Synthesis,spectral, thermal and optical characterization of benzyltributylammonium trichlorobarium(II) monohydrate crystal

A new nonlinear optical semiorganic crystal, benzyltributylammonium trichlorobarium(II) monohydrate was grown by slow evaporation solution growth method at ambient temperature. The powder X-ray diffraction pattern of the crystal confirms its crystallinity. The absorption spectrum of the material shows a peak at 265 nm and no absorption observed in the entire visible region indicates that the compound can be used as a nonlinear optical material. The optical transmittance spectrum of the grown crystal shows a lower cut-off wavelength at 235 nm with transparency of 88%. Thermal stability of the crystal was studied by thermogravimetry-differential thermogravimetry and differential thermal analyses (TG-DTG and DTA). The differential scanning calorimetry (DSC) analysis shows thermal anomalies in the heating and cooling cycles that indicates the occurrence of a first order phase transition. The various characteristics absorption chemical bands and BaCl₃⁻ vibration were assigned through fourier transform infrared (FTIR) spectral analysis. The second harmonic generation efficiency (SHG) of the grown crystal was analyzed by Kurtz–Perry powder technique using Nd:YAG laser. The dielectric constant and dielectric loss of the compound decrease with increase in frequency.     

Growth and characterization of pure and doped bis thiourea zinc acetate: Semiorganic nonlinear optical single crystals

Metal–organic coordination complex single crystals bis thiourea zinc acetate (BTZA) and Cd²⁺ doped BTZA have been synthesized and grown successfully by slow-cooling technique from their aqueous solutions. Single crystals of pure and Cd²⁺ doped BTZA with dimensions of 35 × 4 × 2 mm³ and 10 × 5 × 6 mm³, respectively were obtained with well defined morphology. The as grown single crystals are characterized by single crystal XRD studies and melting point measurements which reveal the incorporation of metallic dopants has not changed the structure of the parent crystal. The powder X-ray diffractogram of the grown crystals has been recorded and the various planes of reflection identified shows shift in the peak positions. The metal coordination with thiourea through sulphur in pure and Cd²⁺ doped BTZA were ascertained by FTIR studies and optical absorption study to identify the UV cut-off range. The presence of metals in pure and Cd²⁺ doped BTZA crystal lattice were confirmed by atomic absorption spectroscopy (AAS). The thermal decomposition of pure and Cd²⁺ doped BTZA crystals were investigated by thermo gravimetric analyses (TGA) and differential thermal analysis (DTA) indicate that doped crystals are more stable than pure crystals. The dielectric response of the crystals were studied in the frequency range 100 Hz–5 MHz at different temperatures and the results are discussed. Second harmonic generation (SHG) measurement confirms that the pure and Cd²⁺ doped BTZA have nonlinear optical (NLO) property. Laser damage threshold value of 12.44 MW/cm² has been determined using Q-switched Nd:YAG laser operating at 1064 nm and with 8 ns pulses in single shot mode for pure BTZA single crystal is reported for the first time.     

Growth,linear and nonlinear optical studies on guanidinium 4-nitrobenzoate (GuNB): An organic NLO material

Single crystals of guanidinium 4-nitrobenzoate (GuNB) were grown using solvent evaporation technique by mixing aqueous solutions of guanidine carbonate and 4-nitrobenzoic acid at ambient temperature. X-ray diffraction analysis characterized the unit cell parameters of the grown crystal and the crystal belongs to monoclinic system. The optical properties of the grown crystal have been studied by means of transmission measurements in the wavelength region between 200 and 1200 nm. The optical constants such as refractive index (n) and extinction coefficient (k) have been determined from the transmittance data. The optical band gap (E_g), the real and imaginary parts of the dielectric constant of the grown crystal was determined. Second harmonic generation (SHG) efficiency of the grown crystal has been studied using Nd:YAG laser and was measured as 3.2 times that of KDP. The low dielectric constant suggests the suitability of this compound material for NLO applications.     

Synthesis and growth of sodium bitartrate monohydrate a new organometallic nonlinear optical single crystal

Sodium bitartrate monohydrate (SBTMH) a new organometallic nonlinear optical material, with molecular formula, [C₄H₅NaO₆ · H₂O] has been synthesized at ambient temperature. Spectral, thermal and optical techniques have been employed to characterize the new material. Bulk single crystals of size 13 × 4 × 4 mm³ of SBTMH have been grown by slow cooling method. The unit cell parameters of the grown crystal were determined by single crystal XRD. Functional groups present in the sample were identified by FTIR spectral analysis. Thermal stability of SBTMH was determined using TGA/DTA. The grown crystals exhibit nonlinear properties. The dielectric response of the crystal with varying frequencies was studied. The optical transparency range and the lower cut-off wavelength of the material were identified from the UV–vis–NIR absorption spectrum.     

