Standard JCPDS Data Research Articles

Photoluminescence studies of Sr3P4O13: Eu3+ phosphor prepared by wet chemical method: Structural properties, charge compensation via alkali metal ions and Judd-Ofelt analysis

The Sr3P4O13:Eu3+ phosphors co-doped with alkali metal ions (A+ = Li+, Na+ and K+) were prepared by wet chemical method. The comparison with standard JCPDS data confirmed the formation of a triclinic crystalline phase with P-1(2) space group for the Eu3+ doped Sr3P4O13 phosphor and co-doped with alkali metal ions. The Li+ co-doped Sr3P4O13:Eu3+ phosphor has comparatively sharp and intense XRD patterns. The scanning electron microstructural analysis confirmed the formation of the particles size of 5 -50 μm. The comparative study of photoluminescence properties depicted that the peak positions were similar for all the prepared samples. The photoluminescence analysis of Sr3P4O13:Eu3+ phosphors show the emission in the red-orange region under the excitation of 394 nm (7F0→5L6) wavelength. Further, the charge compensation using alkali metal ions shows the larger photoluminescence intensity observed in the case of the Li+ co-doped Sr3P4O13:Eu3+ phosphors suggesting that the Li+ ion is better charge compensator among the studied alkali metal ions. Further, Judd-Ofelt (J-O) parameters were estimated for the Sr3P4O13:Eu3+ phosphors and co-doped with alkali metal ions in a series of samples. The comparison of Sr3P4O13:Eu3+ phosphors co-doped with alkali metal ions alongwith the J-O estimated parameters have been presented in the article.

Exploiting Rhizobium for Cadmium Sulphide Nanoparticle Synthesis: Heterologous Expression of an Escherichia coli DH10B Enzyme, YbdK [EC: 6.3.2.2] in Sinorhizobium fredii NGR234

Escherichia coli DH10B has 1.1 kb ybdK gene which is responsible for encoding YbdK enzyme that possess a Gamma glutamyl cysteine synthetase activity. ybdK gene was ligated downstream of a constitutive derepressed lac promoter of a low copy number plasmid vector pBBR1MCS-2, giving rise to a recombinant plasmid pPAT. Sinorhizobium fredii NGR234 transformed with pPAT showed an augmented production of glutathione which in turn increased the production of cadmium sulphide nanoparticles to some extent. Also, a heterologous expression of YbdK in Sinorhizobium fredii NGR234 improved the oxidation status of bacterial cells which is confirmed by fluorescence microscopy images and fluorometry. Genetically modified (GM) cells stained by DCFDA showed a significant decrease in fluorescence compared to wild type (WT) cells. Physical and chemical properties of the nanoparticles produced by the pPAT transformed Sinorhizobium fredii NGR234 differed significantly compared to wild type (WT) Sinorhizobium fredii NGR234. Comparative analysis of the nanoparticles by FTIR and SEM analysis revealed the functional groups attached to nanoparticles and average nanoparticle size respectively. Nanoparticles synthesized by genetically modified (GM) bacteria were about 3 times smaller in size compared to those produced by wild type (WT) rhizobium. FTIR analysis revealed an augmented presence of peptide with the nanoparticles produced by GM bacteria compared to those produced by the WT bacteria. XRD data revealed that biosynthesized CdS nanoparticles are face centered crystalline particles which was confirmed by comparing the peaks to standard JCPDS data (JCPDS card no. 10-454).

A cost effective SiO2-CaO-Na2O bio-glass derived from bio-waste resources for biomedical applications.

