Doped Potassium Dihydrogen Phosphate Research Articles

Remarkable effect of Ni2+doping on structural, second harmonic generation, optical, mechanical and dielectric properties of KDP single crystals

The nonlinear optical single crystals of pure and Ni2+ doped potassium dihydrogen phosphate (KDP) were successfully grown by slow evaporation solution growth technique. The effects of the addition of Ni2+ with different molar concentration have been studied by powder X-ray diffraction, FT-Raman, second harmonic generation, microscopic and dielectric studies. Its crystallinity was assessed by the FT-Raman technique and its surface, structural imperfections were recorded using high resolution microscope, which clearly reveals that the doping is showing considerable effect on the samples. The SHG measurements also carried out on pure and doped samples, which reveal the relative SHG efficiency has been enhanced due to doping. The optical activities were studied by UV–vis-NIR technique and reveals high optical transparency in doped samples. The remarkable enhancement in mechanical strength was observed due to doping. The enhanced dielectric constant and low dielectric loss confirms that the grown crystals with doping are superior to pure crystals and may be used in optoelectronic devices.

Optical and dielectric studies of KH2PO4 crystal influenced by organic ligand of citric acid and l-valine: A single crystal growth and comparative study

In the present study pure, citric acid (CA) and l-valine (LV) doped potassium dihydrogen phosphate (KDP) crystals have been grown with the aim to investigate the nonlinear optical applications facilitated by UV–visible, third order nonlinear optical (TONLO) and dielectric properties. The structural parameters of grown crystals have been confirmed by single crystal X-ray diffraction analysis. The enhancement in optical transparency of KDP crystal due to addition of CA and LV has been examined within 200–900nm by means of UV–visible spectral analysis. In addition, the transmittance data have been used to evaluate the effect of dopants on reflectance, refractive index and extinction coefficient of grown crystals in the visible region. The Z-scan analysis has been performed at 632.8nm to identify the nature of photoinduced nonlinear refraction and nonlinear absorption in doped KDP crystals. The influence of π-bonded ligand of dopant CA and LV on TONLO susceptibility (χ3), refractive index (n2) and absorption coefficient (β) of KDP crystals has been evaluated to discuss laser assisted device applications. The decrease in dielectric constant and dielectric loss of KDP crystal due to addition of CA and LV has been explored using the temperature dependent dielectric studies.

Growth, optical and spectroscopic studies of l-cysteine doped KDP single crystals

Optically cleared single crystals of pure and l-cysteine doped potassium dihydrogen phosphate (KDP) possessing excellent nonlinear optical properties have been grown from aqueous solution by the slow evaporation technique. The lattice parameters of the grown crystals are confirmed by single crystal X-ray analysis. The well defined sharp peaks in the powder X-ray diffraction pattern reveals the crystalline perfection and the EDAX spectrum confirms the presence of l-cysteine dopant in the lattice of the parent crystal. The UV–visible spectral study confirm the improved transparency for the doped crystal, ascertaining the inclusion of metal ion in the lattice. Photoluminescence studies indicate that the grown crystals have a green fluorescence emission. FTIR spectral analysis carried out on the materials confirm the presence of functional groups. The vickers hardness test brings forth higher hardness value for doped KDP as compared to pure KDP crystal.

Single crystal growth, structural, optical, mechanical, dielectric and thermal studies of formic acid doped potassium dihydrogen phosphate crystal for NLO applications

Optically transparent formic acid (FA) doped potassium dihydrogen phosphate (KDP) crystal of dimension 21×15×9 mm3 has been grown by slow evaporation solution technique (SEST). The X‐ray diffraction (XRD) technique was used to confirm the cell parameters and the shifts in peak positions of identified reflecting planes. The incorporation of FA in KDP has been qualitatively analyzed by fourier transform infrared analysis. The UV‐visible absorption spectrum of crystals has been recorded in the range of 200 to 900 nm and the doped KDP crystal is found to have improved optical parameters than pure KDP. The color centered photoluminescence emission spectrum of grown crystal has been illustrated in visible region. The mechanical behavior of pure and doped KDP crystal has been investigated using the Vicker's microhardness analyzer and hardness parameters have been calculated. The effect of FA on thermal stability of KDP crystal was examined by means of thermogravimetric and differential thermal analysis. The temperature dependent dielectric behavior of crystals was studied.

Effect of crystal violet dye on the optical, dielectric, thermal and mechanical properties of directed KDP single crystal

Crystal violet dye doped potassium dihydrogen phosphate single crystals were grown by Sankaranarayanan–Ramasamy method and slow cooling method with the vision to improve the properties of the crystal. The objective of this study is to show how organic dyes influence the growth, morphology of potassium dihydrogen phosphate crystal. The grown crystals were of size up to 130mm in length and 10mm in diameter. The incorporation of dye is more in the crystal grown by slow evaporation method compared to the crystal grown by Sankaranarayanan–Ramasamy method. The addition of dye improves the quality and yields more than 90% transparent crystals and growth rate is also very high. Thermal stability of the doped crystal is high compared to pure crystal. Low dielectric loss shows that the grown crystal contains minimum defects. The optical transmission, thermal and mechanical stability show the suitability of the ingot for optical applications.

