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Summary: Recently, lead and tellurium‐free GeSe chalcogenide‐based thermoelectric materials have been considered as an alternative for PbTe and GeTe because of their nontoxic and attractive properties. However, the reports on thermoelectric properties of GeSe are very limited with low power factor values. Herein, we report the effect of Cu substitution on mixed phase formation and thermoelectric performance of Ge1−xCuxSe (0.0 ≤ x ≤ 0.4) samples. In the prepared samples, the multiphases of orthorhombic/Imm2 Cu2GeSe3, cubic/Fm3m Cu2Se, hexagonal/P63mc CuSe, hexagonal/P63/mmc Cu8GeSe6, and orthorhombic/Pnnm CuSe2 were observed, due to incorporation of Cu in GeSe as confirmed by X‐ray diffraction analysis. The electrical resistivity of the samples decreased with x values due to the formation of Cu‐rich phases. Moreover, the mobility of GeSe increased by one order through Cu substitution resulting from the percolation effect in the sample with multiphases. A high‐power factor of 720 μW/K2m was achieved at 500 K for the Ge0.6Cu0.4Se samples with thermal conductivity (κL) of 1.47 Wm−1κ−1 at the same temperature which resulted in a high figure of merit (ZT) ~ 0.26, due to Cu‐rich multiphases in the sample. [ABSTRACT FROM AUTHOR]

In the present work, synthesis of CoMnO electrode material through a newly adopted hydrothermal method was achieved and reported. The synthesized material was subjected to various physico-chemical properties to analyze the suitability of the material for the super capacitor applications. The structure of the title compound was confirmed by powder X-ray diffraction studies. Fourier transform infrared spectroscopy confirms the various functional groups associated with the material. Optical and surface analysis was studied by using UV-Visible spectroscopy and field emission scanning electron microscopy. The electrochemical properties of modified electrode CoMnO were investigated using cyclic voltammetry, galvanostatic charge-discharge, cycle stability and electrochemical impedance spectroscopy in electrochemical workstation. Based on the electrochemical properties, the electrode material reveals the ideal capacitance behaviour with high capacitance of 700 F/g at the sweep rate of 5 mV/s in 3 M KCL aqueous electrolyte solution. The remarkable electrochemical performance undoubtedly makes CoMnO as the promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Graphene-ceria (CeO2G) nanocomposites were prepared by using a low-temperature solution process with different weight percentages of graphene, and their electrochemical properties were investigated. Structural properties of the nanocomposites were studied by X-ray diffraction, Raman spectroscopy, and FTIR spectral analyses. FE-SEM and HRTEM images revealed a “wrinkled paper”-like morphology of the prepared composites. Elemental mapping images were recorded by using the FE-EPMA technique. XPS analyses revealed the binding states of different elements present in the composites. The composite with 5% graphene displayed a specific capacitance of 110 F g−1, according to cyclic voltammetric studies, which is higher than that observed for pure CeO2 (75 F g−1). The significant increase in the specific capacitance suggests that the CeO2G is a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Different concentrations of europium (Eu), cerium (Ce) doped and co-doped ZnO:Eu (1%), Ce (1%) nanorods were successfully synthesized by chemical method using Polyvinylpyrrolidone as a surfactant. Crystalline phase, morphology, functional groups, optical absorption, emission and thermal properties of prepared samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), Scanning electron microscopy (SEM), High-resolution transmission electron microscopy (HR-TEM), Fourier transform infra-red (FT-IR), UV–visible, Photoluminescence (PL) spectrophotometer and thermogravimetry (TG) and differential thermal analysis (DTA) analysis. The XRD study showed high crystalline nature of the products with nanoscale regime. Optical study showed shifting the absorption and emission spectra toward higher wavelength side when increasing the doping concentrations. Mainly, this is first time observed a red emission peak at 660 nm for Ce (3%) doped ZnO. Additionally, co-doped ZnO:Eu (1%), Ce (1%) nanorods were synthesized and studied their optical properties. This work demonstrates that simply modified their optical absorption and emission of ZnO by introducing rare earth ions can be used as an effective electrode material in solar cell applications, optoelectronic devices and photocatalysis analysis. [ABSTRACT FROM AUTHOR]