Crystal growth,spectral and NMR studies of nonlinear optical crystal: L-valinium picrate

Organic nonlinear optical material, L-valinium picrate (LVP) was synthesized by slow evaporation solution growth method. The synthesized material was purified by repeated recrystallization. Single crystals of LVP were grown by slow evaporation method using water as solvent. The cell dimensions were obtained by X-ray diffraction study and crystal system was confirmed as monoclinic. The transmission spectrum of LVP was recorded by UV–Vis-NIR spectrometer in the range between 190 nm and 1100 nm which addressed the high percentage of transmission of the sample in the entire visible region. The presence of functional groups was studied by FT-IR analysis. The chemical environment of carbon and hydrogen in the proposed structure of LVP crystal was confirmed by FT NMR studies. The Kurtz-Perry powder SHG measurement was confirmed the frequency doubling of the crystal.     

Structural,optical and mechanical property analysis of magnesium sulphate admixtured l-Threonine: A novel optoelectronic material

l-Threonine is an important amino acid and famous due to their property of frequency conversion and electro optic modulation. Single crystals of magnesium sulphate admixtured l-Threonine was grown by slow evaporation technique. Good quality single crystal with dimension 58 × 5 × 10 mm³ was harvested after 60 days. The powder X-ray diffraction pattern of the grown crystal has been indexed. The optical transmission spectrum shows that the magnesium sulphate admixtured l-Threonine possess good optical transparency in the entire visible region with Ultra Violet cut-off wavelength at 250 nm. The presence of fundamental functional groups was identified by Fourier Transform Infra Red spectral analysis. The structure of the grown crystal was established using Fourier Transform-Nuclear Magnetic Resonance spectral analysis. The thermal behaviour of the crystal has been discussed by Thermal Gravimetric Analysis and Differential Thermal Analysis. Magnesium sulphate admixtured l-Threonine was characterized by Energy dispersive analysis of X-ray. The second harmonic generation efficiency of magnesium sulphate admixtured l-Threonine crystal is found to be same as that of potassium dihydrogen phosphate crystal.     

Structural,optical and electrical characteristics of a new NLO crystal

A new nonlinear optical (NLO) organic crystal 1-[4-({(E)-[4-(methylsulfanyl)phenyl]methylidene}amino)phenyl]ethanone (MMP) has been grown by slow evaporation technique at ambient temperature. The crystal structure of MMP was determined by single crystal X-ray diffraction. MMP crystallizes in non-centrosymmetric monoclinic system with space group P2₁. The FT-IR spectrum recorded for new crystal confirmed the presence of various functional groups in the material. MMP was found to be thermally stable up to 300 °C. The grown crystal was optically transparent in the wavelength range of 400–1100 nm. The second harmonic generation (SHG) efficiency of the crystal was measured by the classical powder technique using Nd:YAG laser and was found to be 4.13 times more efficient than reference material, urea. Third order nonlinear parameters were measured by employing the Z-scan technique. The laser damage threshold for MMP crystal was determined to be 4.26 GW/cm². The Brewster angle technique was employed to measure the refractive index of the crystal and the values for green and red wavelengths were found to be 1.35 and 1.33, respectively. The dielectric and electrical measurements were carried out to study the different polarization mechanisms and conductivity of the crystal.     

Growth,structural, mechanical,spectral and dielectric characterization of NaCl-added Triglycine sulfate single crystals

Pure and sodium chloride (NaCl)-added Triglycine sulfate (TGS) crystals were grown from aqueous solutions by slow evaporation technique. The values of concentration of dopants in the mother solution were 0.2, 0.6 and 1 mol%. The solubility of the grown samples have been found out at various temperatures. The determination of unit cell parameters was carried out by single crystal XRD method and found that the grown crystals crystallize in monoclinic structure. The dielectric characterization for the pure and NaCl-doped TGS crystals was performed by measuring the dielectric parameters like dielectric constant and dielectric loss with various frequencies in the range 10²–10⁶ Hz and with the temperatures ranging from 30 to 70 °C and this study reveals an increase of dielectric constant and loss with the increase of NaCl concentration. Studies on mechanical properties like microhardness and density of the grown pure and NaCl-doped TGS crystals were carried out. UV–Visible transmittance studies were carried out for the grown samples. A sharp fall in the transmittance is observed at 228 nm for pure and NaCl-doped TGS crystals. Atomic absorption spectroscopic (AAS) study was done on the NaCl-doped TGS crystals to ascertain the presence of Na⁺ ions in the lattice.     