Growth and Characterization of Boric Acid Doped KDP Single Crystals Grow by Slow Evaporation Method

Boric acid (0.25, 0.5, 1.0 %wt) doped Potassium Dihydrogen Phosphate (KDP) bulk single crystals were grown from aqueous solutions by slow evaporation method. Solubility and nucleation curves were studied. The grown crystals were confirmed by powder X-ray diffraction analysis. Functional groups presented in the grown material have been identified using FTIR spectra. The temperature stability of the crystal has been confirmed by TGA. The mechanical strength was analyzed using Vickers hardness measurement.

Nucleation Kinetics of L-Arginine, L-Lysine and L-Alanine Doped Potassium Dihydrogen Phosphate Crystals

The solubility, induction period and nucleation parameters of pure and amino acids like L-arginine, L-lysine and L-alanine doped potassium dihydrogen phosphate (KDP) crystals have been determined. Solubility study of pure and amino acids doped KDP crystals were carried out for different temperatures. The induction period was measured at different supersaturation level. The nucleation parameters like interfacial tension, radius of critical nucleus and energy of formation were calculated based on the classical theory of nucleation. Values of different parameters were found to be larger for amino acid doped crystals than pure KDP crystal.

Growth and Characterization of Pure and L-Alanine Sodium Nitrate doped Potassium Dihydrogen Phosphate Single Crystals

Growth and Characterization of Pure and L-Alanine Sodium Nitrate doped Potassium Dihydrogen Phosphate Single Crystals

Growth of Ferroelectric Tri-Glycine Sulphate Doped Potassium Dihydrogen Phosphate Single Crystal and Its Characterization

Potassium dihydrogen phosphate (KH2PO4, KDP) single crystals have been long studied due to their non-linear optical property. Also, these crystals can exhibit some ferroelectricity when applying an external electric field. In the absence of the external field, the remaining polarization is weak, and hence, the applications of KDP in the electronic industry are limited. In order to enhance the ferroelectricity of the KDP crystals, tri-glycine sulphate (TGS) was added to the KDP solution and then the doped crystals were grown using the slow evaporation method. The results show that the properties of TGS doped KDP crystals are similar to those of the pure KDP. However, the ferroelectricity of the TGS doped KDP has been improved by the small addition of the TGS. These reveal that the TGS molecules may disrupt the KDP lattice and hence, lead to the enhancement of the built-in polarization.

A Study on Structural, Optical, Electrical and Etching Characteristics of Pure and L-Alanine Doped Potassium Dihydrogen Phosphate Crystals

Pure potassium dihydrogen phosphate (KDP) crystals and KDP doped with L-alanine have been grown by slow evaporation technique at room temperature. Grown crystals have been characterized using powder X-ray diffraction, (XRD), Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). The presence of L-alanine into pure KDP crystal was confirmed by FTIR and EDX spectra. Crystal structure has been studied by XRD. Pure KDP and L-alanine doped KDP crystals both possessed tetragonal structure. The transparency is found to increase with the increase of doping concentrations of the grown crystals as observed by UV-Vis spectra. A.C. electrical conductivity of grown crystals along the growth axis was carried out at various temperatures ranging from 35?C - 400?C. Dielectric constant and dielectric losses are measured as a function of temperature and this study reveals the contribution of space charge polarization. Crystal defects and surface morphology are studied by dissolution solvent technique and reveals the step growth mechanism for both pure and doped crystals.

Growth and Characterization of L-Arginine Doped Potassium Dihydrogen Phosphate Single Crystals Grown by Sankaranarayanan-Ramasamy Method

Single crystals of L-arginine doped potassium dihydrogen phosphate (KDP) were grown by both conventional and Sankaranarayanan-Ramasamy (SR) methods. The grown crystals were characterized by powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, optical transmission, dielectric constant, and Vickers microhardness. The reflectance and extinction coefficients of the grown crystal were calculated and discussed. The variations of dielectric constant, dielectric loss, a.c. resistivity and a.c. conductivity were studied. The lower values of dielectric loss due to fewer defects were observed in SR grown L-arginine doped KDP crystals. Vickers microhardness study showed higher mechanical stability in SR method grown crystals.

Experimental Evidence for the Influence of Mn3+ Concentration on the Impurity Incorporation and Habit Modification Mechanism of Potassium Dihydrogen Phosphate

High resolution X-ray diffraction is applied to study Mn3+ doped potassium dihydrogen phosphate (KDP) single crystals as a function of dopant concentration with quantitative dopant composition within the crystals being assessed using Rutherford backscattering spectroscopy (RBS). Synchrotron radiation high resolution X-ray multiple diffraction studies using both the Renninger scanning and two-dimensional angular mapping techniques are consistent with the Mn3+ ionic complex entering the crystal lattice via a substitutional incorporation mechanism for Mn3+ at a concentration of 0.1 wt %. For a higher Mn concentration of 0.9 wt %, the data indicate incorporation via an interstitial mechanism associated with a decrease in lattice perfection (an increased mosaic spread). This analysis is supported through X-ray powder diffraction studies which reveal lattice contraction for lower dopant levels with lattice dilation for the higher dopant levels. The potential impact of this observation on the associated crystal growth habit modification process is discussed.

