Space Group P63mc Research Articles

Methylene blue dye degradation potential of zinc oxide nanoparticles bioreduced using Solanum trilobatum leaf extract

Ecofriendly synthesis of zinc oxide nanoparticles (ZnO NPs) was carried out using Solanum trilobatum (S. trilobatum) leaf extract as bioreducing agent. SEM images disclosed spherical ZnO NPs formation having a mean diameter of ∼25 nm. EDAX spectrum demonstrated presence of Zn and O elements and absence of peaks corresponding to impurity elements that revealed purity of ZnO NPs. X-ray diffraction pattern displayed diffraction peaks associated with hexagonal wurtzite structured ZnO. Rietveld refinement analysis of XRD data indicated that ZnO NPs have hexagonal single phase (P63mc space group). Profile parameters (Rp, Rwp, and χ2) with minimum values designated harmony between calculated and observed diffraction patterns. FTIR spectrum of ZnO NPs signified high intense band at 540.94 cm−1 associated with characteristic stretching of Zn–O bond. Photocatalytic performance of ZnO NPs showed noticeable methylene blue dye decomposition with an efficiency of 94.07 % under sunlight illumination. Total organic carbon analysis disclosed considerable removal of organic carbon content from the methylene blue dye. Conclusively, S. trilobatum leaf extract can be employed as bioreductant agent to synthesis semiconductor nanomaterials for environmental remediation applications.

SYNERGETIC EFFECT OF Sn3+ ON STRUCTURAL, OPTICAL AND DIELECTRIC PROPERTIES OF ZnO NANOSTRUCTURES

This work shows the impact of Sn3+ ion doping on structural, optical and dielectric properties of ZnO synthesized via co-precipitation technique. The synthesized samples were examined using XRD (X-ray Diffractometer), FeSEM (Field Emission Scanning Electron Microscope), FTIR (Fourier Transform Infrared Spectroscopy), PL (Photoluminescence) and Impedance Spectroscopy. The XRD patterns confirmed the hexagonal structure with P63mc space group and the crystalline sizes, strain and volume of cell are 37.4 nm, 2.5968Å and 59.85Å3 . The morphological micrographs were recorded via S EM. The photoluminescence spectra were measured using a photoluminescence spectrometer with a 325 nm excitation wavelength. FTIR (Fourier Transform Infrared Spectrometer) spectrometer was used to measure IR spectra in the range 500 − 3600 cm-1 . Complex impedance spectroscopy of the Sn3+ /ZnO − 400 samples was performed at 310 K using a galvenostat in the frequency range of 5MHz to 50 Hz at applied voltage of 50mV. The grain edge resistance of the Sn3+ /ZnO − 400 sample is 14.57MΩ (at 310 K).

Study of dipole polarization in Zn doped barium hexaferrite

The BaFe12O19 is a ferrimagnetic ordering material, but well known as ferromagnetic material. Also, it exhibits high dielectric constant which motivate to explore the multiferroic properties in this material. Hence, researchers are interested to explore its electrical properties in the recent era. Hence, in the present report, the sol–gel prepared Zn doped barium hexaferrite has been considered to explore its electrical properties. The spontaneous polarization is observed for Zn doped barium hexaferrite. The presence of dipole polarization in barium hexaferrite could be due to presence of non-centrosymmetric P63mc (no. 186) space group. The increase in dipole polarization is observed with the increase in Zn concentration in BaFe12O19. The enhanced ferroelectric parameters like Pm, Pr and Ec are found to be 0.275 µC/cm2, 0.254 µC/cm2 and 29.0 kV/cm for BaFe11.4Zn0.6O19 sample, respectively.