Enhancement of second harmonic generation efficiency: Cs(I)-doped tris(thiourea)zinc(II) sulphate crystals

The effect of dopant cesium (Cs(I)) over a concentration range from 1 to 10 mol% on the growth process, morphology, thermal and optical properties of tri(thiourea)zinc(II) sulfate (ZTS) single crystals grown by slow evaporation solution growth technique has been investigated. Incorporation of Cs(I) into the crystal lattice was well confirmed by energy dispersive X-ray spectroscopy (EDS). The lattice parameters of the as-grown crystals were obtained by single crystal X-ray diffraction analysis. The reduction in the intensities observed in powder X-ray diffraction patterns of doped specimen and slight shifts in vibrational frequencies in fourier transform infrared spectra (FT-IR) indicate the lattice stress as a result of doping. Thermal studies reveal the purity of the material and no decomposition is observed up to the melting point. High transmittance is observed in the visible region and the cut-off λ is ～280 nm. The surface morphology of the as-grown specimens was studied by scanning electron microscopy (SEM). The second harmonic generation (SHG) efficiency of the host crystal is enhanced greatly in the presence of high concentrations of the dopant.     

Customizing optical and dielectric traits of ammonium dihydrogen phosphate (ADP) crystal exploiting Zn2+ ion for photonic device applications

Current investigation is aimed to explore the influence of Zn²⁺ ion on structural, optical and dielectric characteristics of ammonium dihydrogen phosphate (ADP) crystal to explore its widespread suitability for photonic device applications. The slow solvent evaporation technique has been adopted to grow the Zn²⁺ ion influenced ADP (Zn-ADP) crystal. The energy dispersive spectroscopic technique has been employed to determine the constituent elements of Zn-ADP crystal. The optical transmittance of pure and Zn-ADP crystal has been examined within 200–1100 nm by means of UV–visible spectral analysis. The Kurtz–Perry test has been employed to determine the enhancement in second harmonic generation (SHG) efficiency of ADP crystal due to presence of Zn²⁺ ion. The SHG efficiency of Zn-ADP crystal is found to be 3.15 times greater than potassium dihydrogen phosphate (KDP) and 1.79 times higher than ADP. The Z-scan analysis has been performed at 632.8 nm to study the third order nonlinear optical attributes (such as nonlinear refraction (n₂), absorption (β) and cubic susceptibility (χ³)) of Zn-ADP crystal. Dielectric analysis has been carried out within the temperature range of 30 to 90 °C to evaluate the effect of Zn²⁺ ion on dielectric constant and dielectric loss of ADP crystal. The thermal stability of the grown crystal has been investigated within the temperature range of 40–500 °C. The application of developed Zn-ADP crystal for photonic devices has been discussed in vision of obtained results.     

Experimental and theoretical studies on bis(glycine) lithium nitrate (BGLiN): A physico-chemical approach

Good quality and bulk size single crystal (size: 20×13×8 mm³) of bis(glycine) lithium nitrate (BGLiN) was grown by a slow evaporation solution technique from the aqueous solutions at constant temperature i.e. 27 °C using synthesized materials. Crystal system and lattice parameters were determined by single crystals as well as powder X-ray diffraction analysis. The lattice parameters of the titled compound are a=10.0223 Å, b=5.0343 Å, c=17.0510 Å, and V=860.312 Å³ and it crystallized in an orthorhombic system with space group Pca2₁ obtained by single crystal XRD. Elemental composition was confirmed by energy dispersive X-ray spectroscopic analysis. Optical absorption spectrum was recorded and various optical parameters such as optical transmission (~60%), and optical band gap (4.998 eV) were calculated. Photoluminescence study shows that the grown crystal is free from major defects. Crystalline perfection of the grown crystal was assessed and found good. Ground state optimized geometry has been obtained by using DFT with 6-31G(d,p) basis set. HOMO and LUMO energy gap was found to be 6.01 eV and dipole moment was 1.65 D.     

