Growth and characterization of unidirectional (100) KDP single crystal by Sankaranarayanan-Ramasamy (SR) method

Unidirectional (100) potassium dihydrogen orthophosphate (KDP) single crystals were grown by Sankaranarayanan-Ramasamy (SR) method. The (100) oriented seed crystals were mounted at the bottom of the glass ampoules and the crystals of 20mm diameter, 30 mm height and 15 mm diameter, 65 mm height were grown by SR method. The grown crystals were characterized by high-resolution X-ray diffractometry anlaysis, UV-vis spectroscopy, dielectric and microhardness studies. The high-resolution X-ray diffractometry anlaysis indicates that the crystalline perfection is excellent without having any very low angle internal structural grain boundaries. The SR method-grown unidirectional KDP has 15% higher transmittance compared to conventional method-grown crystals. The dielectric constant was higher and the dielectric loss was less in SR method-grown crystal. The crystals grown by SR method have much higher hardness value than conventional method-grown crystals. The quality of the crystal grown by SR method is better than conventional method-grown crystal.     

Effect of sunset yellow dye on morphological,optical, dielectric,thermal and mechanical properties of KDP crystal

Herein, we describe the growth and morphology of well-defined dyed crystals of KH₂PO₄ (potassium dihydrogen orthophosphate; KDP) containing organic azo (sunset yellow; SSY) dye in the {1 0 1} & {0 0 1} pyramidal growth sectors. An understanding on selective dye inclusion in various growth sector of host crystal is proposed, which will help in designing novel tailor-made dyed photonic crystals. The structural analysis and the identification of various functional groups present in as grown KDP crystals were carried out using powder XRD, FTIR and Raman studies. Solid state transmittance spectra for dyed KDP crystals displayed three absorption peaks at 230 nm, 311 nm and 477 nm, which were blue shifted for SSY dye in KDP crystal relative to neutral aqueous solution of SSY dye. These blue shifts in the absorption maxima confirm the successful incorporation of sunset yellow dye into the pyramidal growth sectors of dyed KDP crystals. The band around 409 nm in the photoluminescence emission spectrum indicates a violet emission. SSY dye doped KDP crystals showed enhanced dielectric properties and thermal stability as compared to pure KDP crystal. The mechanical strength of the KDP crystals estimated using Vickers microhardness test was found to decrease with the increase in SSY dye doping.     

Growth and characterization of NLO based l-arginine maleate dihydrate single crystal

Single crystals of l-arginine maleate dihydrate (LAMD) were successfully grown from aqueous solution by solvent evaporation technique. As-grown crystals were analyzed by different instrumentation techniques such as X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectra and UV–vis near infrared (NIR) transmittance spectra. Thermal behavior has been studied with TGA/DTA analyses. The optical second harmonic generation (SHG) conversion efficiency of LAMD was determined using Kurtz powder technique and found to be 1.5 times that of KDP.     

Effect of complexing agent (1,10-phenanthroline) on ADP and KDP crystals

1,10-Phenanthroline (Phen) as a new additive was added into the solutions of KH₂PO₄ (KDP) and NH₄H₂PO₄ (ADP) in a small amount (∼2.5·10⁻³ M L⁻¹). The crystals were grown from the aqueous solutions of pH ∼4.5 at constant temperature by solvent evaporation technique. It leads to an increase in metastable zone width and assists the bulk growth process. The growth rate of crystals in the presence of Phen decreases considerably with an increase in impurity concentration (∼2.5·10⁻² M L⁻¹). Not much variation is observed in FTIR and XRD of pure and doped ADP/KDP. It appears that the growth promoting effect (GPE) of Phen is caused by the adsorption of the organic additive on the prism faces of ADP/KDP crystals. Higher optical transmittance is observed in the presence of the dopant. Detailed microhardness studies of ADP crystals reveal the anisotropy in the hardness behaviour. Scanning electron microscope (SEM) photographs exhibit the effectiveness of the impurity in changing the surface morphology of ADP/KDP crystals. Contrary to expectations, Phen depresses the NLO efficiency of ADP/KDP, suggesting that the molecular alignments in the presence of Phen results in cancellation effects disturbing the non-linearity.     

Study on parylene/SiO<Subscript>2</Subscript> composite films for protection of KDP crystals

In this paper, parylene/SiO₂ composite films were reported to protect KDP crystals, indispensable cells in ICF experiments, from moisture. FTIR, UV-NIR spectra and XPS were used to analyze the properties of films. Laser damage threshold of films was also measured. With porous silica coating on surface of parylene film, the transmittance of dual layers can be raised to more than 91%. KDP crystals with poly(p-xylylene)/SiO₂ coating could work well in ambient atmosphere for more than half a year.     

