinc tris-Thiourea sulfate (ZTS) is one of the notable semi organic non linear optical crystals. In the present investigation 0.01N Ammonium Molybdate doped ZTS crystal was grownusing single diffusion gel growthtechnique which has an advantage over normally employed solution growth method, in terms of controlled nucleation and hence better perfection. A significant morphological alteration was observed due to doping. The functional groups of pure and doped ZTS crystals were recorded and identified using Fourier Transform Infrared Spectroscopic (FTIR) analysis. A study on hardness variation due to doping was conducted using Vickers' Hardness Tests. The increase in hardness observed can be assigned to the impurity hardening effect as found to increased due to effect of dopant. The results obtained are elaborated and discussed in the paper.

Influence of Nd3+ on zinc tris-thiourea sulphate single crystal: a comparative crystal growth, structural, linear–nonlinear optical and dielectric study to explore NLO device applications

In present investigation, crystals of pure and Nd3+ doped zinc tris-thiourea sulphate (ZTS) material have been grown from aqueous solution at room temperature by employing slow evaporation technique. The incorporation of Nd3+ in ZTS crystal complex has been qualitatively determined by means of energy-dispersive spectroscopic technique. The crystalline phase and structural parameters of grown crystals have been confirmed by powder X-ray diffraction technique. The influence of Nd3+ on optical transparency of ZTS crystal has been examined in the range of 190–1100 nm. The transmittance data have been used to evaluate the vital optical constants (extinction coefficient, refractive index and reflectance) of grown crystals to discuss the utility for distinct optical applications. The enhancement in SHG efficiency of Nd3+ doped ZTS crystal has been confirmed by Kurtz–Perry powder test. The nature of dielectric constant and dielectric loss of pure and Nd3+ doped ZTS crystal has been comparatively investigated in the temperature range of 35–110 °C.

The effect of hippuric acid on crystal growth, structural and optical properties of ZTS single crystals

Zinc tris thiourea sulfate (ZTS) is one of the promising semiorganic crystals useful for nonlinear applications. The effect of hippuric acid doping on the growth aspects, structural and optical properties of ZTS crystal was investigated. Slow evaporation technique was employed to grow pure and 1mol% hippuric acid doped ZTS (HAZTS) single crystals. Powder XRD analysis reveals the crystalline nature of the grown crystals. Both the crystals exhibit orthorhombic crystal structure. The lattice parameters of the grown crystals are: a=11.0466Å, b=7.6949Å and c=15.6393Å (for pure ZTS); a=11.1302Å, b=7.7081Å and c=15.5033Å (for HAZTS). The UV–vis–NIR spectral analysis was carried out to study the effect of doping on the optical characteristics of the grown crystals. The crystal is transparent over the entire visible region. The bonding structure and molecular associations were analyzed by FTIR spectroscopy. Powder SHG test reveals the non-linear optical efficiency of the grown crystals.

An in situ AFM investigation on the morphology of the (100) growth interface of ZTS crystal

Interface morphology of the (100) face of zinc tris-thiourea sulphate (ZTS) crystals, grown under different supersaturations, at 30°C, was investigated using in situ atomic force microscopy (AFM). It comes out that the (100) face exhibits stepped surface characteristics. At lower supersaturations, nucleation easily occurred at the outcrops of edge dislocations which could act as persistent sources of monomolecular growth steps, and the edge dislocation sites appeared to exhibit a “memory function”. At higher supersaturations, however, poly-nucleation becomes the primary growth mechanism. The rates of step advancement in the [010] and [001] directions of the two-dimensional nuclei were different, as it ensues from the symmetry anisotropy. The activation energy of the two-dimensional nuclei along with the step kinetic coefficients in the [010] and [001] directions, were calculated. We also found that microcrystals on the surface of the crystal could be better integrated into the crystal surface, or otherwise lead to the generation of pits by migration of the microcrystals. Pits could be gradually filled by elementary steps and thus no defect would be formed, or they might also be covered directly by macrosteps, which would result in liquid inclusions.

