Pure KDP Crystals Research Articles

Enhanced NLO and antibacterial properties of nicotinic acid-doped KDP crystals: synthesis, growth and characterisation

A biocompatible non-linear optical crystals (458 × 7 mm) of nicotinic acid-doped potassium dihydrogen phosphate (KDP) were grown by the slow evaporation technique at room temperature and their structural study was confirmed by single-crystal X-ray diffraction. Further, the presence of functional groups and elements were verified using Fourier transform infra-red and Energy dispersive X-ray studies. The optical properties of these crystals such as transmission and absorption were analysed by Ultra Violet Visible Near infra-red spectroscopy and the second harmonic generation efficiency was carried out by the Kurtz–Perry powder technique. The mechanical properties of the grown crystal were studied using Vickers’ hardness tester. The grown crystals were involved in an antibacterial activity against certain potentially threatening microbes such as Bacillus subtilis, Escherichia coli, Staphylococcus aureu and Klebsiella pneumoniae. The dopant efficiently screened the bacteria than that of the pure KDP crystal.

Nonlinear optical response of nanocomposites based on KDP single crystal with incorporated Al2O3*nH2O nanofibriles under CW and pulsed laser irradiation at 532 nm

Optical properties and nonlinear optical response due to the CW and pulsed laser radiation self-action at 532nm were studied in composites based on KDP single crystals with incorporated nanofibriles of nanostructured oxyhydroxide of aluminum (NOA). It was shown a high optical quality and structural homogeneity of nanocomposites KDP:NOA by the transmittance spectra, elastic optical scattering and XRD analysis. It was observed manifestation of the second harmonic generation efficiency enhancement in the KDP:NOA versus the nominally pure KDP (λ=1064nm, τ=1ns) that is correlated with efficient refractive index self-modulation Δn∼10−4 (λ=532nm, τ=30ps). In the pyramidal and prismatic growth sectors of the nominally pure KDP crystal it was shown opposite signs of the photoinduced variations both of the refractive index and of the optical absorption/bleaching due to resonant excitation of the native defects at 532nm. It should be considered for the wide-aperture laser frequency KDP family based convertors fabrication.

Growth, structural, UV–visible, SHG, mechanical and dielectric studies of bis-thiourea zinc chloride doped KDP crystal for NLO device applications

Optically transparent 11 × 10 × 4 mm3 bis-thiourea zinc chloride (BTZC) doped potassium dihydrogen phosphate (KDP) crystal has been grown by slow evaporation solution technique. The cell parameters of the grown crystal have been determined by single crystal X-ray diffraction analysis. The incorporation of BTZC in KDP crystal has been qualitatively analysed by FT-IR spectral analysis. The optical transparency and vital optical constants of BTZC doped KDP single crystals have been evaluated in the range of 200–900 nm. The mechanical behaviour of pure and doped KDP crystals has been investigated under the Vickers microhardness studies. The dielectric parameters of grown crystal have been investigated within the frequency range of 10–100 KHz. In Kurtz–Perry powder test, the second harmonic generation (SHG) efficiency of BTZC doped KDP crystal is found to be 1.65 times that of KDP material.

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.

Influence of amaranth dye on the growth and properties of KDP single crystal

Amaranth dye doped KDP single crystals were grown by slow cooling seed rotation method with the vision to improve the properties of the crystal. The grown crystals were of size up to 53×20×50mm3. The grown crystals were subjected to FTIR, UV–vis photoluminescence, microhardness and laser damage threshold studies. The addition of dye improves the growth rate of the crystals. Photoluminescence (PL) emission spectra of amaranth doped KDP crystals are practically identical. Amaranth increases the mechanical strength and laser damage threshold of the grown crystals compared to pure KDP crystals.

Effect of Hippuric Acid on the Growth, Structural and Optical Properties of Non Linear Optical Crystals

Non-linear optical potassium dihydrogen phosphate (KDP) and ammonium dihydrogen phosphate (ADP) single crystals with 1 mol% of hippuric acid dopant were grown from aqueous solution by employing slow evaporation technique. With appropriate dopants, the KDP and ADP crystals exhibit several desirable properties. Crystallinity of the grown crystals was studied by powder XRD analysis. The bonding structure and molecular associations were analyzed by FTIR spectroscopy. It also confirms the functional groups present in the grown crystals. UV-Vis-NIR spectral analysis was carried out to study the optical characteristics of the crystals which reveal that the cutoff wavelength for both hippuric acid doped KDP and ADP crystals is around 300 nm. Second harmonic generation (SHG) test adopting the Kurtz Perry technique revealed that the SHG efficiency has increased due to doping when compared with pure KDP and ADP crystals.