Ceria and gadolinium (Gd) doped ceria nanowires have been synthesised by hydrothermal technique with mild reaction conditions. The structure and morphology of as-prepared nanowires were studied by X-ray diffraction and field emission scanning electron microscopy (FE-SEM) techniques. The FE-SEM analysis revealed the formation of nanowires with an average diameter of 10–15 nm. Atomic force microscopy (AFM) analysis for the annealed samples confirms the existence of well defined nanorods of 120–150 nm diameter and 1–1.3 μm length. Fluorescence and diffuse reflectance spectroscopy techniques have been used to study the optical properties of the prepared nanowires. The observed red shift in the ultraviolet–visible absorption spectra confirmed the promoted electron–phonon interaction in CeO2and Gd:CeO2nanowires compared to bulk structures. The prepared nanowires/rods were thermally stable at up to 350 °C, as revealed by thermogravimetric analysis. The electrical properties were studied by cyclic voltammetry (CV) and impedance spectroscopy. The CV results demonstrated that Gd:CeO2exhibited a higher electro-oxidation than CeO2nanowires. [ABSTRACT FROM AUTHOR]

Abstract: A facile co-precipitation route has been employed to synthesize cerium oxide (CeO2) nanoparticles using cationic surfactant (tetradecyltrimethyl ammonium bromide, C14TAB) and cerium nitrate hexahydrate at room temperature. X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), selected area electron diffraction (SAED), fourier transform infrared spectroscopy (FT-IR), UV–vis spectrophotometer and photoluminescence spectroscopy (PL) were employed to characterize the as-prepared sample. The XRD pattern showed cubic fluorite structure of CeO2 without any impurity peaks, revealing high purity of the sample. The lattice strain experienced by the sample was analyzed using Williamson-Hall plot. FTIR studies confirmed the presence of C14TAB on the CeO2 nanoparticles. TEM revealed that the as-prepared CeO2 sample consists of uniform particles with particle size of 10nm. The red shift phenomenon was observed in UV–vis spectrum, which was further supported by PL studies. [Copyright &y& Elsevier]

BaTiO nanoparticles were prepared by high energy ball milling and subjected to conventional and microwave post sintering at 1,000 °C. From the powder X-ray diffraction results, the synthesized material exhibits strong tetragonality with large c/a ratio. Scanning electron microscope results show the formation of tetragonal shaped BaTiO crystals in the nanometer scale and a significant reduction in the particle size for the microwave sintered sample. The reduced d-spacing of 1.741 Å with high crystallinity for the microwave sintered material is revealed by high resolution transmission electron microscopy analysis. Ultraviolet-visible spectroscopy studies confirm the higher optical band gap (E) of 4.157 eV for the microwave sintered sample. Microwave sintered sample shows a very high dielectric constant of ε = 4,445 with a low dielectric loss as tan δ = 0.0961. Microwave sintered sample exhibit a high polarization maximum of 73 μC/mm with reduced coercivity to be 0.293 kV/mm. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a facile synthesis of 1D-rodlike Yttrium manganite (YMnO3) was reported. YMnO3 nanorods were successfully prepared via a hydrothermal process. The prepared sample was subjected to structural, morphological and magnetic property studies. The XRD pattern confirmed that the prepared sample is phase pure with hexagonal structure. HRSEM, HRTEM and AFM images revealed that the sample contains uniform nanorods with average diameter of 100nm and length in several micrometers. MFM image shows a magnetic distribution in the rods. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curve shows an anti-ferromagnetic to paramagnetic transition TN (Neel temperature) at ~80K in the temperature range from 20 to 300K which was further confirmed by magnetic hysteresis loops. [Copyright &y& Elsevier]

Single crystals of lead zinc niobate-lead titanate (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 for x = 8% and 9% have been grown by flux method using Lead Oxide (PbO) as flux. Low scan rate XRD has been carried out to investigate on the structural influence of the compositional variations in the grown crystals. Transmission spectra in the range of UV-Vis-Near IR and mid IR regions have been carried out to understand the distortions caused in the BO6 octahedral lattice. Morphological aspects of as-grown PZN-PT crystals have also been investigated. Dielectric measurements clearly explained the dependence of Tc and diffusiveness with PT content. The values of Pr and Ecobtained from P-E loops suggest the presence of ordered domain state in these PZN-PT single crystals. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Nearly perfect single crystals of l-histidine hydrochloride monohydrate have been grown from the solution prepared from the mixture of l-histidine and hydrochloric acid using slow evaporation solution growth technique. Single crystal X-ray diffraction analysis, High resolution X-ray diffraction analysis, fourier transform infrared and FT-Raman analyzes were employed for structural characterization. Linear and nonlinear optical properties have been studied by UV–Vis transmission spectrum and Kurtz Perry technique respectively. The refractive index, redox behavior and hardness of the grown crystal have been found by suitable methods. Thermogravimetric, differential thermal analysis were employed to characterize the as-grown crystals. The second harmonic generation conversion efficiency of the grown crystal and other properties show the suitability of the grown crystal for frequency conversion applications. [Copyright &y& Elsevier]