Growth and Characterization of Pure and Cd-Doped Zinc Tris-Thiourea Sulfate (ZTS) Single Crystals

Single crystals of pure and Cd-doped zinc tris-thiourea sulfate (ZTS) were grown for frequency conversion applications by a low temperature solution growth method, allowing slow evaporation of the water solvent at a constant temperature. The solubility of ZTS was found to increase with the concentration of Cd in the aqueous solution. The optical transparency was found to increase in the Cd-doped crystals as compared to that in the undoped crystals. The doping of Cd was confirmed quantitatively by the atomic absorption spectroscopy and qualitatively by Fourier transform infrared spectroscopy. From the powder x-ray diffraction study, it was found that the lattice constants (a, b and c) decrease with the concentration of Cd in ZTS, but the change in the crystal symmetry and space group has not been reported. A␣change in growth habit of Cd-doped crystals has been observed. Thermo-gravimetric and differential thermal analysis was employed to learn the thermal stability of the grown crystals, and 2 mol% Cd-doped ZTS crystal was found to thermally stable up to 230 °C. The second harmonic generation (SHG) efficiency measurement reveals improvement in the SHG efficiency, as 4 mol% Cd-doped ZTS crystal has 1.36 times more SHG efficiency as compared to the pure ZTS crystal.

Influence of temperature on the optical properties of zinc tris-thiourea sulfate (ZTS) single crystal

Single crystal of zinc tris-thiourea sulfate (ZTS) was synthesized and grown by the slow evaporation technique at 315K. The effect of temperature on the optical properties of ZTS crystal was studied in the temperature range 293–338K. This range involves the first-order phase transition temperature from ferroelectric to paraelectric phase (323K). At room temperature (293K), the optical transmittance (T) has high values in the completely visible wavelength range. The cut off wavelength equals to 278.5nm at room temperature. By increasing temperature, the optical transmittance decreases, however the cut off shifts to higher wavelengths. These changes have different rates in the two phases (ferroelectric and paraelectric). Analysis reveals that the type of transition is the direct allowed one. The optical energy gap (Eg) has the value of 3.89eV at room temperature. This value decreases linearly with increasing temperature by different rates in the two phases. In the region of the absorption edge, the absorption coefficient obeys Urbach’s rule, and Urbach parameters were calculated. The Urbach tail energy (Ee), which equals to 1.024eV at room temperature, increases linearly with increasing temperature. This change has different rates in the two phases. At room temperature, the steepness parameter (σ) has the value of 24.697×10−3. It decreases linearly with increasing [1/(Temp.)2] by different rates in the two phases. For all studied parameters, the temperature dependence relations change considerably while passing through 323K. This anomalous behavior confirms that the transition from ferroelectric to paraelectric phase occurs at this temperature.

The Effect of Phosphate Mixing on Structural, Spectroscopic, Mechanical and Optical Properties of Zinc tris Thiourea Sulphate (ZTS) Single Crystals

Zinc tris Thiourea Sulphate (ZTS) is a semi organic non-linear optical crystal. The ZTS and phosphate mixed (in different mol %) ZTS crystals have been grown from aqueous solution using the slow evaporation method. Single crystal XRD were carried out for ZTS and phosphate mixed ZTS crystals to determine cell parameters. FTIR analysis identified modes of vibrations of different molecular groups and confirms the presence of phosphate ion. The UV-Vis-NIR spectrum shows that the material has wide optical transparency in the entire visible region. The second harmonic generation (SHG) was confirmed by Kurtz powder method. It is found that 10 mol % of phosphate mixed ZTS crystal has better SHG efficiency than pure ZTS crystal. The Vicker microhardness test was carried out on the grown crystals and Vicker’s Hardness Number was found increase with increase in phosphate mixing.

Synthesis, growth and studies of undoped and sodium chloride-doped Zinc Tris-thiourea Sulphate (ZTS) single crystals

Single crystals of undoped (pure) and sodium chloride (NaCl)-doped Zinc Tris-thiourea Sulphate (ZTS) were grown from aqueous solutions by slow evaporation technique. Morphological alterations have been observed when NaCl is doped into ZTS crystals. Density of the grown crystals was measured by floatation method. The values of unit cell parameters from single crystal X-ray diffraction (XRD) studies show that pure and sodium chloride-doped ZTS crystals are in orthorhombic structure. Impurity concentration in the doped crystals was estimated by using an atomic absorption spectrometer. Second Harmonic Generation (SHG) test for the undoped and NaCl-doped ZTS crystals was performed by the powder technique of Kurtz and Perry using a pulsed Nd:YAG laser. Microhardness studies show that hardness number ( H v ) increases with load for all the grown crystals of this work. From the values of work hardening coefficients, it is concluded that pure and sodium chloride-doped ZTS crystals belong to the category of soft materials. UV–vis–NIR spectra show that the grown crystals have wide optical transparency in the entire visible region. Birefringence studies of the grown samples have been performed by channelled spectrum method. The thermal stability of the materials is found to be increasing with the doping concentration of sodium chloride (NaCl) in the lattice of ZTS crystals.