Zinc oxide nanoparticles for detection of latent fingermarks on nonporous surfaces

In the present study, zinc oxide (ZnO) nanoparticles were synthesized using hydrothermal method. The prepared nanoparticles were characterized by powder X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, diffused reflectance spectroscopy and Fourier transform infrared spectroscopy. The PXRD confirms the hexagonal phase of the ZnO nanoparticles having space group P63mc and lattice parameters a = b = 3.2498 Å, c = 5.2066 Å. The obtained ZnO nanoparticles are spherical with an average size of ∼12.8 nm as confirmed by TEM. XPS analysis confirms Zn to be in the +2 oxidation state. These nanoparticles were used to develop fresh and aged (24 h old) latent fingermarks on dry and moist non-porous surfaces using powder dusting method. These nanoparticles develop sharp and clear fingerprints and second level details of the fingerprints without any background noise can be viewed on glass and aluminum surfaces. The developed nanoparticles are non-hazardous and cost-effective in nature. The proposed powder formulation is a simple to prepare and can be efficiently used to develop latent fingermarks on wide range of dry and wet, smooth, non-porous surfaces recovered from scene of crime.

Missing Member in the MII MIII Si4 N7 Compound Class: Carbothermal Reduction and Nitridation Synthesis Reveal Substitution of Nitrogen by Carbon and Oxygen in CaLu[Si4 N7-2x Cx Ox ]:Eu2+ /Ce3+ (x≈0.3).

The nitridosilicate CaLu[Si4N7–2x C x O x ] (x≈0.3) was synthesized by carbothermal reduction and nitridation starting from CaH2, Lu2O3, graphite and amorphous Si3N4 at 1550 °C in a radiofrequency furnace. CaLu[Si4N7–2x C x O x ] (x≈0.3) crystallizes isotypically to many previously known M II M IIISi4N7 compounds in the space group P63 mc, as was confirmed by Rietveld refinement based on powder X‐ray diffraction data. Incorporation of carbon into the crystal structure as a result of the carbothermal synthesis route was confirmed by 13C and 29Si MAS NMR spectroscopy. For the first time in the M II M IIISi4N7 compound class, complementary EDX measurements suggest that simultaneous incorporation of oxygen compensates for the negative charge excess induced by carbon, resulting in an adjusted sum formula, CaLu[Si4N7–2x C x O x ] (x≈0.3). When excited with UV‐to‐blue light, CaLu[Si4N7–2x C x O x ] (x≈0.3) shows an emission maximum in the blue spectral region (λ em=484 nm; fwhm=4531 cm−1) upon doping with Ce3+, whereas Eu2+‐doped CaLu[Si4N7–2x C x O x ] (x≈0.3) exhibits a yellow‐green emission (λ em=546 nm; fwhm=3999 cm−1).

Sequential physical vapor deposited methylammonium lead tri-iodide perovskites on FTO and ITO modified zinc oxide nanorods for perovskite solar cells

A comparative study was conducted between methylammonium lead tri-iodide (MAPbI3)/zinc oxide (ZnO) nanorods (NRs) on fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) substrates for the first time. X-ray diffraction micrographs confirmed pure tetragonal MAPbI3 phase with I4/mcm space group and highly textured wurtzite hexagonal ZnO structure, having P63mc space group. Scanning electron micrographs revealed compact MAPbI3 grains on vertically aligned NRs. The average diameter of the NRs was 226 nm on ITO and 233 nm on FTO. Similarly, the average grain sizes of MAPbI3 were 280 nm and 210 nm on FTO/ZnO and ITO/ZnO, respectively. The bandgaps were respectively 3.05 and 3.18 eV for ITO/ZnO and FTO/ZnO, whereas that of FTO/ZnO/MAPbI3 and FTO/ZnO/MAPbI3 were 1.580 and 1.584 eV, accordingly. Our findings indicate that FTO/ZnO/MAPbI3/Au solar cells have a better performance than ITO/ZnO/MAPbI3/Au devices, and in-chamber annealing did not decompose MAPbI3 sequential vapor-deposited on ZnO nanorods.