Crystal growth,optical and thermal studies of nonlinear optical γ-glycine single crystal grown from lithium nitrate

Single crystals of the nonlinear material γ-glycine have been grown in the presence of lithium nitrate by slow-evaporation method. Structural characterization of the grown crystals was carried out by powder and single crystal X-ray diffraction (XRD) methods and it is observed that the samples crystallize in hexagonal system with non-centrosymmetric space groups. The modes of vibrations of different molecular groups present in glycine have been identified by spectral analyses. UV–visible transmittance study was performed to analyze optical transparency of γ-glycine crystals and found that the crystal was transparent in the entire visible-NIR region. Second harmonic generation (SHG) conversion efficiency has been estimated as 62 mV and the output power by the crystal was 1.72 times that of potassium dihydrogen phosphate (KDP) crystal. The thermal stability and decomposition of the sample have been studied by thermal analysis and it is observed that the γ-glycine crystal have good thermal stability.     

Efficient cw violet-light generation in a ring cavity with a periodically poled KTP

In this work, we experimentally demonstrate an efficient cw second harmonic generation (SHG) at 780 nm wavelength with a first-order type-I phase matching periodically poled KTP (PPKTP) crystal in a ring cavity, the wavelength corresponds to the D₂ line of Rb atom transition. The fundamental laser used is a grating-stabilized external cavity diode laser and its frequency is precisely locked to Rb atom transition frequency using the saturated absorption technique. About maximal 6.9 mW UV radiation of 390 nm with a net conversion of 9.5% at an input mode-matched power of 73 mW is generated with one crystal, and about maximal 8.8 mW with the net conversion of 12% is obtained with another crystal; the powers in stable operation are about 1.7 mW and 3.4 mW, respectively. This is, to our best knowledge, the first SHG experiment at 780 nm wavelength with the PPKTP in a ring cavity.     

Growth,structural, optical and mechanical studies on acid mixed glycine metal salt (GABN) crystal as potential NLO material

Transparent crystals of α-glycine with ammonium nitrate and barium nitrate (GABN) have been grown from aqueous solution by slow evaporation technique at room temperature. Crystals of size 11 × 7 × 4 mm³ have been obtained in about 3–4 weeks time. The solubility of GABN has been determined in water. The grown crystal belongs to orthorhombic system with cell parameters a = 7.317 A.U, b = 12.154 A.U and c = 5.468 A.U with a unit cell volume 486.35 (A.U)³. The presence of chemical components/groups has been identified by CHN, EDAX and NMR analysis. Comparative IR and Raman studies indicate a molecule with a lack of centre of symmetry. A wide transparency window useful for optoelectronic applications is indicated by the UV Studies. Using a Nd-YAG laser (1064 nm), the optical second harmonic generation (SHG) conversion efficiency of GABN is found to be 1.406 times of that of standard KDP. On exposure to light the GABN crystals are found to exhibit negative photoconductivity. I–V characteristics, SEM studies, dielectrics studies, and Vickers micro hardness measurement have been carried out.     

Color center of YAlO3 with cation vacancies

High quality pure YAlO₃ crystal with dimension of Φ 30 × 50 mm² was grown by Czochralski technique. UV irradiation and air annealing bring additional absorption in the region 200–800 nm. The absorption spectra of perfect YAlO₃ and YAlO₃ containing cation vacancy (aluminium vacancy and yttrium vacancy) were calculated using density functional theory code CASTEP. Comparison of the simulated absorption spectra with the experimental absorption spectra of YAlO₃ after UV irradiation and air annealing treatments shows that cation vacancies are responsible for part of the coloration on YAlO₃ crystal.     

Synthesis and characterization of sulfur-containing polyacetylene derivative: Synthesis of poly(phenyl propargyl sulfide) and its electro-optical properties

Sulfur-containing conjugated polymer was synthesized by the polymerization of phenyl propargyl sulfide by transition metal catalysts such as PdCl₂, RuCl₃, (NBD)PdCl₂, WCl₆, and MoCl₅. The polymerization proceeded well in homogeneous manner to give a moderate yield of polymer. The chemical structure of poly(phenyl propargyl sulfide) was characterized by NMR (¹H–, ¹³C–), IR, and UV–visible spectroscopy, and elemental analysis to have the conjugated polymer backbone with the designed moieties. The FT-IR spectra of the polymer did not show the acetylenic CC bond stretching (2119 cm⁻¹) and acetylenic C–H bond stretching (3293 cm⁻¹) frequencies of the monomer. The thin polymer film exhibited reversible electrochemical behaviors between the doping and undoping peaks. Poly(phenyl propargyl sulfide) showed the characteristic UV–visible absorption band at 360 nm and blue PL spectrum at 460 nm, corresponding to the photon energy of 2.70 eV. The energy band gap of poly(PPS) was estimated to be 2.77 eV from the analysis of the absorption edge.     