A semi-organic nonlinear optical L-proline dimercuricchloride (LPDMC) material has been synthesized. LPDMC single crystals were grown from aqueous solution by a slow cooling method. Good quality single crystals of size 19×6×3 mm have been grown over a period of 3 weeks. The grown crystals have been subjected to single crystal X-ray diffraction analysis to determine the cell parameters. The title compound crystallizes in the triclinic system with a noncentrosymmetric space group P1 and with unit-cell parameters a=7.2742(4) Å, b=9.4472(5) Å, c=10.4767(6) Å, α=108.621(3), β=107.260(2), γ=97.353(2) and volume=631.51(6) Å. Optical and dielectric properties of the crystals have been studied. The thermal stability of the crystals was determined by thermogravimetric analysis/differential thermal analysis. The second harmonic generation efficiency of the crystals was obtained by the classical powder technique using a Nd:YAG laser and it is found to be 2.5 times that of potassium dihydrogen phosphate. [ABSTRACT FROM AUTHOR]

Highly monodispersed CdS nanoparticles using polyvinyl pyrrolidone (PVP) as the capping agent were synthesised by chemical coprecipitation method. The surface-modified cadmium sulfide nanoparticles were found to be remarkably stable. In the presence of PVP, cubic phase with small grain size of CdS were observed in XRD. The peaks were identified to originate from (111), (220) and (311) planes of CdS, respectively. The crystallite size of the synthesised CdS nanoparticles was about 3 nm calculated from the (111) plane of XRD pattern and it was also confirmed through HRTEM. Morphology and elemental mapping of the synthesised nanoparticles were studied by SEM and EDX analyses. Increase in the band gap with decrease in the particle size was observed from the reflectance mode UV spectrum, which confirms the quantum confinement effect. From the photoluminescence studies, enhanced near-band-edge blue light emission and significantly reduced defect-related green emission were observed. Longitudinal optical (LO) phonon modes, corresponds to pure CdS were observed in Raman spectrum. [ABSTRACT FROM AUTHOR]

Cadmium sulfide nanoparticles have been synthesized by hydrothermal method using cadmium acetate, thiosemicarbazide, and sodium hydroxide as precursors with hexamethylene tetramine as the surfactant. From the X-ray diffraction analysis, it is observed that synthesized CdS nanoparticles show cubic phase. The presence of HMTA in CdS was confirmed by FT-IR analysis. The bandgap value of CdS nanostructure has been estimated by DRS-UV-Visible spectral analysis. The formation of flower-like nanoclusters was observed using scanning electron microscopy (SEM). The application of CdS nanoparticles in photocatalytic degradation was also studied. [ABSTRACT FROM AUTHOR]

Cerium-doped ZnS nanoparticles have been synthesized through hydrothermal method. The nanoparticles were stabilized using hexamethylenetetramine (HMTA) as surfactant in aqueous solution. The average particle size of the prepared samples is about 2 nm. The structure of the as-prepared ZnS nanoparticles is cubic (zinc blende) as demonstrated by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The UV-Vis absorption spectra of the prepared ZnS nanoparticles show a considerable blueshift in the absorption band edge compared to bulk ZnS indicating a strong quantum confinement effect. Formation of HMTA-capped ZnS nanoparticles was confirmed by FTIR studies. Photoluminescence studies showed that the relative emission intensity of Ce3+-doped ZnS nanoparticles is higher than that of undoped ZnS nanoparticles, which is due to the enhancement of radiative recombination in the luminescence process. The PL spectra showed two emission peaks at around 420 nm and 442 nm, which may be attributed to deep-trap emission or defect-related emission of ZnS and presence of various surface states. [ABSTRACT FROM AUTHOR]

Cobalt-doped cadmium sulphide (CdS) nanocrystals (NCs) were synthesized with three different cobalt concentrations by aqueous chemical coprecipitation method. Dopant incorporation was recognised using X-ray diffraction (XRD) analysis with a shift in the diffraction peaks and compression in the lattice. The size and crystallinity of the cobalt-doped CdS NCs were studied by high resolution transmission electron microscopy (HRTEM). The blue shift in the spectra and the band gap value of Co-doped CdS NCs was estimated using reflectance UV spectrophotometer. Variation in the luminescence properties was studied by fluorescence spectroscopy. The change in the optical properties supports the Co incorporation in the CdS NCs. The BET measurement revealed that the powders had a relatively high specific surface area of 131.30, 106.93 and 102.04 m/g for 2, 4 and 6% Co:CdS, respectively. Room temperature magnetisation was studied using vibrating sample magnetometer for both 4 and 6% cobalt-doped CdS NCs, which revealed a weak ferromagnetic signal and strong ferromagnetic hysteresis respectively. [ABSTRACT FROM AUTHOR]