Defects assisted photosensing and dye degradation of Ni/Ga co-doped ZnO: A theory added experimental investigation

Ni or Ga doping is well studied in literature. However, a Ga/Ni co-doped ZnO brings in complex competing mechanisms of electron mobility and electron localization. A sol-gel prepared solid solution of Ga/Ni co-doped ZnO with hexagonal wurtzite structure (P63mc space group) is studied in detail to correlate the electronic properties to the structure of the materials. Lattice strain studies correlated to these changes in the electronic properties. The drastic reduction in native defects was detailed using the photoluminescence study of Ni/Ga co-doped ZnO. Lattice and phonon studies were used to explain the lattice strain in the ZnO lattice. The % Sensitivity of UV (290 nm), blue (450 nm), green (540 nm) and red (640 nm) wavelengths were tested and correlated with the defects. Additionally, the photo-catalytic dye degradation of toxic methylene blue was investigated and explained with changes in carrier concentration and mobility. The reason behind the conductive parameters was examined theoretically and a possible reason was found in terms of changes in electron localization due to increasing Ni/Ga concentration.

Excellent UV-Light Triggered Photocatalytic Performance of ZnO.SiO2 Nanocomposite for Water Pollutant Compound Methyl Orange Dye.

The photocatalytic activity of eco-friendly zinc oxide doped silica nanocomposites, synthesized via a co-precipitation method followed by heat-treatment at 300, 600, and 900 °C is investigated. The samples have been characterized by employing X-ray diffraction method, and further analyzed using the Rietveld Refinement method. The samples show a space group P63mc with hexagonal structure. The prepared composites are tested for their photocatalytic activities for the degradation of methyl orange-based water pollutants under ultra-violet (UV) irradiation using a 125 W mercury lamp. A systematic analysis of parameters such as the irradiation time, pH value, annealing temperatures, and the concentration of sodium hydroxide impacting the degradation of the methyl orange (MO) is carried out using UV-visible spectroscopy. The ZnO.SiO2 nanocomposite annealed at 300 °C at a pH value of seven shows a maximum photo-degradation ability (~98.1%) towards methyl orange, while the photo-degradation ability of ZnO.SiO2 nanocomposites decreases with annealing temperature (i.e., for 600 and 900 °C) due to the aspect ratio. Moreover, it is seen that with increment in the concentration of the NaOH (i.e., from 1 to 3 g), the photo-degradation of the dye component is enhanced from 20.9 to 53.8%, whereas a reverse trend of degradation ability is observed for higher concentrations.

Synthesis, structure, and nonlinear optical property of Bi0.33Sb0.67SI

The phase transition of SbSI from non-centrosymmetry to centrosymmetry occurs at 292K, which is too low for its practical applications such as ferroelectricity and nonlinear optics. Here, the substitution of Sb by Bi atoms is proposed to improve its phase transition temperature. A new chalcohalide, Bi0.33Sb0.67SI, has been successfully synthesized by self-flux method. It crystallizes in the non-centrosymmetric space group Pmc21 (No. 26) with a ​= ​4.1190 (9) Å, b ​= ​10.225 (2) Å, c ​= ​8.5318 (18) Å. Different from the crystal structure of SbSI, Bi0.33Sb0.67SI is composed of two kinds of edge-sharing distorted square pyramid [MS3I2]5- (M ​= ​Bi or Sb), which form [∞1M2S4I2]4- chains along a axis. The compound exhibits a moderate powder second harmonic generation signal at 2.09 ​μm, which was consistent with its non-centrosymmetric structure.

The First High-Pressure Chromium Oxonitridoborate CrB4 O6 N-an Unexpected Link to Nitridosilicate Chemistry.

CrB4O6N crystallizes in the non‐centrosymmetric space group P63 mc (no. 186) with the lattice parameters a=5.1036(1), c=8.3519(3) Å, and a volume of 188.40(1) Å3. It was synthesized in a high‐pressure/high‐temperature experiment at 7 GPa and 1673 K and represents the first high‐pressure oxonitridoborate. It is built up of starlike‐shaped entities of four BO3N tetrahedra, connected via one common nitrogen atom that resembles the fourfold‐coordinated nitrogen atoms in the homeotypic nitridosilicates MYbSi4N7 (M=Sr, Ba). Building up a network with channels that contain the Cr3+ ions, CrB4O6N contains for the first time a tetrahedral building unit in contrast to trigonal planar B(O/N)3 entities in all other known oxonitridoborates. The structural relations as well as the results of spectroscopic measurements and calculations on the chromium oxonitridoborate are discussed.

