Enhanced optoelectronic,thermal, mechanical and third order nonlinear optical properties of dichlorobis(thiourea)zinc(II) crystal: an effect of Phenol red dye

For the first time the growth of dichlorobis (thiourea) zinc(II) (ZTC) monocrystal in presence of Phenol red dye of considerably good size (~13 mm?×?5 mm) has been achieved from aqueous solution using slow evaporation solution technique at room temperature. The solubility was calculated at different temperatures. The crystal structure was confirmed through X-ray diffraction analysis. The crystallinity of the dyed crystals has been enhanced revealed by Powder X-ray diffraction study. The presence of dye was inveterate by FT-IR and FT-Raman spectroscopic studies. The scanning electron microscopy analyses show that the grown crystals with dye are better than pure. Diffused reflectance was measured and optical band gap was calculated found to be enhanced from 4.5 to 4.65 eV for dyed crystals. The enhancement in the PL intensity has been observed in the dyed crystals. DSC study shows that the thermal stability has been remarkably enhanced from 163?°C (pure) to 203?°C (dyed) and various other thermal parameters are calculated. The surface study shows that the grown crystals with dye possess less dislocation than pure. Mechanical strength of the dyed crystal is found to be remarkably enhanced. Third-order nonlinear optical susceptibility (χ3) of PRZTC was found to be 2 times higher than pure. All results suggest that the properties of ZTC crystals grown in presence of dye are enhanced and can be considered as better contender in various nonlinear devices.     

Growth and properties of manganese and lithium doped TGS crystals

Mn⁺² doped and Li⁺ doped TGS crystals (MTGS and LTGS) have been grown from the TGS solution containing MnSO₄·H₂O and Li₂SO₄·H₂O respectively by the slow cooling method. The growth habit and domains configuration of MTGS and LTGS are altered from those of TGS crystal. The dielectric properties of both crystals are of the same order to that of TGS, but the pyroelectric coefficients are much higher than that of TGS. An internal chemical bias field has been observed in LTGS and MTGS crystals.     

TGS和GTGS热释电晶体的热力学模型模拟曲线

通过热力学推导,建立了零电场下热释电晶体的极化与温度的方程。由热释电系数的定义,对热释电晶体的极化方程对温度求导,得出由热力学模型建立的热释电方程。并对热释电晶体硫酸三甘氨酸（TGS）和掺胍TGS（GLTGS）的实验曲线进行了模拟,该理论基本符合。     

Morphological changes of L-asparagine doped TGS crystal

This paper discusses the growth and properties of Triglycine Sulphate Crystals (TGS) and with L-Asparagine. Doped single crystal was grown by slow-cooling solution growth technique. TGS crystals with 10 wt% of L-Asparagine exhibited prominent morphological changes in the (101) and (001) planes. Lattice parameter values were determined by powder X-ray diffraction analysis. Incorporation of L-Asparagine in TGS crystals has been qualitatively estimated and confirmed by Fourier Transform Infrared (FTIR) spectra. Micro hardness studies also performed for the pure and doped crystals. A morphology diagram is given.     

Thermal-Diffusivity Dependence on Temperature of Gadolinium Calcium Oxoborate Single Crystals

Thermal diffusivities of pure and doped gadolinium calcium oxoborate (GdCOB) single crystals were measured as a function of the temperature along optical indicatrix axes X, Y, and Z. Three GdCOB samples were investigated, chemically pure single crystal, the one doped with 4 at% of Nd and the next one doped with 7 at% of Yb. Measurements were carried out for temperature range 40 °C to 300 °C. Determination of the thermal diffusivity based on an analysis of thermal wave propagation in the sample. For a detection of temperature disturbance propagating in the sample the mirage effect was used. Obtained results show that the thermal diffusivity decreases with the increase of sample temperature for all investigated crystals. The GdCOB single crystals reveal a strong anisotropy. The thermal diffusivity along Y direction has the highest value while values obtained in X and Z axes are much lower. Dopants cause decrease in the thermal diffusivity for all investigated directions.     