The present paper describes the in vitro bioactivity, cytocompatibility and degradation performance of SiO2-CaO-Na2O bio-glass synthesized using bio-waste. Egg shells and rice husk ash (RHA) bio-wastes were used as sources of calcium oxide (CaO) and silica (SiO2), respectively. Glass samples were obtained by melt-quenching technique. Bioactivity was studied using in vitro experiments in simulated body fluid (SBF), degradation behaviour was evaluated in Tris-HCl buffer solutions recommended by ISO 10993-14 standards and cytocompatibility was estimated using MTT assay. The formation of hydroxyapatite was characterized by XRD, FTIR and SEM-EDS after soaking the glass samples in SBF solution. XRD confirmed the phase of hydroxyapatite with its standard JCPDS data. FTIR analyses revealed the occurrence of distinctive functional groups related to hydroxyapatite. Surface micrographs showed the agglomerated globular shape morphology of hydroxyapatite, while EDS analysis confirmed the existence of biological elements of apatite such as Ca, P and O. Degradation study results showed that the glass thus prepared has considerable controlled degradation rate. MTT assay revealed the cytocompatibility nature for different dosages (1000-50μg/mL) of the prepared glass with MG-63 cells. These results perfectly established that egg shells and RHA are potentially beneficial resources for the production of bio-glasses.

Thermally static stokes fluorescence based self and Sm3+ activated SrWO4 luminophores for application in LED and visual display unit

Ceramic samples of pure and Sm3+ activated SrWO4 luminophores have been synthesized by solid state reaction technique. The confirmation of the sample formation is obtained by analysing and comparing the XRD data with standard JCPDS data. The material shows the single tetragonal phase with space group I41/a. The surface morphology is analysed by Field Emission Scanning Electron Microscope. The interacting behavior of the prepared material with UV and visible light is studied by recording the data in the diffuse reflectance mode to calculate the optical band gap using UV–Visible Spectrophotometer. The room temperature photoluminescence property of the material is studied by recording the excitation and emission spectra along with the decay kinetics. The PL emission spectra contain the emission peaks of the host due to structural defect of the lattice as well as the emission peaks of Sm3+ ions due to its f-f transitions. To check the high temperature utility of the material, temperature dependent photoluminescence property is studied very cautiously by joining the temperature control setup (Optistate DN2 (Oxford instrumental)) to the sample chamber. The luminescence intensity does not degrade much, as the temperature increases from room temperature to 475 K. The photometric study reveals the color-tunable emission of the material from deep blue to light blue region.

Near-ultraviolet excited Tm3+ and Dy3+ ions co-doped barium lanthanum silica oxide phosphors for white-light applications

Nowadays, trivalent rare-earth ions activated inorganic luminescent materials have been widely investigated owing to their important applications in solid-state lighting field. Tm3+ and Dy3+ ions single- or co-doped Ba3La6(SiO4)6 (BLSO) phosphor materials for white light application were synthesized by a citrate-based sol-gel method. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy and Fourier-transform infrared spectroscopy to analyze the phase purity, surface morphology and existence of functional groups, respectively. The XRD pattern confirmed that the BLSO host lattice exhibited a hexagonal crystal structure with P63/m (176) space group, which is well indexed with standard JCPDS data. From photoluminescence results, the BLSO:Tm3+ phosphors exhibited purplish blue emission at 453 nm (1D2→3F4) and the BLSO:Dy3+ phosphors showed predominant yellow emission at 575 nm (4F9/2 → 6H13/2) compared to their shoulder blue emission at 479 nm (4F9/2 → 6H15/2), indicating that the Dy3+ ions occupied lattice sites with low inversion symmetry. The determined Commission Internationale de I’Eclairage (CIE) (0.3391, 0.3302) values for the Tm3+/Dy3+ co-doped BLSO phosphors were near to the standard sun light CIE values (0.33, 0.33) under near-ultraviolet (364 nm) excitation. The energy transfer process from Dy3+ to Tm3+ ions was discussed and it was proved by their corresponding decay curves. Additionally, thermal study was carried out for the optimized phosphor and it maintained superior thermal PL properties.

Fluorine-doped nanocrystalline ZnO powders prepared via microwave irradiation route as effective materials for photocatalyst

In this report, we have successfully synthesized nanocrystalline pure and F doped ZnO prepared by one-step microwave irradiation method without using any post annealing treatment. The effect of F dopant on structural, morphological and optical properties were systematically investigated by using powder X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Raman spectra, UV–Vis absorption spectra and photoluminescence spectra analysis. XRD results reveals that both pristine and F doped ZnO had a hexagonal wurtzite type structure and the results are in good agreement with standard JCPDS data (card no. 36-1451). FESEM images showed that random platelets morphology with average diameter around 50–35 nm. A considerable red-shift in the absorption edge and decreasing the band gap of pure ZnO (3.32–3.12 eV) was confirmed though UV–Vis spectra. The defect in crystal and oxygen vacancy was analyzed through PL spectra analysis. The photocatalytic activities of the catalyst powders were evaluated by photocatalytic degradation of methyl violet (MV) and rhodamine B (RhB) and the results showed that the doping of F into ZnO nanoparticles could enhance photocatalytic activity compared to the undoped ZnO nanoparticles, this could be due to reduction of band gap and superior textural properties. The improved photocatalytic mechanism by F doping was also discussed in detail.