Influence of SiO_3~（2-）Impurity on the Optical Properties of KDP Crystal

In this paper,potassium dihydrogen phosphate(KDP) crystals were grown in the presence of a series of silicate(SiO32-) impurity concentrations via conventional temperature cooling and rapid growth methods,respectively.It revealed that the SiO32-impurity could lead to the decrease of transmittance at the region of ultraviolet band for pyramidal sectors and slightly increased the transmittance for prismatic sectors.SiO32-could enter into the crystal lattice and create lattice defects,which consequently increased the density of light scatter.The decrease of laser damage threshold was attributed to the lattice defects and the redundant electrons brought by the replacement of SiO32-at the PO43-position.     

Growth, structural, spectral, mechanical, thermal and dielectric characterization of phosphoric acid admixtured L-alanine (PLA) single crystals

Phosphoric acid admixtured L-alanine (PLA) single crystals were grown successfully by solution method with slow evaporation technique at room temperature. Crystals of size 18 mm×12 mm×8 mm have been obtained in 28 days. The grown crystals were colorless and transparent. The solubility of the grown samples has been found out at various temperatures. The lattice parameters of the grown crystals were determined by X-ray diffraction technique. The reflection planes of the sample were confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. Fourier transform infrared (FTIR) studies were used to confirm the presence of various functional groups in the crystals. UV-visible transmittance spectrum was recorded to study the optical transparency of grown crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz-Perry powder technique and a study of its second harmonic generation efficiency in comparison with potassium dihydrogen phosphate (KDP) has been made. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to thermo gravimetric and differential thermal analysis (TG/DTA). The dielectric behavior of the sample was also studied.     

Semiorganic nonlinear optical material for frequency doubling: preparation and properties of sodium p-nitrophenolate dihydrate (SPNP)

Sodium p-nitrophenolate (SPNP), a semiorganic nonlinear optical (NLO) material useful for frequency doubling in the IR region, has been synthesized. The solubility studies have been carried out in the temperature range 30-50 degrees C. Single crystals (size 12 mmx7 mmx4 mm) have been grown by slow evaporation of the saturated aqueous solution (methanol as solvent) at 30 degrees C. The lattice parameters of the grown crystals have been determined by single crystal X-ray diffraction technique. The UV-vis-NIR transmittance spectrum has been recorded in the range 200-1500 nm. The molecular structure was confirmed by FT-IR and FT-NMR. SPNP was thermally stable up to 103 degrees C as determined by TG/DTA curves. By a modified Kurtz and Perry method, the powder SHG efficiency was found to be five times that of KDP and its phase matching property was established. Laser damage threshold of SPNP was determined using a Nd:YAG laser.     

Growth,geometrical analysis,FMO, MEP UV–vis,nonlinear optical and antibacterial properties of pure and 2-furoic acid doped Guanidinium carbonate single crystal

In the presence of distilled water, the adaption of the slow evaporation solution growth approach resulted in the successful development of single crystals of Pure and doped GC (FAGC). The cell characteristics of the produced FAGC crystals were investigated using single-crystal X-ray diffraction analysis. The theoretical analysis was carried out using the DFT method, and the HOMO-LUMO energy band difference was estimated. The Molecular optimized geometry, MEP and HOMO-LUMO energy distance were computed using the B3LYP level of theory using a 6-31G (d,p) basis set. The FT-IR spectrum probes the modes of vibration of various functional groups in pure and doped GC (FAGC) crystals. According to UV–visible NIR transmittance experiments, the formed crystal exhibits a high transmittance in the whole visible range. The relative SHG efficiency of pure and doped crystals (FAGC) was carried out by the Kurtz perry technique. The Antibacterial activity demonstrates that both the pure and the dopant have antibacterial action against dangerous microorganisms.     

Researches on the Growth Habit and Optical Properties of Fe^3＋ Ion Doped KDP Crystal

During the process of KDP crystal growth,metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper,KDP crystals were grown from an aqueous solution doped with different concentration of Fe3+ dopant by traditional temperature-reduction method and "point-seed" rapid growth method. Furthermore,we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe3+ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe3+ ion on the growth habit and optical properties of KDP crystal are also obvious.     

Study on the Growth and Quality of Potassium Dihydrogen Phosphate Grown from Acid-doped Solution

Potassium dihydrogen phosphate （KDP） single crystals have been grown respectively at the rates of about 1 and 20 mm/day from the pure and acid-added solutions by temperature reduction method. The effects of acid and supersaturation on the shape and size of grown crystals were compared and discussed. Samples were cut from different parts of the as-grown crystals for investigating the optical quality, including transmissibility, scattering centers and laser damage threshold. It is found that the stability of KDP growth solution improves to some extent and the growth rates in x- and z-directions have great difference after adding acid. Moreover, the acid causes remarkable differences in optical quality between prismatic and pyramidal sectors.     