Modified triglycine sulphate (TGS) single crystals for pyroelectric infrared detector applications

Effect of caesium and cerium,l-alanine and caesium +l-alanine impurities are investigated on ferroelectric and pyroelectric properties of TGS crystals. Dielectric constant and loss, pyroelectric coefficient, spontaneous polarization and coercive field measurements of these modified crystals, as a function of temperature are reported. Caesium and cerium did not affect the electrical properties of TGS crystals significantly, whereasl-alanine- and, especially, Cs +l-alanine-doped TGS crystals exhibited promising improvements in pyroelectric properties, up to 48 °C, as compared to pure TGS crystals.     

Effect of cobalt (Co<Superscript>2+</Superscript>) concentration on structural,optical, thermal and mechanical properties of potassium acid phthalate (KAP) crystals

Single crystals of pure and Co²⁺ (0.2, 0.4 and 0.6 mol%) doped KAP crystals were grown by low temperature slow evaporation method. The grown crystals were subjected to various characterization techniques such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV–visible spectroscopy and Second Harmonic Generation studies. The XRD profile confirms that Co²⁺ ions incorporated into the KAP crystal lattice. The existence of functional groups in the grown crystals have been studied by FTIR analysis. Optical transmission is decreased when doping Co²⁺ concentration increase. After melting point, no decomposition is found in the pure crystal. Vickers micro hardness studies revealed that the doped crystals possess very high hardness values. The dielectric constant, dielectric loss and thermal stability values have been measured as a function of frequency and temperature respectively for the doped crystals.     

Optimization of CdO nanoparticles by Zr<Superscript>4+</Superscript> doping for better photocatalytic activity

Chemically controlled co-precipitation method has been adopted for the fabrication of pure and different wt% Zr doped CdO photocatalysts. Conventionally, the crystallite size and crystalline phase of CdO are in the midst of the parameters involved in the control of the photocatalytic activity. Aiming utterly at the size effect that modifies other attributes which are important to assess the photocatalytic activity of nanometric CdO, it was explored to synthesize CdO nanoparticles with controlled size, highly comparable morphology and analogous phase. The crystal structure and the crystallite size were estimated from the X-ray diffraction patterns and were confirmed through transmission electron microscope. The degree of crystallinity varied on Zr doping and the calculated crystallite sizes were in the range of 16–81 nm. The dopant ion Zr⁴⁺ have been detected through X-ray photoelectron spectroscopy (XPS) analysis signifying the dopant to substitute for cadmium (Cd²⁺) in the lattice of CdO. Particle size dependent optical band gaps calculated in the range 2.02–2.57 eV informed the viability of the materials to initiate photocatalytic reaction in the visible light region. Lesser recombination rate of the generated electrons and holes under light irradiation produced low intense photoluminescence peaks that displayed the appropriateness as photocatalysts. Zr⁴⁺ doping resulted in the enhancement of photocatalytic activity, evaluated by monitoring the degradation of methylene blue solution. 0.5 wt% Zr doped CdO nanoarticles calcined at 400 °C exhibited the highest photocatalytic activity with better percentage of color abatement (80.95%). The pseudo-first-order reaction rate became faster on Zr doping such that the rate constant is ~?0.4–0.5 h^?1 for Zr doped CdO while that for pure CdO is ~?0.3 h^?1.     

A multisource energy harvesting utilizing highly efficient ferroelectric PMN-PT single crystal

This paper demonstrates a multi-source energy harvester that is able to utilize simultaneously both piezoelectric and pyroelectric effects in lead magnesium niobate-lead titanate (PMN-PT) single crystal. The paper presents a study of PMN-PT single crystal with a (67:33) composition grown in our laboratory via a vertical gradient freeze method without any flux. The performance of the piezoelectric and pyroelectric energy harvester using unimorph device structure was evaluated via modeling and experiment. The theoretical study was implemented based on a distributed parameter electromechanical model and the modelling procedure was approximated using finite element analysis to predict the electromechanical behavior of the harvester. The maximum power density at a resonance frequency of 50 Hz and optimum resistance of 2 MΩ was 16.7 nW/(g² cm³) under a 1 g acceleration of vibration. The measured values of electrical output parameters were in good agreement with theoretical and modelling results using MATLAB and COMSOL Multiphysics, respectively. By using the pyroelectric effect along with the piezoelectric effect, the output voltage of the energy harvester was found to be enhanced at the optimum resistance and specific frequency values. It was noticed that the output voltage was increased monotonically with temperature-difference (ΔT) and reaches up to 180 % of its original value under temperature difference of 1.7 °C at a frequency value of 49 Hz.     