FT-IR, Thermal and NLO Studies on Amino Acid (L-Arginine and L-Alanine) Doped KDP Crystals

Single crystals of pure and amino acid (L-arginine and L-alanine) doped potassium dihydrogen phosphate (KDP) for second harmonic generation have been grown from low temperature solution growth method by employing slow evaporation of the solvent. FT-IR spectrum of pure and doped KDP crystals confirms qualitatively the doping of the L-arginine and L-alanine in the host crystals. UV-visible spectroscopy shows the improvement in the transparency. Crystal structure has been studied by powder X-ray diffraction. Modification in the lattice parameters has been observed. Improvement in the SHG efficiency was studied by the Kurtz and Perry method. Thermal analysis has been performed on the grown crystals.

Influence of lithium ions on the NLO properties of KDP single crystals

AbstractPotassium Dihydrogen Phosphate (KDP) and its isomorphous deuterated form are popular due to their applications in frequency converters and electro‐optic modulation. Different attempts have been made to dope KDP with inorganic additives, organic materials and amino acids. Since many of the metal ions possess more electro negativity which increases the non centrosymmetry, it is of interest to dope them in KDP. The influence of lithium ion (Li+) on NLO properties of KDP crystal has been studied in the present investigation. Single crystal of Lithium ion doped Potassium Dihydrogen Phosphate (KDP) was grown by slow evaporation technique. The enhancement in SHG efficiency after addition of ion Lithium (Li+) was observed by Kurtz Powder SHG test. It was found that the SHG efficiency of KDP after addition of Lithium ion is 1.33 times more than pure KDP. The crystal structure and cell parameters of grown crystal were determined by X‐ray diffraction. The Energy Dispersive X‐ray analysis (EDAX) gives the chemical composition of grown crystal. The functional groups were identified by FT‐IR spectral analysis. The presence of Lithium in the material of grown crystal was detected by Atomic absorption spectroscopy (AAS). The optical absorption and transmission studies were done by UV‐Visible spectral analysis. The grown crystal was subjected to thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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.

THERMAL, DIELECTRIC STUDIES ON PURE AND AMINO ACID (L-GLUTAMIC ACID, L-HISTIDINE, L-VALINE) DOPED POTASSIUM DIHYDROGEN PHOSPHATE SINGLE CRYSTALS

Amino acids (L-Glutamic acid, L-Histidine, L-Valine) doped potassium dihydrogen phosphate crystals were grown by the solution growth technique. Slow cooling as well as slow evaporation methods were employed to grow these crystals. The concentration of dopants in the mother solution was varied from 0.1 mole % to 10 mole %. The solubility data for all dopant concentrations were determined. The variation in pH and the corresponding habit modification of the grown crystals were characterized with UV - VIS, FT-IR and SHG trace elements, and dielectric studies reveal slight distortion of lattice parameter for the heavily doped KDP crystals. TGA-DTA studies reveal good thermal stability. The dopants increase the hardness value of the material, which also depends on the concentration of the dopants. Amino acids doping improved the NLO properties. The detailed results on the spectral parameters, habit modifications and constant values will be presented.

EPR and Optical Absorption Studies of VO2+ Doped KH2PO4 and KH3C4O8·2H2O Single Crystals

VO2+ doped potassium dihydrogen phosphate (KH2PO4) and potassium tetraoxalate (KH3C4O8 · 2H2O) single crystals and powders are examined by electron paramagnetic resonance and optical absorption spectroscopy. Angular variations of KH2PO4 and KH3C4O8 ·2H2O single crystals show four and two different VO2+ sites, respectively. The local symmetry of VO2+ complexes is nearly axial for both host crystals. The optical absorption spectra show three bands. Spin Hamiltonian parameters are measured and molecular orbital coefficients are calculated by correlating EPR and optical absorption data for the central vanadyl ion

Effect of pyrophosphate on the light scatter in KDP crystal

Pyrophosphate doped potassium dihydrogen phosphate (KDP) crystal was grown from aqueous solution by the temperature lowering method. Light scatter in KDP crystal was detected with the ultramicroscopic method. The light scatter in KDP crystal was aggravated when pyrophosphate was doped into the growth solution, which was distributed ununiformly in prism and pyramidal sectors of KDP crystal. Different effects of pyrophosphate on prism and pyramidal sectors of KDP crystal can explain this case. The transmission in this crystal was measured, showing that pyrophosphate affects the transmission evidently.

Laser Damage Threshold and UV Absorption of Doped Potassium Dihydrogen Phosphate Crystals

The effects of Pb, Ca, and Si impurities on the laser damage threshold and UV absorption of KH2PO4 crystals were studied. The laser damage threshold was found to be ≃6 × 1011 W/cm2 in crystals containing ≃5 × 10–5 wt % and to decrease nonlinearly at higher impurity contents.

Nucleation studies in supersaturated aqueous solutions of chromate doped potassium dihydrogen phosphate

Nucleation studies in supersaturated aqueous solutions of chromate doped potassium dihydrogen phosphate