Mechano- and Photoresponsive Behavior of a Bis(cyanostyryl)benzene Fluorophore

The mechanoresponsive behavior and photochemical response of a new bis(cyanostyryl)benzene fluorophore (CSB-5) were investigated. Green fluorescence with λ_em,max of 507 nm was found for CSB-5 in chloroform solution, mirroring the behavior of a previously reported similar dye (CSB-6). Alternatively, crystalline samples of CSB-5 exhibited orange fluorescence with λ_em,max of 620 nm, attributable to excimer emission. Although the emission color change was not clearly noticeable by naked eye, CSB-5 exhibited mechanochromic luminescence, due to transformation into the amorphous state upon grinding the crystalline powder. Interestingly, rubbed films of CSB-5 prepared on glass substrates exhibited a pronounced emission color change from orange to green when exposed to UV light. This response is the result of a photochemical reaction that occurs in the amorphous state and which causes a decrease of the excimer emission sites so that the emission color changes from excimer to monomer. The crystalline material did not display such a photoinduced emission color change and the difference in photochemical reactivity between crystalline and amorphous states was exploited to pattern the emission color of rubbed films.     

磷脂酰胆碱LB单分子膜诱导下KDP晶体取向生长的研究

有机超薄膜诱导晶体生长是在化学、物理与生物多门学科相互交融的基础上发展起来的新兴学科 ,并逐渐成为仿生合成的重要分支 [1] .目前的研究重点主要集中于以有机化合物 LB膜作为模板剂诱导生物矿化材料上 [2～ 5] .磷脂 LB膜是生物膜的简化模型体系 [6 ] ,用它作模板剂将使该领域的研究进一步接近生物体系 .对晶体而言 ,修饰晶体材料的特征对于改善和测定材料的光学性能至关重要 [2 ] ,但目前有关上述领域的研究几乎均是空白 .KH2 PO4 ( KDP)晶体是性能优良的非线性光学材料 [7] ,本文首次以磷脂分子 LB膜作为模板剂诱导 KDP的晶化…     

Water-in-Oil Dispersion for KH2PO4 (KDP) Crystal CMP

Chemical mechanical polishing (CMP) has become an essential process in the manufacturing of advanced microelectronic devices. More recently, CMP has also been applied to the process of other advanced materials such as optical crystals and thin films. Typically, a CMP slurry is formulated as an aqueous dispersion which may contain abrasive particles, activating agent, passivating agent, surfactant, etc. Due to its sensitivity to water, hygroscopic crystals must not be processed with aqueous based slurry. In this study, a new abrasive-free system based on water-in-oil microemulsion was investigated to address this challenge. More specifically, a dispersion made of dodecanol, Triton X-100, and water was studied for its potential application in KH₂PO₄(KDP) crystal processing. In this unique polishing system, water molecules are caged into micelles so the reaction between KDP and water is controlled. As a result, the static etch rate of the substrate surface is minimized. During polishing process, the frictional action between crystal surface and pad leads to the release of reactive water molecules. The material removal is, thus, enhanced. In this paper, the techniques used to characterize such abrasive-free system were first introduced. The water-in-oil structures were characterized and confirmed by conductivity, dynamic lighting scattering and dynamic nuclear magnetic resonance (NMR) measurements. The performance of this system on the process of KDP crystals was then discussed. The static etch rate and the material removal rate in polishing process were measured under various conditions in order to elucidate the polishing mechanism. Finally, the potential application of such a novel nonaqueous polishing system in CMP beyond KDP crystals is discussed.     

Synthesis, growth and characterization of new borate-mixed crystals of type (NH4)1-xKxB5O8

New borate-mixed crystals of type (NH4)1-x KxB5O8 were grown from aqueous solution by slow solvent evaporation method. The mixed crystals were confirmed by atomic absorption studies (AAS) and characterized by X-ray diffractometry (XRD), Fourier transform infrared (FT-IR), Fourier transform Raman (FT-Raman), optical absorption and solubility studies. The second harmonic generation efficiencies of the parent and mixed crystals were studied and compared with that of KDP.     

Crystal Structure and Properties of a Sodium Terbium Borate Na2.67Tb2.11B3O9

A new nonlinear optical crystal of sodium terbium borate (Na2.67Tb2.11B3O9, Mr=573.14) was synthesized by solid reaction method. The colorless transparent single crystals were grown from the high temperature solution by employing NaBO2 as flux. The structure was determined by single-crystal X-ray diffraction method. The compound crystallizes in the orthorhombic system, space group Amm2 with a=5.0744(10), b=10.990(2), c=6.9078(14) , V=385.24(13) ·3, Dc=4.941 g/cm3, F(000)=250, Z=2, μ=9.205 mm-1, the final R=0.0253 and wR=0.0610. Its three-dimensional network structure is constructed from isolated BO33-, Na(1)O8, Na(2)O6, Na(3)O6 and Tb(1)O9 polyhedra. Variable-temperature magnetic susceptibility measurements show the compound is paramagnetic (μj=7.04 μb). The intensity of the second harmonic generation of Na2.67Tb2.11B3O9 is 2.5 times that of KDP.     