A new non-linear optical mixed crystal of L-arginine hydrochlorofluoride monohydrate (LAHClF) has been grown by temperature lowering solution growth technique. The single crystal X-ray diffraction studies show that the LAHClF belongs to monoclinic crystal system. The optical transmittance of the crystal was studied by UV–Visible–NIR spectroscopy. Fourier transform infrared spectroscopy and thermal analysis were performed to study the molecular vibrations and thermal behavior of the crystals, respectively. The second harmonic generation intensity and laser damage threshold of the LAHClF crystal were measured. The mechanical strength of the material was determined by the Vickers hardness method. [ABSTRACT FROM AUTHOR]

Selenium sulfide (SeS2) passivated GaAs is bonded with silicon substrate at 350°C. X-ray diffraction (XRD) analysis shows the formation of Ga–Se phase in the passivation process. From the XRD analysis, β-Ga2Se3 peak is also observed for the chemical and thermal stability of GaAs at 350°C. Scanning electron microscopy (SEM) shows smooth surface morphology for SeS2 treatment time of 10 s. Elemental analysis shows that 10 s passivation treatment is optimal for adhesive wafer bonding without applying any weight and pressure at different regions (GaAs and SeS2). XRD, SEM and energy dispersive X-ray results confirm that 10 s of passivation treatment is essential for high stability of adhesive wafer bonding of GaAs and Si. [Copyright &y& Elsevier]

Green synthesis techniques are developing as more simplistic and eco-friendly approach for the synthesis of metal nanoparticles compared to chemical reduction methods. Herein we report Synthesis of highly stable silver nanoparticles using Mirabillis jalapa seed extract as a reducing and capping agent. The as-prepared silver nanoparticles were characterized by UV–vis spectroscopy (UV–vis) to confirm the formation of silver nanoparticles by its characteristic surface plasmon resonance peak observed at 420 nm. The Powder X-ray diffraction (P-XRD) revealed the structure and crystalline nature of synthesized silver nanoparticles, The Fourier transform infra-red spectroscopic (FT-IR) revealed the presence of the biomolecules in the extract that acted as reducing as well stabilizing agent. The high resolution transmission electron microscopic (HRTEM) images divulged that the synthesized silver nanoparticles were spherical in shape and poly dispersed. The energy dispersive X-ray diffraction (EDX) profile revealed the elements present in the as-synthesized colloidal silver nanoparticles and its percentages. The Zeta potential measured for silver nanoparticles evidenced that the prepared silver nanoparticles owned high stability in room temperature itself. The as-synthesized silver nanoparticles (AgNPs) in colloidal form were showed good antimicrobial effects and it's were found to exhibit third order optical nonlinearity as studied by Z-scan technique using 532 nm Nd:YAG (SHG) CW laser beam (COHERENT—Compass 215 M-50 diode pumped) output as source. The negative nonlinearity observed was well utilized for the study of optical limiting behavior of the silver nanoparticles. [ABSTRACT FROM AUTHOR]

A potential organic urea maleic acid (UMA) was synthesized and single crystals were grown at room temperature by slow evaporation and seed rotation methods. The grown crystal has been subjected to single crystal XRD analysis and found to have been crystallized in a noncentrosymmetric monoclinic crystal system with Cc as space group. The High resolution X-ray diffraction analysis revealed that the specimen is free from structural grain boundaries. The transparency of the grown crystal was confirmed by optical absorption and transmittance spectra with lower cut-off wavelength of 285 nm. The microhardness test was carried out on different planes to study the load dependent hardness values. The dislocation density of the UMA crystal was estimated from the etching studies. The dielectric permittivity and dielectric loss of the grown crystal was carried out as a function of frequency for different temperatures along three crystallographic axes. Thermal properties of UMA crystals were studied by TG-DTA analysis and it is stable upto 112 °C. The laser induced surface damage threshold of the grown crystal was measured using Nd: YAG laser. The birefringence of the crystal measured in the visible region was found to vary with the wavelength. The particle size dependent SHG of the sample was measured with different input energies by Kurtz's powder method using Nd:YAG laser. [ABSTRACT FROM AUTHOR]

Abstract: A novel nonlinear optical metal-organic, Bis thiourea antimony tri bromide (BTAB) single crystal was grown from aqueous solution by slow cooling technique. The grown crystals have been characterized by different techniques to study the structural, thermal, mechanical, linear and nonlinear optical properties. The powder SHG efficiency was found to be 2.5 times higher than that of the KDP crystal. BTAB is a biaxial and optically positive crystal. The birefringence value of BTAB crystal was found to be 0.112 at the wavelength of 550nm for a sample thickness of 0.11mm.The BTAB crystal has refractive indices values of nα =1.539, nβ =1.559 and nγ =1.967. BTAB crystallizes in orthorhombic system and the complex formation is established by metal–sulfur bond. BTAB has good optical transmission in the entire visible region, so that it is found to be potential material for nonlinear frequency conversion. [Copyright &y& Elsevier]