Development and design of aluminium nitride disc for high power S-band dielectric window

This study deals with the development of aluminum nitride (AlN) disc for an S-band pillbox-type dielectric window that can handle a peak and average power of 6 M W. and 6 kW, respectively, with a negligible reflection and transmission loss. Pure and Er2O3 doped AlN ceramics with diameters and thicknesses of 10 mm and 5 mm are prepared by solid-state reaction method and sintered by adopting the sintering bed (the combination of AlN/C) at 1700 °C. Interestingly, it prevented the formation of Al2O3 completely. The X-ray diffraction patterns of both pure and Er2O3 doped samples displayed wurtzite crystal structure with the P63mc space group. Compared to the pure samples, the AlN ceramics doped with Er2O3 exhibited microwave dielectric properties (εr = 7.81 and tanδ = 5 × 10−4). The dielectric window is designed in CST by using the experimentally derived dielectric properties. The theoretical value of insertion loss and the return loss of the window is better than 61.25 dB and 0.009 dB, respectively, at a rate of 3.7 GHz.

ZnO nanoparticles prepared via a green synthesis approach: Physical properties, photocatalytic and antibacterial activity

The aqueous extract of Phoenix roebelenii palm leaves has been utilized for the first time as an effective chelating/stabilizing agent used to synthesize zinc oxide nanoparticles (ZnO NPs) via a green chemistry approach. The physical properties of the nanoparticles were examined using X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), simultaneous thermogravimetric analysis (TGA) and differential thermal analysis (DTA), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. Our XRD investigations revealed that the ZnO NPs have a single phase wurtzite structure with P63mc space group. The crystallite size and lattice strain were calculated using X-ray peak broadening analysis utilizing the Williamson-Hall (W-H) method and were found to be 15.6 nm and 2.1 × 10−3 respectively. The shape of the ZnO NPs was almost spherical, as revealed by TEM analysis. The DRS spectrum showed a direct band gap energy of 3.24 eV. DTA/TGA indicated that the required calcination temperature was 500°C in order to form stable ZnO NPs. PL spectroscopy revealed the presence of weak UV emission related to the free exciton and wide visible-light emission due to oxygen vacancies and other structural defects. The reaction between P. roebelenii palm leaves extract and the zinc precursor was monitored using FTIR spectroscopy at different reaction times. The potential mechanism for the formation of the ZnO NPs using P. roebelenii leaves extract as a natural chelating and stabilizing agent has been discussed. The bioinspired ZnO NPs achieved an outstanding degradation activity of 98% toward methylene blue (MB) dye after 105 min of UV illumination. In addition, the ZnO NPs exhibit a significant bactericidal effect towards gram-positive (Staphylococcus aureus and Streptococcus pneumoniae) and gram-negative (Escherichia coli and Salmonella typhi) pathogenic bacteria.

Overlooked Binary Compounds Uncovered in the Reinspection of the La-Au System: Synthesis, Crystal Structures, and Electronic Properties of La7Au3, La3Au2, and La3Au4.

Although compound formation between two elements is well studied, thorough investigations make it possible to uncover new binary compounds. A re-examination of the La–Au system revealed three new phases, which were characterized with respect to their structural and electronic properties as well as thermal stability: La7Au3 (Th7Fe3 type, space group P63mc, Pearson code hP20) appears to be metastable. It can be obtained by slow crystallization from a stoichiometric melt. La3Au2 (U3Si2 type, space group P4/mbm, Pearson code tP10) is stable up to 1013 K, where it decomposes peritectically. La3Au4 (Pu3Pd4 type, space group R3̅, Pearson code hR14) is thermally stable up to at least 1273 K. In addition, the crystal structures of La2Au (anti-PbCl2 type, space group Pnma, Pearson code oP12) and α-LaAu (FeB type, space group Pnma, Pearson code oP8) could be determined by single-crystal X-ray diffraction. The electronic structures and chemical bonding have been evaluated from first principles calculations. They show that all compounds can be viewed as electron-rich, polar intermetallics.