A comparative study of humidity sensing and photocatalytic applications of pure and nickel (Ni)-doped WO3 thin films

Nanocrystalline of pristine and nickel (Ni)-doped tungsten trioxide (WO3) thin films was deposited by chemical bath deposition method. The concentrations of Ni ions were varied from 0 to 10 wt%. In order to improve the crystallinity of the films were annealed at 600 °C for 2 h in the ambient atmosphere. X-ray diffraction results reveal that the WO3 doped with nickel crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0951). AFM micrographs reveal that average grain size of about 27–39 nm for pure and Ni-doped WO3 thin films. In addition, the band gap of the Ni-doped WO3 nanostructures is facilely tunable by controlling the Ni contents. The humidity sensor setup was fabricated and measured for pure and Ni-doped WO3 thin film sensor with various level of RH (10–90%). The Ni-doped WO3 sensor showed fast response and high sensitivity than pure WO3. The photocatalytic activities of the films were evaluated by degradation of methyl orange, methylene blue and phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of WO3 nanostructures could be remarkably enhanced by doping the Ni impurity.

Structural and electrical properties of La0.9Dy0.1MnO3 prepared by sol–gel technique

Nanosized particles of La0.9Dy0.1MnO3 were prepared by sol–gel technique using citric acid as a chelating agent. The compound was analysed by powder X-ray diffraction technique and found to be single-phased orthorhombic in structure with space group Pnma which was confirmed with standard JCPDS data. The structural and morphological characterisations of synthesised material were carried out using XRD, Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectrometer. The magnetic study at room temperature shows the paramagnetic behaviour of the material. The existence of space charge polarisation and relaxation is due to the presence of oxygen vacancy illustrated from the real and imaginary part of impedance, respectively. The activation energy of synthesised material is calculated using Arrhenius equation from the impedance spectroscopy which corresponds to the existence of oxygen vacancy.

Effect of annealing temperature on structural, optical and humidity sensing properties of indium tin oxide (ITO) thin films

Tin doped indium oxide (ITO) thin films were prepared by sol–gel spin coating method with In (NO3)·3H2O and SnCl4·5H2O as indium and tin sources, respectively. The as deposited samples were annealed at various temperature such as, 300, 400, 500 and 600 °C for 2 h in ambient atmosphere. The grown ITO thin films are polycrystalline in nature with cubic structure of In2O3 with the space group La3 and the results are in good agreement with the standard JCPDS data (card no#06-0416). In addition crystalline size increases with increasing annealing temperature from 25 to 55 nm. Polycrystalline with uniform smooth surface was observed by SEM micrographs. The optical band gap energy was found to be decreased from 3.85 to 3.23 eV as the annealing temperature is increased from 300 to 600 °C. The humidity sensing performance (high sensitivity and fast response time) was significantly improved for 600 °C thin films samples, which is probably due to smaller energy band gap and physisorption between the water molecules and the surface of the thin films. The films were further characterized by PL and EDS analysis. The effect of temperature on humidity sensing mechanism of ITO thin films is also discussed.