Abstract: Single crystals of triglycine sulfate (TGS) with l-glutamine and l-methionine were grown in aqueous solutions by a slow cooling method. The grown crystals were subjected to single crystal and powder X-ray diffraction studies to identify the morphology and the structure. FTIR and UV–visible spectra reveal the functional group identification and optical property of the grown crystals. The dielectric studies were carried out to identify the phase transition temperature and to find the dielectric constant. Microhardness studies have been carried out to assess the mechanical property. P-E hysteresis studies were carried out to find the values of spontaneous polarization and coercive field for doped TGS crystals. [Copyright &y& Elsevier]

Growth of SeS and SeSnS2 micro crystals by slow evaporation technique was established, respectively, from the solution of selenium sulfide (SeS2), and selinium sulfide (SeS2) and tin sulfide (SnS2) mixtures in CS2. The crystals were characterized by XRD, SEM, IR and UV absorption techniques. SeS phase was identified by powder X-ray diffraction (XRD) studies. Rod-like and rod-like platy morphologies were established for SeS and SeSnS2, respectively, by SEM. IR analysis of SeSnS2 micro crystal revealed disappearance of most of the hyperfine structures in the absorption region of SeS between 450 and 500 cm−1 suggesting tin doping. UV-absorption measurement showed the shift in cut-off frequency of SeS from 300 to 525 nm confirming once again the entry of SeS into SnS2. [Copyright &y& Elsevier]

Single crystal growth of nonlinear optical L-arginine acetate is reported. Low temperature solution growth was employed for the growth of bulk single crystals. The cell parameters were determined by powder X-ray diffraction analysis. FTIR analysis was used to confirm the presence of various functional groups in the grown crystals. Thermal analysis was performed to study the thermal stability of the grown crystals. The crystals possess lower UV-cut off wavelength at 240 nm as confirmed by the transmittance studies. Kurtz powder SHG measurement confirms the NLO property of the grown crystal. Laser damage threshold studies were also performed on the grown crystals. [Copyright &y& Elsevier]

Influence of Mn substitution on bulk textured Bi2Sr2Ca(Cu1−xMnx)2O8+δ crystals grown by the immersed heater floating zone technique has been studied for the first time. The properties of pure and Mn doped Bi-2212 crystals are compared. X-ray diffraction studies show that the texturing percentage and the c-lattice parameter decrease with increase in Mn concentration. The scanning electron microscope study reveals the cellular growth pattern for x=0.4 Mn concentration. The superconducting transition temperature decreases on increasing Mn concentration. [Copyright &y& Elsevier]

Abstract: Cerium doped cadmium sulfide nanoparticles (Ce:CdS) were synthesized by coprecipitation method with three different concentrations of cerium (1, 2 and 3mol%). Powder X-ray diffraction pattern reveals the formation of cadmium sulfide nanoparticles with hexagonal (wurtzite) structure. It was observed that the presence of ceria does not alter the structure of CdS. Average particle size was measured to be ~3nm. Reflectance spectra illustrate band-to-band absorption at 453, 500 and 507nm respectively for 1, 2 and 3% Ce doped CdS nanoparticles. The presence of cerium was confirmed by EDX and ICP-OES analyses. The effect of dopant concentration on the photoluminescence (PL) intensity has also been studied. XRD and PL analyses demonstrate the Ce3+ ions uniformly substitute Cd2+ sites or interstitial sites in CdS lattice which influences the optical properties. Increase in the concentration of cerium slightly shifts the absorption and emission toward higher wavelength. Particle size and the crystallinity of Ce:CdS NPs were confirmed through HRTEM and SAED patterns. [Copyright &y& Elsevier]

Facile synthesis of graphene–Nb 2 O 5 composite has been reported. Graphene oxide was prepared by the modified Hummer's method. The metal oxide (Nb 2 O 5 ) was introduced to the graphene to form the composite by the hydrothermal method. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared (FTIR) and thermo gravimetric analysis (TGA). SEM and TEM results revealed that the metal oxide particles are uniformly dispersed on the surface of thin sheets of well-defined multilayered graphene structure. Thermal stability of the graphene metal oxide nanocomposites was also investigated. The CV measurements reveal a significant enhancement in the specific capacitance reaching 321 Fg −1 at a scan rate of 10 mV s −1 . With promising electrochemical characteristics, Nb 2 O 5 decorated graphene nanocomposite are explored as potential electrode material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ni doped CdS nanoparticles are synthesized by chemical precipitation method. [•] X-ray diffractogram confirms the formation of CdS with dopant. [•] FTIR spectrum reveals that the nanosamples are encapsulated by DETA. [•] The UV-VIS absorption spectra shows strong blue shift. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two different crystals have grown in a single solution made up of l-histidine and HCl. [•] Structural optical and thermal properties were studied and compared. [•] l-Histidine possesses better properties than l-histidine hydrochloride monohydrate. [Copyright &y& Elsevier]