Concentration quenching of Eu2+ in a thermal-stable yellow phosphor Ca2BO3Cl:Eu2+ for LED application

A piece-shaped phosphor Ca₂BO₃Cl: Eu²⁺ was synthesized by solid-state reaction method. This phosphor exhibited wide absorption in ultra-violet and visible range, and bright yellow emission band centering at 570 nm. The concentration quenching mechanism was verified to be a dipole–dipole interaction, and its critical transfer distance was about 17 Å by both calculated crystal structural method and experimental spectral method. This phosphor has a good thermal stability with a quenching temperature (T_1/2) of 200 °C. Yellow and white LEDs were fabricated with this phosphor and near UV chips, and the yellow LED has a high color purity of 97.0% and promising current tolerant property, while the white LED shows a luminous efficiency of 11.68 lm/W.     

Synthesis,growth and characterization of an organometallic complex tri-allylthiourea cadmium bromide single crystals

Allylthiourea cadmium bromide (ATCB) is a promising organometallic second order nonlinear optical material. ATCB was synthesized in Millipore water and single crystals of ATCB were grown by isothermal solvent evaporation as well as by conventional temperature lowering methods. Crystal structure of the as grown ATCB was analyzed by single crystal X-ray diffraction and also by powder X-ray diffraction pattern. Structural perfection of the as grown single crystal was studied through multicrystal X-ray diffraction analysis. The nature of co-ordination and the functional groups present were investigated by the Fourier transform infrared spectrum. The melting point of the crystal was studied through differential scanning calorimetric analysis. The optical absorption spectrum of the as grown crystal exhibits the lower cut-off (295 nm) with the wide transparent UV–VIS–NIR wave band. The SHG property was identified by Kurt’z powder technique. The linear refractive index of the as grown crystal was measured for different laser wavelengths. The reverse indentation size effect for the as grown crystal was confirmed from the mechanical studies. Growth mechanism and surface features of the as grown single crystals were analyzed by chemical etching analysis.     

Synthesis,growth and characterization of a novel semiorganic nonlinear optical single crystal: l-Asparagine cadmium chloride monohydrate

The semiorganic single crystal of l-asparagine cadmium chloride monohydrate was grown by slow evaporation solution growth technique at room temperature. The presence of various functional groups has been identified by using FT IR spectral analysis ranging between 4000 and 400 cm^?1. Chemical composition of the synthesized material was confirmed by elemental analysis. The crystalline nature of new crystal was confirmed by powder XRD pattern. The UV–vis–NIR spectroscopic study revealed that the grown crystal has good optical transmittance. The dielectric constant has been carried out over a frequency range from 100 Hz to 1 MHz. The mechanical strength was studied using Vicker's microhardness tester.     

Absorption,luminescence, and electron paramagnetic resonance of molybdenum ions in CdWO4

A single crystal of cadmium tungstate (CdWO₄) containing approximately 200 ppm of molybdenum was grown by the Czochralski method and then characterized in a series of optical absorption, photoluminescence (PL), photoluminescence excitation (PLE), and electron paramagnetic resonance (EPR) experiments. The Mo⁶⁺ ions substitute for W⁶⁺ ions and serve as recombination sites for electrons and holes when the crystal is exposed to ionizing radiation. A charge-transfer absorption band for the Mo⁶⁺ ions was observed near 320 nm at 10 K. The PL experiments, performed at low temperature with 325 nm excitation, showed a Mo-associated emission peaking near 680 nm. A direct correlation of the 680 nm emission and the 320 nm absorption band was established by the PLE data. When these doped CdWO₄ crystals are exposed at low temperature either to light that is near or above the band gap or to X-rays, the Mo⁶⁺ ions can trap an electron and form stable Mo⁵⁺ ions. The EPR spectrum of the Mo⁵⁺ ions was observed at temperatures near 15 K, and a complete set of parameters describing the g matrix was obtained from an angular dependence study.