A facile and one step synthesis of large surface area SnO2 nanorods and its photocatalytic activity

High quality single crystalline SnO2 nanorods (NRs) were successfully synthesized by using novel microwave-irradiation method by using PEG-400 as surfactant. Powder X-ray diffraction (XRD) results reveals that the SnO2 crystalline with tetragonal rutile type structure (space group P42/mnm) have formed directly during the microwave irradiation process. The results are good in agreement with the standard JCPDS data (file no. 41-1445). Transmission electron microscope (TEM) images showed that NRs of about 460–530 nm in length and 55–75 nm in diameter. UV–visible diffusion reflectance spectroscopic (DRS) studies exposed the band gap energies of SnO2 was found to be 3.27 and 2.58 eV for without and with PEG respectively. The photocatalytic activity study showed that the as-synthesized SnO2 NRs were superior photocatalytic performance for the degradation of methylene blue (MB) and rhodamine B (RhB) dye solutions. The samples were further characterized by photoluminescence and energy dispersive spectra analysis.

A facile and one step synthesis of W doped SnO2 nanopowders with enhanced humidity sensing performance

High sensitivity and fast response humidity sensor based W doped SnO2 nanopowders were prepared by hydrothermal method. The structural, morphological and optical properties of the films nanopowders were analysed by using powder X-ray diffraction (XRD), Transmission electron microscope (TEM), UV–Vis transmission spectra, Fourier transform infra-red spectra and photoluminescence spectra analysis. XRD results suggest that both pure and W doped samples had a tetragonal rutile type structure and the results are in good agreement with the standard JCPDS data (card no# 41-1445). The uniform distribution and well crystalline elongated spherical shaped rod like morphology was observed by TEM micrographs. UV and PL results confirmed the optical property of pristine SnO2 was significantly improved by W doping. Humidity sensor set up was fabricated and tested for relative humidity (RH) variation from 10 to 90%. The 10 wt% doped W sample showed high sensitivity fast response and recovery time as compared to other samples. The humidity sensing results showed that W–SnO2 can be used as active nanostructures for humidity sensors. The humidity sensing mechanism was also discussed in detail.

Effect of Fe doping on structural, optical and photocatalytic activity of WO3 nanostructured thin films

We have successfully synthesized pure and iron (Fe) doped tungsten trioxide (WO3) and nanothin films were deposited by chemical bath deposition method on glass substrates coated with FTO (F-doped tin oxide). The as-deposited films were annealed at 600 °C for 2 h in ambient atmosphere in order to improve crystallinity and structural perfection. The effect of Fe doping on structural, optical, and morphology of thin films was analyzed by X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectra, UV–Vis spectra, Photoluminescence (PL), and Atomic force micrograph (AFM) images. The XRD measurements showed that both the pristine and Fe doped WO3 films crystallize in monoclinic structure and the results are in good agreement with the standard JCPDS data (Card no: 83-0950). The surface of the films are very smooth and the calculated roughness value is around 28–17 nm, which is in good agreement with the average crystallite sizes calculated by Scherrer’s formula. The optical band gap energy of was found to be decreased from 3.12 to 2.92 eV with increase of Fe concentrations (0–10 wt%). The photocatalytic activities of the films were evaluated by degradation of methylene orange (MO and Phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of Fe (10 wt%) doped WO3 film was much higher than that of the pure WO3. The improved photocatalytic mechanism by Fe doping is also discussed.

Effect of W doping on structural, optical and photocatalytic activity of SnO2 nanostructure thin films

In the present work, magnesium (Mg) doped SnO2 nanocrystalline thin films were synthesized by simple chemical bath deposition technique. The as-deposited films were annealed at 600 °C for 5 h in ambient atmosphere in order to improve crystallinity and structural perfection. The influence of Mg doping on structural, optical, and morphology of thin films was studied by X-ray diffraction (XRD), Raman spectra, UV–Vis Spectra, photoluminescence, and atomic force micrograph images. The XRD measurements showed that films had a tetragonal rutile type structure with P42/mnm symmetry and the results were good in agreement with the standard JCPDS data (card no: 41-1445). The surface roughness has been found to decrease with the increase of the dopant concentration as investigated by atomic force microscopy. The optical band gap energy of pure SnO2 has been found to be in the range of 3.63 eV and it is shifted to 3.42 eV for 10 wt% Mg doping. In the Raman spectrum, two active mode (A2u and Eu) were observed for Mg–SnO2 thin films. The photocatalytic activities of the films were evaluated by degradation of methylene blue rhodamine B in an aqueous solution under ultraviolet light irradiation. The photocatalytic activity of Mg (10 wt%) doped SnO2 film was much higher than that of the pure SnO2. The samples were further characterized by photoluminescence spectra analysis.

