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.     

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.     

Influence of Metallic Substitutions on the Optical and Mechanical Properties of NLO Benzoyl Glycine Crystals

Benzoyl glycine （BG） is a promising organic nonlinear optical （NLO） crystal, whose second harmonic generation （SHG） efficiency is much higher than that of KDP （potassium dihydrogen phosphate）. Single crystals of pure, Cu2＋ and Cd2＋ doped BG were grown by slow evaporation technique. Optically transparent and defect free single crystals of size up to 10 mm×15 mm×10 mm were harvested in a period of 40-60 days. The growth conditions of pure and doped crystals of BG were optimized and the grown crystals were confirmed by single crystal XRD （X-ray diffraction）. The grown crystals were characterized by FTIR （Fourier transform infrared spectroscopy）, optical absorption and microhardness studies. The microhardness studies confirm that BG has a moderate VHN （Vickers hardness number） value in comparison to the.other organic NLO crystals. The efficiency of frequency doubling was measured for the using Nd：YAG laser and the results were discussed.     

赖氨酸改性聚乳酸/聚乙二醇共聚物的制备及表征

在丙交酯与聚乙二醇开环共聚的基础上进行了二次聚合,利用具有生物相容性的赖氨酸对聚乳酸/聚乙二醇低聚物进行改性,制备出了赖氨酸改性聚乳酸/聚乙二醇共聚物。通过红外光谱、核磁共振谱、X射线衍射分析仪、差示扫描量热仪、凝胶渗透色谱和接触角测量仪分析比较了聚乳酸、聚乳酸/聚乙二醇和赖氨酸改性聚乳酸/聚乙二醇3种聚合物之间存在的差异。结果表明,实验成功合成了赖氨酸改性聚乳酸/聚乙二醇共聚物;赖氨酸(L-lys)的引入使得共聚物的热焓(ΔH)和熔点(T_m)分别由纯PLLA的81.57 J/g和177.34℃降到46.02 J/g和151.34℃,有效地改善了分子链的柔性和结晶度;聚合物的数均相对分子质量(M_n)也由纯PLLA的7.7×10~4降到了3.2×10~4,且相对分子质量分布变宽,但亲水性却得到大幅提高,有望适用于组织工程领域。     

Growth and properties of benzil doped benzimidazole (BMZ) single crystals

In the present work, we have made an attempt to study the effect of benzil doping on the properties of benzimidazole single crystals. For this purpose we have grown pure and benzil doped benzimidazole single crystals by vertical Bridgman technique. The grown crystals were characterized by various characterization techniques. The presence of dopants confirmed by powder X-ray diffraction (XRD). Crystalline perfection of the grown crystals has been analysed by high-resolution X-ray diffraction (HRXRD). The transmittance, electrical property and mechanical strength have been analysed using UV-vis-NIR spectroscopic, dielectric and Vicker's hardness studies. The relative second harmonic generation efficiency of pure and doped benzimidazole crystals measured using Kurtz powder test.     

Band gap enhancement on metal chelation: Growth and characterization of cobalt chelated glycine single crystals for optoelectronic applications

Single crystals of Diaqua Bisglycine Cobaltous Chloride (DBGCoCl) have been synthesized and grown by slow evaporation method. Grown crystals were subjected to FTIR and XRD studies for structural confirmation. The DBGCoCl crystallizes in the monoclinic system with the space group P2₁/c. The UV–vis spectrum for the pure glycine as well the cobalt chelated glycine have been recorded. The lower cutoff wavelength observed from the UV–vis spectrum is found to decrease by the chelation of cobalt with glycine and this leads to an increase in the band gap of the compound from 3.13 eV to 4.91 eV. The optical constants were calculated and illustrated graphically. Mechanical hardness of the grown crystal DBGCoCl was studied and Vickers hardness number was calculated. The work hardening coefficient (n) was determined to be 1.365 and the stiffness constants for different loads were calculated and reported. The thermal stability of the grown crystal has been studied using TGA and DTA. The crystal is thermally stable up to 116.86 °C.     

Studies on growth and characterization of an NLO crystal: L-alanine hydrogen chloride (LAHC)

A nonlinear optical (NLO) salt viz. L-alanine hydrogen chloride (LAHC) has been synthesized and solubility of the synthesized salt in de-ionized water was determined at different temperatures. Single crystals of L-alanine hydrogen chloride (LAHC) salt were grown by solution method with slow evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction (XRD) and powder XRD analyses to study the crystal structure. The crystallinity of LAHC crystal was confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. FTIR study was used to confirm the presence of various functional groups in the grown crystals. UV–visible transmittance spectrum was recorded to study the optical transparency of LAHC crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz–Perry powder test. The density of LAHC crystal was determined by floatation method. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to TG/DTA analyses. The dielectric behavior of the sample was also studied.     

