Standard JCPDS Research Articles

Structural, morphological and photoluminescence studies of Ca7Mg2P6O24:RE3+(RE3+= Tb3+, Dy3+) nanophosphor for solid state illumination

The Ca7Mg2P6O24:RE3+ (RE3+= Tb3+, Dy3+) nanophosphor material was synthesized by traditional wet chemical method. The XRD are used to determine phase and crystallinity of the synthesized sample; further FTIR, SEM, TEM, and PL properties were studied. The XRD pattern of prepared sample match well with standard JCPDS card no 00–020–0348, and it exhibits the rhombohedral structure along with space group R3c (161). The phosphate (PO4)3-group absorption band was observed at 990–1100 cm-1 in FTIR. Surface morphology (TEM analysis) reveals particle sizes in the range of 55–110 nm. The luminescence emission spectra of Ca7Mg2P6O24 phosphor activated by Tb3+ were studied at three different excitations: 352 nm, 370 nm, and 379 nm. The spectra show two emission peaks at 470 nm (blue) and 545 nm (green). These are due to the 5D4 → 7F6 and 5D4 → 7F5 transitions of Tb3+ ions. The highest intensity peak is located at 545 nm. The Ca7Mg2P6O24:Tb3+ phosphor's CIE chromaticity coordinates are (0.040, 0.316) at 491 nm and (0.265, 0.724) at 543 nm. These are in the blue and green areas on the edges of the CIE diagram, respectively. The photoluminescence emission spectra of Dy3+-doped Ca7Mg2P6O24 phosphor show two significant emission peaks located at 482 nm and 574 nm. These are caused by the 4F9/2 → 5H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, which produce blue and yellow light, respectively, with an excitation wavelength of 350 nm. The sharp peak position at 482 nm produces the strongest emission. The effect of concentration quenching in between the Dy3+-Dy3+ions and Tb3+-Tb3+ ions is due to dipole-dipole interaction. The CIE color coordinate is found to be (0.082, 0.156) at 482 nm and (0.471, 0.527) at 574 nm which lies in blue and yellow border of CIE diagram. The lifespan of Tb3+, Dy3+activated Ca7Mg2P6O24 nanophosphor of highest concentration is found to be 1.917 ms and 0.9985 ms respectively. On investigation, the synthesized Tb3+, Dy3+activated Ca7Mg2P6O24 nanophosphor can be potential for solid lightning devices & other display application.

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.

Structural and Optical Properties of Activated Carbon Derived from Eggshell

This research was done to prepare the eggshell as activated carbon (AC) using the simple chemical activation process. Phosphoric acid (H3PO4) at different molarities of 0.50, 0.75 and 1.00 M is used as an activation agent. All samples were analysed and characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM images show irregular shapes of carbon. XRD patterns of AC were observed at 29.7°, 36.2°, 40.5°, 43.5°, 47.7° and 48.7° which corresponds to Braggs reflection planes of (201), (105), (107), (207), (206) and (304) respectively. The obtained diffraction peaks show the hexagonal crystal structure of carbon and are well matched with standard JCPDS: 721-616. SEM images show that the structure of AC are fake-like structures and exhibit partial geometrical shape when synthesized at 0.50 M. A broad and strong peak is observed at 1400 centimeter and a sharp peak appears at 872 centimeter due to stretching and bending vibration of the carbonate group present in the samples. The band observed at 1071 centimeter corresponds to the vibration of the phosphate group.

Photoluminescence and energy transfer studies in the Sm3+ and Eu3+ co-doped Sr2ZnSi2O7 red-emitting phosphors

In this study, we utilized a high-temperature solid-state reaction method to synthesize the red-emitting phosphors, namely Sr2ZnSi2O7:Sm3+ and Sr2ZnSi2O7:Sm3+/Eu3+. Characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX) revealed that the crystal structure of the as synthesized Sr2ZnSi2O7 samples aligned with the standard JCPDS no. 00-039-0235, featuring small irregularly shaped particles having a tetragonal structure with space group P-421m and space group number 113. The band gap values were determined using diffuse reflectance spectral (DRS) data. Photoluminescence (PL) emission spectra indicated efficient excitation of Sr2ZnSi2O7:Sm3+ and Sr2ZnSi2O7:Sm3+/Eu3+ phosphors under near-ultraviolet light (λex = 404 nm). The PL intensity of Eu3+ ions increased with increasing the concentration of Eu3+ ions, leading to a decrease in the PL intensity of Sm3+ ions. The energy transfer mechanism from Sm3+ to Eu3+ ions is mainly driven by dipole-dipole (D-D) interaction, as predicted using Dexter Reisfeld's approximation. As the concentration of Eu3+ ions increased, there was a reduction in the photoluminescence (PL) decay lifetimes. This decline affirmed the presence of the energy transfer (ET) mechanism from Sm3+ to Eu3+ ions, reaching a maximum transfer efficiency of around 23.11 % in the Sr2ZnSi2O7:Smx/Euy (x = 1.5, y = 5 mol%) phosphor. Computed CIE parameters under UV excitation showed a gradual shift towards the deep red region with increase in Eu3+ concentration. For Sr2ZnSi2O7: Smx/Euy (x = 1.5, y = 5 mol%) phosphor, the CIE color coordinates and color purity were (0.60120, 0.39485) and 95.62 %, respectively. These findings highlight the potential of the synthesized phosphors as solid-state emitters for warm white LED applications, featuring a low color-correlated temperature (CCT) value of 1724 K when stimulated with UV chips.