Thermal properties of Pure and Doped TGS,DTGS, TGFB and DTGFB single crystals

The thermal properties of pure and doped single crystals of TGS type materials were determined over the temperature range 20 to 90°C. Measurements of the thermal conductivity were made along the principal crystallographic axes and were found to be independent of temperature. Impurity incorporation generally decreased the thermal conductivity with Zn doping exhibiting the largest effect. The thermal diffusivity of these materials was calculated from measurements of thermal conductivity, specific heat and density.     

Growth and characterization of pure and cadmium dichloride doped aminoethanoic acid (AEA) single crystals

Organic and semiorganic centrosymmetry single crystals of pure and cadmium dichloride doped aminoethanoic acid was successfully grown by slow evaporation solution growth technique. The solubility of the grown crystals was studied for different temperatures upto 50 °C. The single crystal X-ray diffraction analysis shows that the grown crystal belongs to monoclinic system and their unit cell parameter values were determined. The presence of various functional groups was identified by Fourier transform infrared spectroscopy. UV–Vis spectrum shows a wide optical transmittance in the visible region and the obtained lower cut off wavelength is around 252 nm. The presence of 0.31 mg of cadmium element per litre of water was measured by AAS analysis which indicates the effect of dopant in the material. TG/DTA study reveals that the organic complex has slightly more stable than the semiorganic complex and it has high thermal stability of about 193 °C. Vickers microhardness tester confirms the reverse indentation size effect of the crystals and found that the crystals belongs to soft material category by Meyer law. Dielectric study was carried out on the grown crystals which represent the lower value of dielectric constant while increase the frequency.     

Structural,optical and magnetic properties of Ba and Ni doped CdS thin films prepared by spray pyrolysis method

Pure, Barium and Nickel doped cadmium sulphide (CdS) thin films have been coated on glass substrates at 400?°C by spray pyrolysis technique. The prepared CdS and doped CdS thin films were analysed by various measurements such as X-ray diffraction (XRD), SEM, optical and Vibrating Sample Magnetometer (VSM). X-ray diffraction measurements show that the coated pure, Ba and Ni-doped CdS thin films belong to the cubic crystal structure with orientation preferentially along (111) direction. The average crystallite size of pure, Ba and Ni doped CdS thin films were determined as 31, 33 and 45 nm, respectively. The average dislocation density (δ) and stacking fault (SF) of pure, Ba and Ni doped CdS thin films were also determined. The surface morphology and elemental analysis of the thin films were determined by scanning electron microscopy and energy dispersive X-ray spectrum (SEM with EDAX). It is observed that the optical energy bandgap has been decreased from 2.43 to 2.1 eV due to the doping Ba. The luminescence spectrum shows a strong emission peak at 517 nm in the case of pure CdS thin film and a meager red shift has been observed due to the doping. VSM studies were employed to study the magnetic behaviour of Ba and Ni doped CdS thin films.     

Microhardness,FTIR and transmission spectral studies of Mg2+ and Zn2+ doped nonlinear optical BTCC single crystals

Pure, Mg²⁺ and Zn²⁺ doped BTCC single crystals are grown from their aqueous solutions at 301 K. The grown crystals are characterized by single crystal XRD, FTIR and UV–Vis-NIR spectral studies. The preliminary investigations of the UV–Vis-NIR spectra on the doped samples suggest an increased percentage of transmission in comparison to pure BTCC crystals. The SHG efficiency of the metal doped BTCC crystals is found better than the pure ones. It is estimated from the microhardness studies that the mechanical strength of the BTCC crystals are improved due to the metallic (Mg²⁺ and Zn²⁺) substitutions.     