Effect of l-alanine,Mn(II) and glycine dopants on the structural,crystalline perfection,second harmonic generation (SHG), dielectric and mechanical properties of BTCA single crystals

Bis thiourea cadmium acetate (BTCA) single crystals were grown at room temperature with different dopants by aqueous solution technique. The crystal system of the grown crystals with all the dopants was confirmed by powder X-ray diffraction study which confirms that there is no extra phase due to doping of l-alanine (LA), Mn(II) and glycine (Gly). It was further confirmed by FT-IR as well as FT–Raman spectroscopy analysis. The effect of LA, Mn(II) and Gly doping on the crystalline perfection was assessed by high-resolution X-ray diffractometry (HRXRD) analysis which revealed that the grown crystals with Gly doping are more perfect in comparison of other dopants. The SHG efficiency was measured using the Kurtz powder technique and shows that the grown crystals with Gly doping are more efficient in comparison of other dopants which is in tune with crystalline perfection. The low values of dielectric constant and loss also revealed that the grown crystals are defect free. The hardness values were found to be increased by increasing the doping concentration.     

Optical, structural and microhardness properties of KDP crystals grown from urea-doped solutions

Potassium dihydrophosphate single crystals were grown from aqueous solutions onto a point seed using temperature reduction method by doping with different molar values of urea. The characterization of the grown crystals was made by visible and Fourier transform infrared spectroscopy, Vicker's hardness studies, X-ray powder diffraction, non-linear optical and laser damage threshold measurements. By comparing these crystals with the ones grown from the pure solution, it is shown that 0.2-2.0 M of the urea additive enhances the laser damage threshold and the second harmonic efficiency more than by 25 and 20%, respectively. By means of the Bond method using a multipurpose three-crystal X-ray diffractometer it is shown that the presence of urea additive increases the crystal lattice parameter c of the grown crystals, whereas the lattice parameter a is by an order less sensitive to the changing urea concentration in the solution. The Vicker's hardness studies at room temperature carried out on (1 0 0) and (0 0 1) crystallographic planes show an increased hardness of the doped crystals (grown in the presence of urea additive) on the plane (0 0 1) in comparison with that of pure potassium dihydrophosphate crystal.     

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.     

Study of pure and l-tartaric acid doped ammonium dihydrogen phosphate single crystals: A novel nonlinear optical non-centrosymmetric crystal

Single crystals of pure and l-tartaric acid (LTA) C₄H₆O₆ doped ammonium dihydrogen phosphate (ADP) (NH₄) H₂PO₄ were grown by slow evaporation solution technique (SEST) at ambient conditions. Powder X-ray diffraction (PXRD) analysis was carried out to confirm the crystal structure and no additional phase was observed due to doping except a systematic variation in peak intensities. Fourier transform infrared spectral analysis was done to examine the presence of various functional groups in the grown crystals. UV–VIS–NIR spectroscopic analysis was carried out to see the change in optical transparency of pure ADP and crystals due to LTA with different doping concentrations. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystals. The effect of LTA dopant on crystal morphology, thermal and mechanical properties of ADP have also been presented in this paper. The above studies reveal the effect of incorporation of LTA into the lattice of ADP crystals.     

Hybrid coatings of poly(L-lysine) and apatite on micro-arc oxidized titania

Hybrid coatings of poly(L-lysine) and apatite were formed on the micro-arc oxidized titania through a biomimetic process. Phosphorous (P)-containing titania films were prepared by micro-arc oxidation (MAO) of titanium (Ti) substrates in an electrolyte solution containing β-glycerol phosphate disodium salt pentahydrate. The hybrid coatings were grown by immersing MAO titania in the poly(L-lysine)-containing simulated body fluid (SBF) solution. After 72 h immersion, the globular precipitates appeared on the surface of titania films and grew up to ~ 10 µm. These precipitates consisted of 100–200 nm nano-flakes with a distorted (less straight) morphology. XRD and FT-IR confirmed that these precipitates were poly(L-lysine)-containing apatite nanocomposite.     

Growth and characterization of glycinium oxalate (GOX) single crystals

Glycinium oxalate (GOX) single crystals were grown by slow cooling solution growth method. The X-ray diffraction and Fourier transform infra red studies confirm the grown crystal. The hardness values of GOX are found to be higher than glycine. The increase in hardness may be due to the C-H---O bonding. The UV-Visible studies show that GOX crystals can be used for nonlinear applications. The dielectric measurement indicates that the GOX crystals have domains of varying sizes and varying relaxation time. The SHG output of GOX was 210 mV at given pulse energy of 5 mJ/s and KDP was 240 mV.     