Linear and nonlinear optical properties of KDP crystals with incorporated Al2O3⋅nH2O nanoparticles

Optical and nonlinear optical properties of a novel composite system based on KDP single crystals with embedded nanoparticles of nanostructured oxyhydroxide of aluminum (Al2O3·nH2O, NOA), were studied. KDP crystals with NOA nanoparticles (KDP:NOA) possess high optical quality and homogeneity. Optical spectroscopy showed the presence of an absorption band at 270nm caused by NOA nanoparticles incorporated in the KDP matrix. There was observed an enhancement of nonlinear refractive index and inversion of its sign in KDP:NOA crystals in comparison with nominally pure KDP crystals under excitation of picosecond laser pulses. The obtained results demonstrate that KDP:NOA is a promising composite material for optoelectronics and nonlinear optics.

Synthesis, growth and characterization of a semiorganic nonlinear optical material: l-Threonine cadmium chloride single crystals

A semiorganic nonlinear optical single crystal was grown from aqueous solution by slow evaporation method at room temperature. The characterization of the crystal was made using single crystal and powder X-ray diffraction analysis and it was found to be the LTCC crystallized in orthorhombic crystal system with noncentro symmetric space group. The UV–vis spectroscopic study reveals that the crystal has good optical transparency and lower cut off wavelength was found to be 332nm. The presence of functional groups was identified by FTIR spectra. The percentage of carbon, hydrogen and nitrogen was analyzed by elemental analysis. The microhardness was tested using Vicker's microhardness tester. The nonlinear optical property was confirmed by Kurtz–Perry powder technique and it was found to be 0.7 times higher than pure KDP crystal.

Growth, structural and optical characterization of a new nonlinear optical crystal – hippuric acid doped potassium di hydrogen phosphate

Potassium di hydrogen phosphate (KDP) is an efficient nonlinear optical crystal employed in frequency conversion applications. 1mol% hippuric acid doped potassium di hydrogen phosphate (HAKDP) crystals with the dimensions 35×8×4mm3 were grown using the slow evaporation technique. The grown HAKDP crystal is iso-structural with pure KDP, but a variation in the crystallographic parameters was observed. The UV–VIS–NIR study suggests that the crystal is highly transparent in the region 340–1200nm. The functional groups present in the grown crystal were observed in the FTIR analysis. The powder SHG test performed on the grown crystal revealed the NLO efficiency of the crystal has increased due to doping when compared with pure KDP crystal.

Vickers Micro-Hardness Studies of Amino Acids (L-Histidine, L-Threonien and DL-Methionine) Doped KDP Crystals

Pure and various amino acids (L-histidine, L-threonine, DL-methionine) doped KDP crystals were grown by slow solvent evaporation technique. The doping of amino acids was confirmed by C, H, N analysis, FTIR spectroscopy and paper chromatography .Pure and doped KDP crystals were subjected to Vickers microhardness studies. Indentations were made on smooth (100) as grown faces of pure and doped crystals. The Vickers indenter loads were varied from 0.298 N to 0.981 N in order to study the effect of load on microhardness. A number of indents were made at each load and the mean diagonal length (d) was used in calculating the Vickers Hardness Number (HV). The Vickers micro-hardness decreased as amino acid doping level was increased indicating that the KDP crystals became softer after doping. The Indentation size effect (ISE) the Kicks law as well as PSR model was verified for all samples. The values of the load independent hardness and the Newtonian pressure (W) were higher in pure KDP crystals than the amino acids doped KDP crystals. It was found that as the doping concentration of amino acids increased the values of load independent hardness and Newtonian pressure decreased. Hays and Kendall law analysis was also applied to the hardness data.

Comparative studies of glycine added potassium dihydrogen phosphate single crystals grown by conventional and Sankaranaryanan–Ramasamy methods

Glycine added potassium dihydrogen phosphate (KDP) crystals have been grown by slow evaporation solution technique, slow cooling along with seed rotation and Sankaranaryanan–Ramasamy (SR) method. The size of the grown crystal in slow cooling method was 35×25×20mm3 and in SR method it was 20mm in diameter and 110mm in length. The grown crystals were subjected to powder X-ray diffraction, UV–Vis, thermal analysis, Vickers microhardness, dielectric, laser damage threshold, higher resolution X-ray diffraction (HRXRD) and nonlinear optical (NLO) studies. All the grown crystals have good transparency in the entire visible region. In order to determine mechanical strength of crystal, Vickers micro-hardness measurement was carried out. Dielectric study reveals higher dielectric constant and low dielectric loss for SR method grown crystal. High laser damage threshold was observed in SR method grown glycine added KDP crystal compared to SR method grown pure KDP crystal. The second harmonic efficiency of the glycine added KDP is increased compared to pure KDP.

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.