Single crystals of nonlinear optical bis d-phenyl glycinium sulphate monohydrate (BD-PGSMH) are grown by slow evaporation technique from aqueous solution at room temperature. Optically transparent crystals of dimensions up to 32 × 30 × 2 mm3 are obtained within a period of 30 days. Single crystal X-ray diffraction analysis and powder X-ray diffraction analysis confirm that the crystal belongs to monoclinic system with the space group P21. The crystal is subjected to the characterizations such as Fourier transform infrared (FTIR) analysis, UV–visible–NIR optical absorption spectral studies, thermo gravimetric and differential thermal analysis (TGA/DTA) and dielectric measurements. The electrical conductivity variation is also studied for different temperatures. The second harmonic generation (SHG) property in the crystal is confirmed by using Kurtz-powder technique and the SHG efficiency is found to be 0.8 times greater than that of KDP crystal. [ABSTRACT FROM AUTHOR]

Abstract: Picolinium picrate monohydrate (PPM), an organic optical material, was synthesized and single crystals were grown by slow evaporation solution technique. The cell parameters of PPM were confirmed by single crystal X-ray diffraction analysis. The PPM crystals were subjected to FT-IR spectral analyses to confirm the synthesized compound. UV–vis–NIR spectral studies revealed that the optical transparency window of PPM crystal spreads over in the visible and NIR (480–900nm) regions. From the transmittance data, the optical band gap as function of photon energy was estimated. The microhardness studies were carried out on PPM crystal. The laser damage threshold of PPM crystal was measured using Nd:YAG laser. [Copyright &y& Elsevier]

Abstract: Picolinium maleate (PM), an organic material has been synthesised and single crystals were grown by slow evaporation technique. The structure of the grown crystal was elucidated by using single crystal X-ray diffraction analysis. PM crystal belongs to the monoclinic crystallographic system with space group P21/c. The crystalline perfection of the grown crystals was analyzed by high-resolution X-ray diffraction rocking curve measurements. The presence of functional groups in PM was identified by FTIR and FT-NMR spectral analyses. Thermal behaviour and stability of picolinium maleate were studied by TGA/DTA analyses. UV–Vis spectral studies reveal that PM crystals are transparent in the wavelength region 327–1100nm. The laser damage threshold value of PM crystal was found to be 4.3GW/cm2 using Nd:YAG laser. The Kurtz and Perry powder second harmonic generation technique confirms the nonlinear optical property of the grown crystal. [Copyright &y& Elsevier]

Abstract: Synthesis and growth of a novel organic nonlinear optical (NLO) crystal of 4-aminopyridinium maleate (4APM) in larger size by the slow evaporation solution growth technique are reported. Single crystal and powder X-ray diffraction analyses reveal that 4APM crystallizes in monoclinic system with space group P21 with cell parameters a =8.140(4)Å, b =5.457(5)Å, c =10.926(10)Å and volume=481.4(7)Å3. The grown crystal has been characterized by Fourier transform infrared and UV–visible spectral analyses. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) have been carried out to study its thermal properties. Dielectric measurements have been carried out to study the distribution of charges within the crystal. The mechanical strength of the crystal has been studied by using Vickers’ microhardness test. The etching studies have been carried out on the grown crystal. The Kurtz and Perry powder SHG technique confirms the NLO property of the grown crystal and the SHG efficiency of 4APM was found to be 4.8 times greater than that of KDP crystal. [Copyright &y& Elsevier]

Abstract: To study the improved characteristics of l-arginine phosphate monohydrate (LAP) crystals, amino acids mixed LAP crystals have been grown by slow cooling method. Amino acids like glycine, l-alanine, and l-valine have been selected for doping. Optical quality bulk crystals have been harvested after a typical growth period of about twenty days. The effect of amino acids in the crystal lattice and molecular vibrational frequencies of various functional groups in the crystals have been studied using X-ray powder diffraction and Fourier Transform infrared (FTIR) analyses respectively. Thermal behavior of the amino acids mixed LAP crystals have been studied from the TG and DTG analyses. High-resolution X-ray diffraction studies have been carried out to find the crystalline nature. Optical transmission studies have been carried out by UV–vis spectrophotometer. The cut off wavelength is below 240nm for the grown crystals. [Copyright &y& Elsevier]