Synthesis, growth, structural, spectroscopic and optical studies of a new semiorganic nonlinear optical crystal: L-valine hydrochloride

Single crystals of a new semiorganic nonlinear optical (NLO) material, L-valine hydrochloride (LVHCl), having dimensions up to 20 mm x 6 mm x 4 mm have been grown by slow evaporation solution growth technique. Single crystal X-ray diffraction studies confirm that the grown crystal belongs to the monoclinic system. The functional groups presented in the crystal were confirmed by Fourier transform infrared (FTIR) technique. Optical transmission spectrum shows very low absorption in the entire visible region. Differential thermal and thermogravimetric analyses confirmed that the crystal is stable up to 211 degrees C. The powder second harmonic generation (SHG) efficiency of LVHCl is 1.7 times efficient as potassium dihydrogen phosphate (KDP).     

Influence of organic dyes on the thermal,mechanical, and optical properties of l-arginine trifluoroacetate (LATF) single crystals

Bulk single crystals of pure and organic dyes (rhodamine, amaranth, and methyl orange) admixture l-arginine trifluoroacetate were grown by slow evaporation technique. The cell parameters and crystallinity of pure and dyes-mixed LATF were confirmed by powder X-ray diffraction analysis. Thermal analysis (TG/DTA, DSC) reveals the purity of the sample and no decomposition is observed up to melting point. In the TG trace of pure LATF, methyl orange: LATF, amaranth: LATF and rhodamine: LATF it is observed that the crystals were thermally stable up to 488, 485, 483, and 484.14 K, respectively. The crystals are further characterized using UV–Vis analysis, microhardness analysis, and EDAX analysis. By plotting log P versus log d, the value of the work hardening coefficient "n" was found to be 1.95, 0.52, 0.8, and 0.88 for pure, methyl orange, amaranth, and rhodamine dyes-doped LATF grown crystals, respectively. Second harmonic generation efficiency of pure and dye admixture LATF crystals was measured using Kurtz and Perry powder test, the efficiency of methyl orange, amaranth, and rhodamine dyes-doped LATF crystal is 2.7, 2.6, and 2.07 times greater than KDP, where as the efficiency of LATF pure is 2.5 times greater than that of KDP.     

New second-order NLO materials based on polymeric borate clusters and GeO4 tetrahedra: a combined experimental and theoretical study

Three novel rubidium borogermanates with three types of noncentrosymmetric structures, namely, RbGeB(3)O(7), Rb(2)GeB(4)O(9), and Rb(4)Ge(3)B(6)O(17), have been synthesized by high-temperature solid-state reactions in platinum crucibles. The structure of RbGeB(3)O(7) features a three-dimensional (3D) anionic framework composed of cyclic B(3)O(7) groups corner-sharing GeO(4) tetrahedra. The structure of Rb(2)GeB(4)O(9) shows a 3D anionic framework based on B(4)O(9) clusters connected by GeO(4) tetrahedra via corner sharing. The structure of Rb(4)Ge(3)B(6)O(17) is a novel 3D anionic framework composed of cyclic B(3)O(8) groups, Ge(2)O(7) dimers, and GeO(4) tetrahedra that are interconnected via corner sharing. Second harmonic generation (SHG) measurements indicate that RbGeB(3)O(7), Rb(2)GeB(4)O(9), and Rb(4)Ge(3)B(6)O(17) display moderate SHG responses that are approximately 1.3, 2.0, and 1.3 × KH(2)PO(4) (KDP), respectively, which are slightly smaller than those from theoretical calculations (about 3.7, 2.8, and 2.4 × KDP, respectively).     

Quantum chemistry of hydrogen-bonded materials. Ferroelectrics and antiferroelectrics

Some aspects of application of quantum chemical approaches and methods in the microscopic theory of hydrogen-bonded ferroelectrics and antiferroelectrics, as well as their deuterated analogs, were reviewed in the context of original works of the authors. Calculations of the spontaneous polarization of KH₂PO₄ (KDP) and charge transfer “channels” in transition of KDP and other H-bonded crystals from paraphase to an ordered phase were discussed, as well as the factors responsible for difference in the ferroactive behavior between KDP and NH₄H₂PO₄ (ADP). In terms of the dynamic Ising model and in the mean field approximation, the potentialities of quantum chemical approaches were analyzed as applied to examination and prediction of the results of order-disorder structural phase transitions in M₃H(AO₄)₂ family materials, 5X derivatives of 9-hydroxyphenalenone, and crystalline chromous acid α-HCrO₂ in relation to deuteration of the H-bonds in these crystals.