Infrared spectroscopic characterization of Na5Lu9F32 single crystals doped with various Er3+ concentrations

This work reports on optical spectra of Na₅Lu₉F₃₂ single crystals doped with various Er³⁺ concentrations from 0.5 to 5 mol%. In our improved Bridgman method, the X-ray powder diffractions were investigated and optical parameters were also calculated by the Judd–Ofelt theory. Results showed that Er³⁺ ions entered the Lu³⁺ sites successfully without causing any obvious peak changes, and the doping concentration of Er³⁺ had important influence on the Er³⁺ local structure in Na₅Lu₉F₃₂ crystals. The maximum emission intensities of ~1.5 and ~2.7 μm were obtained in present research when the doping concentration of Er³⁺ were 4 and 5 mol%, respectively, under the excitation of 980 nm LD. In these doping concentration, the maximum emission cross-sections were calculated to be 1.37 × 10^?20 cm² (~1.5 μm) and 2.1 × 10^?20 cm² (~2.7 μm). The gain cross-section at 2.7 μm was also estimated according to the absorption and emission cross section spectra. All these spectroscopic characterizations suggested that this fluoride crystal would possess promising applications in infrared lasers.     

Annealing effect on structural, optical and electrical properties of pure and Mg doped tin oxide thin films

This study describes the effect of annealing at different temperatures (400–600 °C) on structural, optical and electrical behaviors of pure and Mg doped tin oxide thin films grown on the glass substrate by electron beam evaporation technique. The transformation of tetragonal to orthorhombic form due to annealing, introduced a change in the optical and electrical properties of pure and Mg doped tin oxide thin films. X-ray diffraction studies or analysis revealed the phase transformation and change in the crystalline size with increase in the annealing temperature. The morphology and roughness of the thin films were studied by Atomic force microscopy. Optical band gap increased with annealing temperature confirms the improvements of crystallinity. The quality of thin films transparency was investigated by UV/Vis-spectroscopy. Photoluminescence of pure and Mg doped tin oxide thin films shows two extra peaks one at 486 nm and other at 538 nm is due to the crystal defect created as a result of annealing temperature. These peaks became stronger and shifted to longer wavelength with increasing the annealing temperature. The complex plot (Nyquist plot) showed the data point laying on two semicircles and the resistance of grains and grain boundaries increases with the increase in annealing temperature for both pure and Mg doped tin oxide thin films.     

Properties of triglycine sulfate/poly(vinylidene fluoride-trifluoroethylene) 0-3 composites

Composites of triglycine sulfate (TGS) powder dispersed in a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE), 70/30 mol%) copolymer matrix have been prepared using solvent casting followed by compression moulding. The composites have been characterized by means of scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Three groups of samples have been prepared: unpoled composites, composites with only the TGS phase poled and composites with both phases poled. The observed relative permittivity of these composites are consistent with the predictions of the Bruggeman model. When the TGS and copolymer phases are poled in the same direction, the piezoelectric activities of the two phases partially cancel each other while the pyroelectric activities reinforce. The pyroelectric coefficients exhibit good agreement with the effective-medium model. These composites have high pyroelectric figures of merit which increase as the volume fraction of TGS increases.     

Influence of NH4Cl on the < 1 0 0> directed growth and properties of ADP crystal

Good quality, pure and ammonium chloride added < 1 0 0> directed ADP single crystals with different sizes were grown by Sankaranarayanan-Ramasamy method with the vision to improve the properties of the crystal. The grown crystals have cylindrical morphology and the crystals were subjected to UV-Vis., DTA, microhardness, laser damage threshold, dielectric, piezoelectric and SHG studies. The addition of ammonium chloride improves the quality and yields crystals with transparency more than 80% in minimum duration of growth. Higher laser damage threshold and mechanical stability were observed in ammonium chloride added ADP crystals. Low dielectric loss shows that the grown crystal contains minimum defects. Good piezoelectric behaviour was observed for the grown crystals. The SHG efficiency of the crystals was obtained using Nd-YAG laser, which is approximately 3 times that of pure ADP and shows the suitability of the ingot for nonlinear optical applications.     