Abstract: Single crystals of semi-organic l-histidine hydrobromide have been grown by slow evaporation technique from a mixture of l-histidine and hydrobromic acid in aqueous solution at ambient temperature. From high-resolution X-ray diffraction analysis, the crystalline perfection of the grown crystal has been studied. Single crystal X-ray diffraction analyses, Nuclear Magnetic Resonance spectral analysis, Thermo-Gravimetry (TG), Differential Thermal Analysis (DTA) and hardness test have been employed to characterize the as-grown crystals. The UV cutoff wavelength of the grown crystal is below 300nm and has a wide transparency window, which is suitable for second harmonic generation of laser in the blue region. Nonlinear optical characteristics have been studied using Q switched Nd:YAG laser (λ=1064nm). The second harmonic generation conversion efficiency of the grown crystals confirms their suitability for frequency conversion applications. [Copyright &y& Elsevier]

Abstract: Influence of Pr doping on the structural, optical properties of ZnO nanorods prepared through an aqueous solution route has been made. The wurtzite crystal structure of the host specimen was studied to be unaltered on Pr substitution into the host lattice, from the X-ray diffraction measurements. The lattice constants for the Pr-doped ZnO nanorods were observed to increase slightly with respect to the Pr composition. The morphology and chemical composition of the nanorods were studied using field emission scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy and inductive coupled plasma (ICP) techniques. The high resolution transmission electron microscopy and selected area electron diffraction pattern revealed the highly crystalline nature of Pr-doped ZnO nanorods. Zn–O bonding studied from the FT-IR spectroscopy has been observed to shift towards the lower wavenumbers on Pr incorporation. The crystallinity of the nanorods has been additionally studied using Raman spectroscopy, with the sharp peak observed at 438cm−1. A red shift in the NBE emission has been observed at 394nm on Pr doping, along with a broad visible emission in the luminescence spectra. [ABSTRACT FROM AUTHOR]

Abstract: Pure and transition metal ion (Mn and Co)-doped SnO2 nanoparticles were synthesized using a simple chemical precipitation method. Transition metal ions (Mn and Co) of 1, 3 and 5mol% were doped in order to study the influence of structural and optical properties. The structural, chemical and optical properties of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and UV–vis spectroscopy techniques. The SnO2 crystallites were found to exhibit tetragonal rutile structure with lattice parameters, revealing that the metal ions get substituted in the SnO2 lattice. It is observed that the peak position (110) get shifted to lower angles by increasing the dopant concentration. Hence the lattice parameters (a and c) and the cell volume get decreased. The SEM photograph shows that the grain size of pure SnO2 is larger than that of the metal-doped SnO2 indicating grain growth upon doping. TEM photograph revels that by increasing the content of metal ions, average grain size decreased. A significant red shift in the UV absorbing band edge was observed with the increase in the amount of the Mn and Co contents. [ABSTRACT FROM AUTHOR]

Abstract: Effect of Thorium, Lanthanum and Cerium rare-earth ions on the growth and properties of l-arginine phosphate single crystals has been reported. The incorporation of rare-earth dopants into the l-arginine phosphate crystals is confirmed by Inductively Coupled Plasma-Mass Spectroscopy analysis. The unit cell parameters for pure and rare-earth doped l-arginine phosphate crystals have been estimated by powder X-ray diffraction studies. UV–visible studies revealed the transmittance percentage and cut-off wavelengths of the grown crystals. Powder second harmonic generation measurement has been carried out for pure and doped l-arginine phosphate crystals. The dielectric behavior of the grown crystals was analyzed for different frequencies at room temperature. The mechanical properties have been determined for pure and the doped l-arginine phosphate crystals. [Copyright &y& Elsevier]

Abstract: ZnS nanoparticles have been synthesized on a large scale by hydrothermal route using Hexamethylenetetramine (HMTA) as capping agent in aqueous solution. The average grain size of the nanoparticles calculated from the XRD pattern using Scherrer''s formula is about 2–3nm, which exhibit cubic zinc blende structure. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The UV–vis absorption results revealed that the synthesized HMTA capped ZnS nanoparticles exhibit strong quantum confinement effect as the optical energy band gap increased significantly compared to the uncapped and bulk ZnS. Formation of HMTA capped ZnS nanoparticles was confirmed by FTIR studies. Emission spectra show that the HMTA capping not only increases the PL intensity, but also greatly improves the thermal stability of the ZnS nanoparticles. [Copyright &y& Elsevier]

Abstract: 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 13×4×4mm3 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. [Copyright &y& Elsevier]

