Effect of Mg on the Structural, Optical and Thermoluminescence Properties of Li3Al3(BO3)4: Shift in Main Glow Peak.

The doping of magnesium on lithium aluminium borate phosphor is reported in this study. A solid-state sintering technique was employed as the borate samples were synthesized. This report focuses on the structural, optical, thermoluminescence, and kinetic analyses of the main glow peak. The structural properties of lithium aluminium borates improved due to the magnesium dopants used. Differences in the crystallite size and particle size were 38.85-67.35 nm and 50-60 nm, respectively, and these results were obtained from the analyzed X-ray diffractogram and scanning electron spectroscopy. The energy band gaps obtained from the direct transition of borate phosphor materials were within the range of 3.00-4.40 eV, and the doped samples gave a higher energy band gap. A decrease in the TGA (%) exhibited a weight loss or water loss for the undoped, 0.1% Mg, and 0.3% Mg-doped lithium aluminium borate materials. The glow curve measured at a heat rate of 1 °C·s-1 after irradiation to 50 Gy revealed four peaks related to the magnesium doped lithium aluminium borate. The main glow peak was observed at 86 °C. Activation energy was extracted from the main glow peak by using kinetic analysis which involves the initial rise, deconvolution, and variable heating rate approach, and it was approximately 0.67 ± 0.03 eV. A shift in the main glow peak curve from 86 to 110 °C was recognized for the magnesium-doped lithium aluminium borate when it was irradiated from 1 to 300 Gy.

Mathematical models for thermionic emission current density of graphene emitter.

In this study, five mathematical models were fitted in the absence of space charge with experimental data to find a more appropriate model and predict the emission current density of the graphene-based thermionic energy converter accurately. Modified Richardson Dushman model (MRDE) shows that TEC's electron emission depends on temperature, Fermi energy, work function, and coefficient of thermal expansion. Lowest Least square value of [Formula: see text] makes MRDE most suitable in modelling the emission current density of the graphene-based TEC over the other four tested models. The developed MRDE can be adopted in predicting the current emission density of two-dimensional materials and also future graphene-based TEC response.

Synthesis and Studies of Electro-Deposited Yttrium Arsenic Selenide Nanofilms for Opto-Electronic Applications.

Nanocomposite films grown by incorporating varying concentrations of Yttrium, a d-block rare-earth ion, into the binary chalcogenide Arsenic selenide host matrix is here presented. Films were grown via the wet-chemical electro-deposition technique and characterized for structural, optical, surface morphology, and photoluminescence (PL) properties. The X-ray Diffraction (XRD) result of the host matrix (pristine film) showed films of monoclinic structure with an average grain size of 36.2 nm. The composite films, on the other hand, had both cubic YAs and tetragonal YSe structures with average size within 36.5-46.8 nm. The fairly homogeneous nano-sized films are shown by the Scanning Electron Microscopy (SEM) micrographs while the two phases of the composite films present in the XRD patterns were confirmed by the Raman shifts due to the cleavage of the As-Se host matrix and formation of new structural units. The refractive index peaked at 2.63 within 350-600 nm. The bandgap energy lies in the range of 3.84-3.95 eV with a slight decrease with increasing Y addition; while the PL spectra depict emission bands across the Vis-NIR spectral regions. Theoretically, the density functional theory (DFT) simulations provided insight into the changes induced in the structure, bonding, and electronic properties. Besides reducing the bandgap of the As2Se3, the yttrium addition has induced a lone pair p-states of Se contributing nearby to Fermi energy level. The optical constants, and structural and electronic features of the films obtained present suitable features of film for IR applications as well as in optoelectronics.

Effects of alkali and transition metal-doped TiO2 hole blocking layers on the perovskite solar cells obtained by a two-step sequential deposition method in air and under vacuum.

Planar perovskite solar cells (PPSCs) have received great attention in recent years due to their intriguing properties, which make them a good choice for photovoltaic applications. In this work, the effect of alkali and transition metal-doped TiO2 (cesium-doped TiO2 (Cs-TiO2) and yttrium-doped TiO2 (Y-TiO2)) compact layers on the optical, structural and the photovoltaic performance of the PPSCs have been investigated. The perovskite layer syntheses were carried out by depositing a lead iodide (PbI2) layer via spin-coating; converting PbI2 into methyl ammonium iodide (CH3NH3PbI3) by chemical vapor deposition (CVD) and spin-coating at 60 min and 60 s conversion times respectively. The as-deposited PPSCs were studied layer-by-layer using an X-ray diffractometer, scanning electron microscope, and UV-vis diffuse reflectance, transmittance and absorbance. The power conversion efficiency for stable processed perovskite solar cells were 3.61% and 12.89% for air and vacuum processed, respectively.

Biosynthesis of iron oxide nanoparticles via a composite of Psidium guavaja-Moringa oleifera and their antibacterial and photocatalytic study.

Human pathogenic diseases are on the rampage in the list of debilitating diseases globally. The endless quest to salvage this menace through various therapies via innocuous agents is essential to overcome these drug-resistant pathogens. This study engaged a benign, facile, biocompatible, cost-effective and eco-friendly approach to synthesized iron oxide nanoparticles (FeO-NPs) via a composite of Psidium guavaja-Moringa oleifera (PMC) leaf extract to address six most debilitating bacterial strain in vitro as an antibacterial agent. Physicochemical analysis of PMC formed nanoparticles (PMC_NPs) was effectuated through Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Spectroscopy, X-ray Diffraction Spectroscopy (XRD), Transmission Electron Microscopy (TEM), and Vibrating Sample Magnetometer (VSM). The PMC_NPs inhibited the growth of six human pathogens with higher activity at lower concentrations. It is noteworthy from our observations that, the bacterial strains show functional susceptibility to the PMC_NPs at lower concentrations compared to the orthodox antibacterial drugs. Photocatalytic degradation was observed with a decrease in the absorbance of Methylene blue dyes with the help of PMC_NPs apropos irradiation time under visible light irradiation. Consequently, PMC_NPs serve as an enhanced substitute for the orthodox antibacterial drugs in therapeutic biomedical field sequel to its pharmacodynamics against the bacterial strains at lower concentrations and also serves as a good component for water purification.

Industrial textile effluent treatment and antibacterial effectiveness of Zea mays L. Dry husk mediated bio-synthesized copper oxide nanoparticles.

Zea mays L. dry husk extract was used to bio synthesize copper oxide nanoparticles. Red coloured cubic Cu2O nanoparticles were obtained for the first time via this simple, eco- friendly, green synthesis route. The Cu2O nanoparticles were thermally oxidized to pure monoclinic CuO nanoparticles at 600 °C. The phases of the copper oxides were confirmed from the x-ray diffraction (XRD) studies. The nanoparticle sizes as obtained from high resolution transmission electron microscope (HRTEM) analysis range from 10 to 26 nm, 36-73 nm and 30-90 nm for the unannealed Cu2O, 300 °C and 600 °C annealed CuO respectively. The values of the bandgap energies obtained from diffuse reflectance of the nanoparticles are 2.0, 1.30 and 1.42 eV respectively for the unannealed, 300 °C, and 600 °C annealed copper oxide nanoparticles. The 600 °C annealed copper oxide nanoparticles showed 91% and 90% degradation ability for methylene blue dye (BM) and textile effluent (TE) respectively under visible light irradiation. While CuO_300 is more effective to inhibit the growth of Escherichia coli 518,133 and Staphylococcus aureus 9144, Cu2O is better for Pseudomonas aeruginosa and Bacillus licheniformis. The results confirm the photo-catalytic and anti-microbial effectiveness of the copper oxide nanoparticles.