Investigation on growth features and crystal structures of pure and metal ion (Mn2+) doped KDP single crystals

To reveal clearly the doping effect on the growth and properties of KDP single crystals, bulk concentration 1.0mol% and 5mol% of MnCl2 (Mn2+) was doped in KDP single crystals by using slow evaporation method. Interesting results like nucleation, rate of growth, and defect formations were found during the investigation. The different stages of live growth are recorded with the help of inverted microscope. Powder X-ray diffraction (XRD) analyses confirm the tetragonal structure of pure and doped KDP. The variation in the intensity of diffraction peaks shows the minute change in lattice parameters in correlation with morphology of varying Mn2+ doping concentrations. The above studies further reveal that the structure and morphology of the doped crystals are slightly distorted compared to the pure KDP crystal. The optical properties of the grown crystals have been investigated by using UV–visible spectra. The band gap energy for the doped KDP crystals was calculated from optical transmission spectrum.

High-temperature Raman spectra of KDP:Ni crystal

High-temperature Raman scattering measurements of KDP doped with Ni (1% weight) were performed over the spectral range 50–1200cm−1. The X-ray powder diffraction patterns taken at room temperature and analyzed by Rietveld refinement showed that doped samples of KDP:Ni have the same tetragonal structure of a pure KDP crystal, but with a contraction of the crystalline cell. The behavior of the high-temperature Raman spectra indicate that two phase transitions occur, one at 413K and another one at 443K. These phase transitions occur at temperatures below the thermal dehydratation point, 488K. DTA and TGA measurements reveals that KDP:Ni and pure KDP have the same thermal dehydratation temperature.

Growth, Optical and Dielectric Studies on Pure and L-Lysine Doped KDP Crystals

Optically good quality single crystals of pure and L-lysine monohydrochloride-doped KDP crystals have been grown by a slow evaporation method. The grown crystals have been subjected to optical and dielectric studies. The UV-Vis spectrum shows the transmitting ability of the crystals in the entire visible region and transmittance percentage is increased for the doped KDP crystals. From the dielectric study, it is found that the dielectric constant and the dielectric loss of L-lysine-doped KDP crystals were lower than the pure KDP crystals. Hence L-lysine-doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals.

Influence of Ca2+ ions on the habit of KDP crystals

A few KDP (KH2PO4) and KDP:Ca 2+ (CaCl2) single crystals were grown based on the temperature reduction method. Investigations show that the presence of bivalent ions like Ca 2+ could be a cause of retarded growth rate and induced crystalline lattice defects. Here the pure KDP crystals are compared with KDP:CaCl2. Crystals of both types were also studied in aspect of other structural and optical properties.

Solution growth of KDP single crystals doped with titanium dioxide nanoparticles

Pure KDP single crystals and KDP crystals doped with TiO 2 nanocrystals were grown by the method of temperature reduction from aqueous solutions. Adsorption of the phosphate-ions on the surface of TiO 2 particles was studied by FTIR spectroscopy. It was shown that the nanoparticles with adsorbed H 2PO 4 – and (H 2PO 4) 2 2–anions were incorporated predominantly into the positively charged face (1 0 1) of the pyramidal sector of KDP. High-resolution X-ray three-crystal diffractometry (TCD) investigation of the as grown samples of KDP + TiO 2 revealed the presence of the turns of the growth layer “stacks” up to 3 arcsec in the growth sectors {1 0 0} and {1 0 1}. The observed thickness of these “stacks” was of the order of 20–30 μm. For KDP + TiO 2 crystals there was found a relative change of the crystal lattice parameter (Δ d/ d) caused by incorporation of TiO 2 nanoparticles into the boundaries of the growth layers. This gave rise to the formation of a semicoherent binding on the interface between the captured TiO 2 and the matrix. No essential influence of the nanoparticles on the laser damage threshold of KDP with 10 −5 wt.% of TiO 2 was established.

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‐alanine doped KDP crystals

AbstractPotassium Dihydrogen Phosphate (KDP) is an excellent inorganic nonlinear optical (NLO) material with different device applications. Most of amino acids possess NLO property; therefore, it is of interest to dope them in KDP crystals. In the present study, amino acid L‐alanine doped KDP crystals were grown by slow aqueous solvent evaporation technique. The doping of L‐alanine was confirmed by the paper chromatography, the CHN analysis and the FT‐IR spectroscopy. The powder XRD was carried out to assess the single phase nature of the samples. The effect of doping on thermal stability of the crystals was studied by TGA and the kinetic and thermodynamic parameters of dehydration were evaluated. As the amount of doping increased the thermal stability of crystals decreased. However, the second harmonic generation (SHG) efficiency and the UV‐Vis spectroscopy studies indicated that as the L‐alanine doping increased the SHG efficiency and optical transmission percentage increased. The dielectric behavior of the samples has been studied. The variation of dielectric constant, dielectric loss (tanδ), a.c.resistivity and a.c.conductivity with frequency of applied field in the range from 100 Hz to 100 kHz was studied. The dielectric constant and dielectric loss decreased with increase the value of frequency of applied field. The dielectric constant and the dielectric loss values of L‐alanine doped KDP crystals were lower than the pure KDP crystals. The results are discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)