Abstract: A hydrothermal method has been optimized for the synthesis of ZnS nanoparticles. The nanoparticles were stabilized using Hexamethylenetetramine (HMTA) as surfactant in aqueous solution. The self-assembling of the surfactant molecules in the water solution forms a unique architecture that can be adopted as the reaction template for the formation of nanomaterials. The average grain size of the nanoparticles calculated from the XRD pattern was of the order of 2nm which exhibits cubic zinc-blende structure. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The spectroscopic results revealed that the synthesized ZnS nanoparticles exhibits strong quantum confinement effect as the optical band gap energy increased significantly compared to the bulk ZnS material. Formation of HMTA capped ZnS nanoparticles were confirmed by FTIR studies. The PL spectra exhibit a strong green emission peak around 502nm attributed to some self-activated defect centers related to Zn-vacancies. [Copyright &y& Elsevier]

Abstract: Efforts have been made in optimizing growth conditions for bulk textured growth of RuSr2GdCu2O8 (Ru-1212) employing top seeded growth technique (TSG). Thermal stability and peritectic temperature (T p) have been determined by TG–DTA analysis. The study facilitates appropriate thermal treatments to yield good quality sample. The structural study of the as grown sample has been carried out by X-ray diffraction technique. Morphological study by polarized optical microscope (PLOM) and scanning electron microscope (SEM) reveals the growth mechanism. Subsequently, the stoichiometry has been confirmed by energy dispersive X-ray analysis (EDAX). The observed characterization results show the influence of superconducting property on growth technique and allow one to correlate between the physical properties and experimental technique. [Copyright &y& Elsevier]

Abstract: Nonlinear optical (NLO) material of diaqua (thiocyanato) manganese mercury-N, N-dimethylacetamide (MMTWD) was synthesized in an aqueous solution, and bulk single crystals were grown by slow-cooling and slow-evaporation methods using dimethyl acetamide (DMA) and water (1:1) as a mixed solvent. Elemental analysis of the synthesized MMTWD was studied by CHN analysis. The crystal structure and morphology of MMTWD single crystal were studied by X-ray diffraction analysis. The presence of functional groups, coordination of dimethyl acetamide (DMA) and the water molecules were confirmed by Fourier transform infrared (FTIR) spectrum, which was further confirmed by the laser Raman studies. The thermal stability and thermal decomposition of MMTWD crystals were investigated by means of thermo-gravimetric analysis and differential thermal analysis. Optical transparency of the grown crystal was studied by UV–vis spectroscopy. The linear refractive index of the MMTWD single crystal was measured using Abbey''s refractometer. The second-harmonic generation (SHG) study was carried out by Kurtz powder method. The dielectric loss and dielectric constant measurement as a function of frequency and temperature were measured on MMTWD single crystal. The formation of rectangular etch pits pattern shows the two-dimensional nucleation mechanism. [Copyright &y& Elsevier]

Abstract: The growth and properties of new semiorganic nonlinear optical crystal, tetra l-lysine alanine mono hydrochloride dihydrate (TLAMHCl) have been studied. TLAMHCl crystals were grown from aqueous solution by slow cooling technique. Solubility of the synthesized material has been determined for various temperatures using water as solvent. Spectral, thermal and optical techniques have been employed to characterize the new materials. Bulk single crystals of size 2.3cm×1.7cm×1.3cm of TLAMHCl have been grown by slow cooling method. The powder X-ray diffraction pattern of the grown TLAMHCl has been indexed. Functional groups present in the sample were identified by FTIR spectral analysis. Thermal stability of TLAMHCl was determined using TGA/DTA curves. Vicker''s microhardness study was carried out at room temperature. The Kurtz powder second harmonic generation test shows that the compound is a potential candidate for optical second harmonic generation. The second harmonic generation (SHG) efficiency of TLAMHCl was found to be 1.2 times that of potassium dihydrogen phosphate (KDP). [Copyright &y& Elsevier]

Abstract: Pure and cobalt doped titanium dioxide thin films have been prepared on glass and Si (100) substrates by sol–gel spin coating method. The structural and optical properties of the films as a function of cobalt concentration (up to 15 wt.%) have been systematically studied by Rutherford backscattering spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, optical spectroscopy and spectroscopic ellipsometry methods. Rutherford backscattering studies show the presence of cobalt dopant in the films is almost equal to the precursor stoichiometry. Grazing incidence X-ray diffraction and Raman spectroscopy studies confirm the amorphous phase of the as-deposited films and crystalline anatase phase for the films annealed at 600 °C. The optical spectroscopy measurements show that the films are fully transparent in the visible region and there is a band gap narrowing upon increasing cobalt dopant concentration. The refractive index, band gap (E g) and thickness of the films were determined from spectroscopic ellipsometry measurements. The refractive index of the films was found to increase from 2.2 to 2.7 with the increase in cobalt concentration with a simultaneous decrease of band gap from 3.1 to 2.8, which is favorable for photocatalytic applications. The packing density of the films was calculated by Clausius–Mossotti relation and is found to increase with cobalt concentration. [Copyright &y& Elsevier]