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Synthesis, crystal structure and physical properties of a novel quaternary selenide Cu6GeWSe8

Here we report a novel quaternary selenide Cu6GeWSe8 synthesized directly from the constituent elements, which forms within the temperature range from 460 to 620 ​°C. It crystallizes in the space group P63mc with two formula units in the cell of dimensions a ​= ​7.8651 (5) Å, c ​= ​12.9275 (6) Å. In the unit cell composed of MSe4 (M ​= ​Cu, Ge and W) tetrahedrons, Cu atoms occupy two sets of 6c Wyckoff positions, Ge and W atoms respectively occupy 2a and 2b positions, while Se atoms are located at four inequivalent sites, respectively 2b (Se1), 6c (Se2), 6c (Se3) and 2a (Se4). The electrical resistivity and Vis-Nir absorption spectrum indicate that the compound exhibits a semiconducting behavior with an optical band gap of 1.586 ​eV Cu6GeWSe8 shows diamagnetism at room temperature and the emergence of a Curie-Weiss-like tail at low temperature. The band structure calculation demonstrates that the title compound has a direct band gap, and Cu and Se atoms dominantly contribute to the energy bands and density of states. Cu is mostly in 3d10 state (+1 valence) and Se in 4p6 state (−2 valence). On the basis of the experimental and calculation results, it is concluded that Cu6GeWSe8 is a diamagnetic direct-gap semiconductor.

Effect of synthesis methods on dielectric performance of ZnO nanoparticles

ABSTRACT Zinc oxide (ZnO) nanoparticles are widely studied for the application of dye-sensitised solar cells (DSSCs). The control of nanoscale morphology and microstructural properties of ZnO is critical for DSSCs performance. The current study provides an insight about the effect of synthesis methods (i.e. co-precipitation and sol–gel) on structural, optical and electrical properties of ZnO nanoparticles. The formation of hexagonal wurtzite phase with space group P63mc was confirmed by Rietveld fitted X-ray diffraction and Raman spectroscopy. The variation in morphology due to different synthesis methods was confirmed by Scanning electron microscopy. Functional groups were identified by Fourier transform infrared spectroscopy. The presence of defects led to the narrowing of band gap of ZnO nanoparticles, and was confirmed by diffuse reflectance spectroscopy. The frequency-dependent dielectric behaviour was explained by means of Maxwell–Wagner–Sillars model. The current study paves the way of potential application of ZnO nanoparticles in DSSCs.

Impact of terbium inclusion on the photodetection performance of ZnO thin films

Terbium (Tb)-doped ZnO thin films were fabricated using the successive ionic layer adsorption and reaction route. Their structural, morphological, optical, and ultraviolet photosensing properties were studied and compared with those of pure ZnO thin films. The x-ray diffraction results illustrate that the pure and Tb-doped ZnO films reveal hexagonal structures with the P63mc space group. The 1% Tb-doped ZnO film shows an increase in the absorption and a decrease in bandgap value from 3.24 eV to 3.15 eV compared to pure ZnO. The photoluminescence results reveal the existence of emission centers at 388, 414, 441, and 477 nm in the fabricated thin films. By increasing the rare earth (Tb) element, the near band edge emission was decreased and correspondingly increased the blue emission due to its 4f orbital energy transition. The photosensing parameters, such as responsivity, external quantum efficiency, and specific detectivity values of the 1% Tb-doped ZnO detector, are 2.21 × 10−1 A W−1, 75%, and 1.84 × 1010 Jones, respectively, which are higher compared to the other fabricated devices due to their better optoelectronic properties. For the 5% Tb-doped ZnO detector, the I–V characteristic curve shows a non-linear behavior, which indicates that a small Schottky barrier is formed in the detector due to widening of the potential barrier and depletion region by Tb. We also investigated the possible energy band diagram of both linear and non-linear (Schottky barrier) behaviors for Tb-doped ZnO detectors.