Structural, Morphological and Optical and Electrical Properties of Ba0.4Cu0.6-xLaxTiO3 (x = 0.2, 0.4, 0.6) Nanoparticles

the structural, morphological, optical and electrical properties of Ba0.4Cu0.6-xLaxTiO3 (x = 0.2, 0.4, 0.6) nanoparticles are discussed. It begins with the preparation followed by characterization of the materials. The sample material is synthesized by hydrothermal technique and then the structure of the present sample is confirmed by diffraction pattern and compared with the respective standard JCPDS pattern. In addition, the structural parameters such as the lattice constant (a), average crystallite size (Dp), theoretical density (ρx), porosity (P), dislocation density (ρd) and strain (ε) are evaluated. In this study, morphology is analyzed using the SEM and TEM measurements. The optical properties such as A, B-site wave numbers, force constants and optical band gap energies (Eop) are studied by FTIR and UV-Visible spectrometers respectively. Electric and dielectric properties have been studied over a frequency range of 100 Hz – 1 MHz and in the temperature range from 40oC to 100oC.

Synthesis, characterization and properties of Cr-doped ZnO nanoparticles via a facile solvothermal route

Cr-doped ZnO ([Formula: see text]–0.08) nanoparticles are synthesized using the microwave solvothermal irradiation technique. The final product is calcinated at 450∘C and the nanostructure of the material is investigated using various techniques. In structural studies, XRD analysis shows that the hexagonal wurtzite structure of ZnO is present in the standard JCPDS card. FESEM spectrum reveals the hexagonal shape of the synthesized samples and EDS provides information on the qualitative composition of the nanoparticles. Optical absorbance images show exciton peaks in the UV region, which can be attributed to Cr incorporation into the ZnO lattice, and the optical energy bandgap values are calculated using the tauc plot method. Photoluminescence (PL) emission spectra are measured using PL spectroscopy. Interestingly, vibrating sample magnetometry (VSM) reveals enhancements in the magnetic properties in M–H loops and it is widely used for biological applications like antibacterial activity.

Investigation of g-C3N4/Ce2(WO4)3 Nanocomposites for the Removal of Basic Dyes.

Herein, we have synthesized pristine and g-C3N4-assisted Ce2(WO4)3 via a facile hydrothermal method. The structure was confirmed with the standard JCPDS card. g-C3N4 encapsulated the crystal and reduced the size. The Raman spectra revealed the presence of Ce-O, W-O stretching and bending vibrations. Electron hole transfer facilitation and controllable recombination were altered by g-C3N4 heterojunction with cerium tungstate. Ce2(WO4)3 possessed a larger band gap. As g-C3N4 was assisted, the band gap was reduced which facilitates Ce2(WO4)3 to utilize more visible light. The prepared photocatalysts were used to investigate the model pollutant removal with visible light. The pure Janus Green B sample showed lesser efficiency, as it does not show self-degradation under light. As Ce2(WO4)3 was added, it slightly improved the efficiency as it possesses lower electron hole transfer and high recombination. Thus, g-C3N4 was composited with Ce2(WO4)3 to make heterojunctions which will enhance the photo-excited electron and hole transfer and decrease e-/h+ recombination. The rate constant values of the photocatalysts were calculated, and the system follows the first-order pseudo-kinetic model. Ciprofloxacin, a well-known antibiotic, was also used to degrade under visible light. The pure sample showed lower efficiency, and the antibiotic was reduced well with the addition of prepared photocatalysts. The modification of Ce2(WO4)3 with the optimum-level g-C3N4 facilitated electron hole charge transfer, and numerous adsorbed dye molecules on the photocatalyst surface made 0.1 g g-C3N4-Ce2(WO4)3 a plausible photocatalyst for the water remediation process.