Growth of TGS single crystal by conventional and SR method and its analysis on the basis of mechanical, thermal, optical and etching studies

Unidirectional <001> bulk ferroelectric Tri glycine sulphate (TGS) single crystal of diameter 18 mm and length 150 mm was successfully grown by SR method. The grown TGS single crystal was characterized using etching, Vicker's microhardness, TG-DTA and UV-Vis analysis. The TGS crystals grown by SR method have higher hardness than conventional method grown crystals. Dislocation density (DD) is less in SR grown crystal compared to conventional method grown TGS crystals. The transmittance of SR grown TGS is 8% higher than that of the conventional grown crystal.     

Growth and characterization of nonlinear optical diglycinehydrobromide single crystals

Diglycinehydrobromide (DGHB) a semi-organic nonlinear optical material with the molecular formula C₄H₁₁N₂O₄⁺Br⁻ has been synthesized at ambient temperature. Chemical composition of the synthesized material was confirmed by CHN analysis. Functional groups present in the sample were identified by FT-IR and Raman spectral analysis. Bulk single crystals of DGHB were grown by slow evaporation method at constant temperature. Powder X-ray diffraction pattern of the grown DGHB has been indexed. Unit cell parameters of the grown DGHB crystals were determined. Thermal stability of DGHB was determined from TGA/DTA and DSC response curves. Mechanical hardness of the grown crystal DGHB was determined and Vickers hardness number was calculated. The optical transparency and the lower cutoff of UV transmission were identified from the recorded UV-vis-IR spectrum of DGHB. The Kurtz powder second harmonic generation test shows that the crystal is a potential candidate for optical second harmonic generation.     

Optical, structural and electrical properties of pure and urea doped KDP crystals

Single crystals of good optical quality, made of potassium dihydrogen phosphate (KDP) doped with urea were grown by slow evaporation solution growth technique at a constant temperature of 35 °C. Optical absorption and dielectric properties were studied for pure and urea doped KDP crystals. Using powder XRD studies, crystalline nature of pure and urea doped KDP crystals was confirmed. AC conductivity was measured for the grown crystals. DC electrical conductivity and photoconductivity studies were carried out for pure and urea doped KDP crystals and the differences caused by the dopant were also discussed.     

Growth, structural, optical, thermal and mechanical properties of glycine zinc chloride single crystal

The nonlinear optical single crystals of glycine zinc chloride were grown by the slow cooling method from aqueous solution. The title compound was synthesized and purified by repeated recrystallization process. Grown crystals were characterized by X-ray diffraction, FT-IR and FT-Raman spectral analysis. The range and percentage of optical transmission were ascertained by recording UV-Vis-NIR spectrum. Thermal properties were investigated by DTA and TGA analyses. Its second harmonic generation relative efficiency was measured by Kurtz and Perry powder technique using Nd:YAG laser and was observed to be 0.5 times that of potassium dihydrogen orthophosphate. Its mechanical hardness was estimated by Vickers microhardness method.     

Unidirectional growth of <101>glycine zinc chloride single crystal by Sankaranarayanan-Ramasamy method

Single crystals of glycine zinc chloride (GZC), a semi-organic compound, were grown by conventional as well as unidirectional Sankaranarayanan-Ramasamy (SR) methods. Transparent GZC crystal of diameter 15 mm and length 50 mm was obtained by employing SR growth method. The average growth rate along <101> is 0.32 mm/day and 1.25 mm/day for crystals grown by conventional and SR methods. The crystals grown by conventional and SR methods were analyzed using chemical etching, UV-Vis and Vickers microhardness. The results show that SR method grown crystals exhibit higher transmittance and hardness possessing less dislocation density as against crystals grown by conventional method.     

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.     

Synthesis and characterization of pure,urea and thiourea doped organic NLO l-arginine trifluoroacetate single crystals

Optically transparent l-arginine trifluoroacetate (LATF) single crystals by doping with organic materials urea and thiourea were grown by slow solvent evaporation technique. Powder X-ray diffraction confirms improvement in the crystalline quality for urea doped crystals. Urea doping in LATF also improves the percentage of transmittance. The vibrational frequencies of the grown crystals were assigned by Fourier Transform infrared spectroscopy. The thermal analysis (TG/DTA) indicated the better thermal stability for urea doped LATF crystals. EDAX analysis was carried out to calculate the percentage of elements present in doped and pure LATF. The hardness has been remarkably improved on urea and thiourea doped LATF crystals. The second harmonic generation (SHG) analysis showed 2.5 times than standard KDP for pure LATF and 2.2, 2.07 times than KDP for urea and thiourea doped LATF.