Growth and characterization of pure and potassium iodide-doped zinc tris-thiourea sulphate (ZTS) single crystals

Abstract Single crystals of pure and potassium iodide (KI)-doped zinc tris-thiourea sulphate (ZTS) were grown from aqueous solutions by the slow evaporation method. The grown crystals were transparent. The lattice parameters of the grown crystals were determined by the single-crystal X-ray diffraction technique. The grown crystals were also characterized by recording the powder X-ray diffraction pattern and by identifying the diffracting planes. The FT-IR spectrum was recorded in the range 400–4500 cm −1 . Second harmonic generation (SHG) was confirmed by the Kurtz powder method. The thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) studies reveal that the materials have good thermal stability. Atomic absorption studies confirm the presence of dopant in ZTS crystals. The electrical measurements were made in the frequency range 10 2 –10 6 Hz and in the temperature range 40–130 °C along a -, b - and c -directions of the grown crystals. The present study shows that the electrical parameters viz. dc conductivity, dielectric constant, dielectric loss factor and ac conductivity increase with increase in temperature. Activation energy values were also determined for the ac conduction process in grown crystals. The dc conductivity, dielectric constant, dielectric loss factor and ac conductivity of KI-doped ZTS crystal were found to be more than those of pure ZTS crystals.

Growth and studies of pure and potassium iodide-doped zinc tris-thiourea sulphate (ZTS) single crystals

Single crystals of pure and potassium iodide (KI)-doped Zinc Tris-thiourea Sulphate (ZTS) were grown from aqueous solutions by slow evaporation technique. The grown crystals have been subjected to single crystal X-ray diffraction to determine the unit cell dimensions. The grown crystals were also characterized by recording the powder X-ray diffraction patterns and by identifying the diffracting planes. The Fourier Transform Infrared (FT-IR) spectra have been recorded in the range 400–4500 cm −1. Second harmonic generation (SHG) for the materials of this work was confirmed using Nd:YAG laser. The UV–visible spectra show that the grown crystals have wide optical transparency in the entire visible region. The Thermogravimetric/Differential Thermal Analyses (TG/DTA) thermograms reveal that the materials have good thermal stability. Atomic absorption study reveals the presence of potassium in the doped f crystals. The electrical measurements were made in the temperature range 40–130 °C along c-direction of the grown crystals. The dielectric studies show that there may be a ferroelectric transition at 50 °C for both pure and KI-doped ZTS crystals. DC conductivity for both the samples is found to be increasing with increase in temperature. Activation energy values were also determined for both AC and DC conduction processes in the samples.

Growth and Studies of Pure and Lithium Bromide-Doped Zinc Tris-Thiourea Sulphate (ZTS) Single Crystals

Single crystals of pure and lithium bromide-doped Zinc Tris-thiourea Sulphate (ZTS) were grown from aqueous solutions by slow evaporation technique. The grown crystals were subjected to various studies such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), atomic absorption, and Second Harmonic Generation (SHG) studies. The density, melting point, DC conductivity, AC conductivity, dielectric constant, and activation energy of the grown crystals were also measured. The various studies revealed the incorporation of the impurity (lithium bromide) into ZTS crystals, and the investigations indicated that the impurity played an important role in the changes of the spectral and structural properties of ZTS crystals.

Growth and characterization of pure and potassium chloride-doped Zinc Tris–thiourea Sulphate (ZTS) single crystals

Single crystals of pure and potassium chloride-doped Zinc Tris–thiourea Sulphate (ZTS) were grown from aqueous solution by slow evaporation technique. The grown crystals were subjected to various studies such as XRD, FTIR, atomic absorption, SHG and TGA–DTA studies. The melting point and density of the grown crystals were also measured. The various studies revealed the incorporation of the impurity (potassium chloride) into ZTS crystals and the investigations indicated that the impurity played an important role in the changes of the spectral and structured properties of ZTS crystals.