Growth and characterization of metal ions and dyes doped KDP single crystals for laser applications

The organic dyes (Amaranth, Rhodamine B and Methyl Orange) are doped in Potassium Dihydrogen Phosphate crystals. Influences of supersaturation and dye concentration in the solution, on the color and crystal habit of Potassium Dihydrogen Phosphate, were observed. Amaranth in the solution at low super saturation and high dye concentration colored the pyramidal section (1 0 1) of the crystals. The highly super saturated solutions produce entirely colored crystals. Dyes doped Potassium Dihydrogen Phosphate crystals were also grown by solution growth technique. The concentration of dopants in the mother solution was varied from 0.1 to 10 mol%. The studies on pure and doped Potassium Dihydrogen Phosphate crystals clearly indicate the effect of dopants on the crystal structure, in the absorption of IR frequencies and the non-linear optical property. The frequencies with their relative intensities are obtained in Fourier Transform-Infrared spectra of pure and doped Potassium Dihydrogen Phosphate. The very weak bands for dopants indicate its presence in low concentration. The absence of even such a weak band in the case of Potassium Dihydrogen Phosphate doped with Amaranth indicates the strong interaction with O-H groups. The calculated IR frequency 3333 cm⁻¹ for O-H stretching was in close agreement with the experimentally obtained one for pure Potassium Dihydrogen Phosphate at 3340 cm⁻¹.The doped crystals show good second harmonic generation efficiency. The dopants increase the hardness value of the material, which also depends on the concentration of the dopants. Dye doping improves the Nonlinear Optical properties of the grown crystals. Results of the growth kinetics of Potassium Dihydrogen Phosphate crystals in the presence of impurities are also discussed.     

Doping effect of urea on growth,spectral, thermal,mechanical, electrical,nonlinear and optical studies of Sr(HCOO)<Subscript>2</Subscript>·2H<Subscript>2</Subscript>O crystal: enhanced third-order NLO properties with a high laser-induced damage threshold

Pure and urea doped (with 3 different concentrations, viz. 0.005, 0.05, and 0.1 M) strontium formate dihydrate (SFD, Sr(HCOO)₂·2H₂O) single crystals were grown from aqueous solutions by using slow solvent evaporation technique. In order to understand the effect of urea doping on the structural, chemical, thermal, morphological, optical properties of SFD crystals, the grown crystals were characterized by carrying out CHN analysis, powder X-ray diffraction, high resolution X-ray diffraction, Fourier transform infrared spectral, thermogravimetric, UV–Vis–NIR spectral, photoluminescence spectral, second harmonic generation efficiency, and Z-scan measurements. The results obtained indicate that the urea molecule have entered into the SFD crystal matrix and has improved the crystallinity. Also, the results indicate that urea doping significantly tunes the optical and thermal properties without significantly distorting the crystal structure of SFD crystal. The laser damage threshold (LDT) energy for the grown crystal has been measured by using a Q-switched Nd:YAG laser as a source in single-shot mode (1064 nm, 10 Hz, 420 mJ). The result of laser damage threshold (LDT) energy indicates that grown title crystal has excellent resistance to laser radiation than those of some known inorganic NLO materials. Its third-order nonlinear optical properties were investigated by Z-scan technique and proved that the grown crystal possesses two-photon absorptions (TPA) and the self-defocusing effect.     

Impact of nickel doping on structural,optical, electrical,and third-order NLO behavior of piperazinium L-tartrate single crystals

Slow evaporation technique was used to grow single crystals of pure and nickel (Ni)-doped piperazinium L-tartrate (PPLT). Powder crystal X-ray diffraction was used to characterize the structural properties of the grown crystals. Fourier transform infrared spectroscopy was used to determine the functional groups. In the visible band, both pure and Ni-doped PPLT crystals have low absorbance, indicating their utility in nonlinear optical (NLO) applications. PPLT crystals, both pure and Ni doped, have bandgap energies that indicate their insulating nature, indicating their utility in electronic applications. The growth pattern and dislocation density of the crystal are revealed by etching analysis. The electric field response of generated single crystals was investigated in terms of dielectric constant and dielectric loss as a function of the frequency and temperature, with the findings described. The efficiency of nickel-doped PPLT crystal is 2.86 times larger than potassium dihydrogen phosphate (KDP), whereas the efficiency of pure PPLT is 1.38 times greater than KDP, according to NLO testing measured by Kurtz powder method. Because metal ions were incorporated into the crystal lattice, the SHG efficiency of nickel-doped PPLT was somewhat improved.