Improved ammonia vapor sensing properties of Al-doped ZnO nanoparticles prepared by sol-gel process

Aluminium-doped ZnO nanoparticles were synthesized using the simple and cost-effective sol-gel route. Their structural, morphological, optical, and ammonia vapor sensing properties were compared with the pristine ZnO sample. The x-ray diffraction results showed that the pristine and Al-doped ZnO samples exhibit a hexagonal structure with the P63mc space group. A detailed structural investigation was carried through the Rietveld refinement technique. The decrease in crystallite size and the increasing nature of the sample’s microstrain were observed through the Williamson-Hall (W-H) analysis. 1-D, 2-D, and 3-D electron density distribution in a single unit cell of ZnO nanoparticles were studied with the maximum entropy method and it is confirmed that the ionic nature of the Zn-O bond increases by Al doping. The surface morphology of the samples was altered significantly after the addition of aluminum with ZnO. Aluminium doping causes a notable bandgap broadening in the ZnO nanostructures. A momentous enhancement of ammonia detection sensitivity of 129% at 25 ppm was observed for the ZnO:Al(3%) sample and its response time is greater than the other tested samples. Further, ZnO:Al(3%) sample exhibits the best response and recovery time of 28 and 8 s, respectively. It has also shown a stable ammonia vapor sensing ability for five consecutive cycles.

Effect on the dielectric properties due to In–N co-doping in ZnO particles

Zinc oxide (ZnO) particles are widely used for various applications, and their tuned structural, optical and dielectric properties can offer significant enhancement in the performance of photovoltaic devices. In the present work, undoped and indium (In)–nitrogen (N) co-doped ZnO particles were synthesized via co-precipitation technique. Moreover, the correlation among their structural, optical and dielectric properties was investigated in detail. X-ray diffraction (XRD) along with Rietveld refinement and Raman analysis confirmed the pure hexagonal wurtzite structure with P63mc space group in all the samples. The surface morphology and formation of metal oxide functional groups were identified by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. Ultraviolet (UV)–visible spectroscopy showed the irregular variations in the band gap with increasing doping concentration that can be explained in terms of lattice strain and defect state formation. The dielectric behavior of all samples was examined as a function of frequency and explained by Maxwell–Wagner model. The observed structural, optical and dielectric behavior of In–N co-doped ZnO particles may open the way for their potential applicability in new emerging photovoltaics such as dye-sensitized solar cells in the near future.

Structural and optical investigation of Co-doped ZnO nanoparticles for nanooptoelectronic devices

Cobalt-doped ZnO nanoparticles (NPs), with concentration of Co2+ varying between 1 and 5%, have been synthesized by a sol–gel procedure. The structural, morphological and optical properties of these nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultraviolet–visible (UV–Vis) measurements. The X-ray diffraction shows that these semiconductors crystallize in a wurtzite single crystalline phase with P63mc space group. In this structure, the cobalt ion Co2+ substitutes for a Zinc ion Zn2+ in a ZnO semiconductor and occupies a tetrahedral Td site symmetry surrounded by four oxygen atoms with a slight distortion. The TEM images characterize the morphology and crystalline structure of these semiconductors. From the UV spectra, a direct bandgap semiconductor was assumed for ZnO:Co2+ NPs. The bandgap energy of the ZnO lattice gradually decreases following the addition of Co2+ ions. The red absorption spectra are ascribed to the electronic transitions of Co2+ ion in ZnO. To determine the electronic structure of the transition ion Co2+, the crystal field theory is applied for the visible spectrum associated with the d–d transitions of this ion located at a Td site symmetry in ZnO NPs. The experimental and theoretical results of energy levels are in agreement. The results were compared to that published for the Co2+ ion in NP ZnO.