Influence of Zn doping on structural, optical and photocatalytic activity of WO3 nanoparticles by a novel microwave irradiation technique

In the present work we have successfully synthesized pure and zinc (Zn) doped WO3 nanoparticles by microwave irradiation method for the first time. Powder X-ray diffraction results reveal that the WO3 doped with Zn concentration from 0 to 10 wt% crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0950). Field emission scanning electron microscopy studies illustrate that both the pristine and Zn doped WO3 form in spherical shaped morphology with an average diameter of 48–36 nm, which is in good agreement with the average crystallite sizes calculated by Scherrer’s formula. A considerable red shift in the absorbing band edge and decrease the band gap energy from 2.93 to 2.71 eV for Zn doped samples was observed by using UV–Vis spectra analysis. The defects in crystal and oxygen deficiencies were analyzed by photoluminescence spectra analysis. The photocatalytic activities of the pure and Zn doped WO3 samples were evaluated by the degradation of methylene blue rhodamine B in an aqueous solution under visible light irradiation. The photocatalytic activity and reusability of Zn (10 wt%) doped WO3 was much higher than that of the pure WO3. The improvement mechanism by Zn doping was also discussed.

Influence of Cu doping on structural, optical and photocatalytic activity of SnO2 nanostructure thin films

In the present work, magnesium (Mg) doped SnO2 nanocrystalline thin films were synthesized by simple chemical bath deposition technique. The as-deposited films were annealed at 600 °C for 5 h in ambient atmosphere in order to improve crystallinity and structural perfection. The influence of Mg doping on structural, optical, and morphology of thin films was studied by X-ray diffraction (XRD), Raman spectra, UV–Vis Spectra, photoluminescence, and atomic force micrograph images. The XRD measurements showed that films had a tetragonal rutile type structure with P42/mnm symmetry and the results were good in agreement with the standard JCPDS data (card no: 41-1445). The surface roughness has been found to decrease with the increase of the dopant concentration as investigated by atomic force microscopy. The optical band gap energy of pure SnO2 has been found to be in the range of 3.63 eV and it is shifted to 3.42 eV for 10 wt% Mg doping. In the Raman spectrum, two active mode (A2u and Eu) were observed for Mg–SnO2 thin films. The photocatalytic activities of the films were evaluated by degradation of methylene blue rhodamine B in an aqueous solution under ultraviolet light irradiation. The photocatalytic activity of Mg (10 wt%) doped SnO2 film was much higher than that of the pure SnO2. The samples were further characterized by photoluminescence spectra analysis.

Synthesis of monodisperse WO 3·2H 2O nanospheres by microwave hydrothermal process with l (+) tartaric acid as a protective agent

Monodisperse crystalline WO 3·2H 2O (H 2WO 4·H 2O) nanospheres have been prepared by l (+) tartaric acid-assisted microwave hydrothermal (MH) process for the first time. The X-ray powder diffraction (XRD) pattern indicated that the product was in good agreement with the standard JCPDS data for WO 3·2H 2O. The particle sizes and shapes have been measured by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. The effects of the mass ratios of l (+) tartaric acid to Na 2WO 4·2H 2O on the morphology of WO 3·2H 2O have been investigated. Finally, The formation mechanism for l (+) tartaric acid-assisted MH synthesis of the WO 3·2H 2O nanospheres was also discussed in detail.

Hydrothermal synthesis of monodisperse WO 3·H 2O square platelet particles

Monodisperse particles of tungsten(VI) oxide monohydrate were prepared in a hydrothermal system at 40 °C, where 20 ml of HCl solution (1.50 mol/l) was added to the same volume of Na 2WO 4 aqueous solution (0.50 mol/l) with magnetic stirring, followed by standing in an air oven for 168 h. The shape of the particles was square platelet and the mean size was 0.72 μm with 10% of the coefficient of variation. The XRD pattern was in good agreement with the standard JCPDS data for WO 3·H 2O. The effects of counter cation and anion of the starting materials in addition to the preparation temperature and acid concentration were also examined.