Investigation of Structural, Morphological and Luminescent Features of Eu<sup>3+</sup> Activated Molybdate Based Phosphor for W-LED Applications

In the present work, NaBi(MoO4)2 (NBM) phosphor has been successfully synthesized by doping 1.0 mol% of Eu3+ via the conventional solid state reaction technique. The undoped synthesized NBM sample and 1.0 mol% Eu3+ doped phosphor were characterized to explore crystal structure, morphology, photoluminescence (PL) and colorimetric properties using various characterization techniques. The structural properties were analysed via x-ray diffraction and diffraction peaks were compared with the standard JCPDS (card no. 79-2240) pattern. The morphological studies of the sample have been done through FE-SEM micrograph. From the photoluminescence emission spectra, it has been observed that an intense peak was obtained in the at 615 nm under blue excitation. Colorimetric property of 1.0 mol% of Eu3+ doped NBM phosphor has been investigated and traced in the red region with high color purity of 92.79%. The aforementioned characteristics demonstrate that the NaBi(MoO4)2: 1.0Eu3+ phosphor has great potential in the field of w-LED applications.

BLUE CRAB SHELL WASTE VALORIZATION AS A SOURCE OF HYDROXYAPATITE FOR BIOCOMPATIBLE DENTAL IMPLANT COATING FABRICATION

In the presented work, the effect of hydroxyapatite/polycaprolactone (HAp/PCL) ratio and the immersion/withdrawal speed on the corrosion rate and antibacterial properties of Ti-6Al-4V ELI dental implant coating was investigated. Ti6Al-4V ELI implants are coated with different HAp-PCL ratios and immersion speeds. The functional groups of product hydroxyapatite were confirmed using the HAp standard JCPDS no. 09-0432, with crystallinity of 88.32% and ratio Ca/P at 2.12. The result shows that the higher concentrations of hydroxyapatite result in the decrease of corrosion rate and increased antibacterial activity reflected in larger inhibition zones. Additionally, the higher immersion and withdrawal speeds during dip-coating lead to lower corrosion rates. Furthermore, decreased corrosion rates may enhance the antibacterial properties of HAp-PCL coatings. These results demonstrate that the HAp/PCL composite can be considered as a prospective candidate for dental implant Ti-6Al-4V ELI coating.

Tb-doped MgAl2O4 phosphors: A study of structural and luminescence characteristics

In the MgO–Al2O3 system, magnesium aluminate spinel (MgAl2O4) is a technologically significant compound due to its unique properties, including a high melting point, low thermal conductivity, excellent thermal shock resistance, chemical inertness, and robust mechanical strength. This compound has diverse applications in refractory materials, catalyst supports, moisture sensors, nuclear techniques, insulating materials, and even military applications. While rare-earth elements are commonly used as dopants in luminescent materials, limited research exists on doping of Tb3+ ions in magnesium aluminate. This study investigates the luminescence properties of Tb3+ doped synthesis magnesium aluminate materials, shedding light on this underexplored area. The combustion method is employed for synthesis, known for producing nano-sized powders with exceptional luminescent properties. Additionally, this study explores Sm3+ ion doping in magnesium aluminate materials and their luminescence properties. Using the combustion synthesis method, structural attributes of Tb3+−doped MgAl2O4 nanophosphors are meticulously examined. Through X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, coupled with excitation and emission spectra, a comprehensive investigation of the luminescent provide behavior at room temperature is provided. The XRD data reveal Tb3+ doped MgAl2O4 phosphors exhibit a single phase with face centred cubic structure belonging to the Fd3m‾ space group, consistent with the standard JCPDS files (No. 21–1152). Excitation and emission spectra offer valuable insights into the energy transitions within the Tb3+−doped MgAl2O4 phosphors. Furthermore, the study explores the effects of varying Tb3+ ion concentrations on the luminescent properties, revealing an optimal doping concentration of 5 wt% Tb for maximizing emission intensity. Concentration quenching, primarily attributed to dipole-dipole (d-q) interactions, is observed at higher Sm3+ concentrations. In conclusion, this research enhances our understanding of rare-earth ion doping in luminescent materials and highlights the potential applications of Tb3+−doped MgAl2O4 nanophosphors, which offer promise for various technological applications, including lighting and displays.

Effectiveness of bimetallic ZnO-B2O3 nanoparticles produced by Streptomyces gancidicus as prospective antifungal agents and therapeutic nutrients to enhance pea plant immunity against damping off-causing Pythium irregulare: in vivo and in vitro investigations

AbstractPythium irregulare (P. irregulare) is one of the soil-borne pathogens that is the primary cause of damage to several plants each year. The novelty and originality of this work were the ability of Streptomyces gancidicus (S. gancidicus OR229936) to synthesize bimetallic zinc oxide-boron oxide nanoparticles (ZnO-B2O3 NPs) for reducing P. irregulare growth and safeguarding pea plant from damping off disease. The produced bimetallic ZnO-B2O3 NPs’ XRD results highlighted the ZnO diffraction peaks at 2Ɵ = 27.50°, 31.15°, 45.15°, 56.89°, 67.98°, and 75.25°, which are complemented by the standard card JCPDS number 361451 and correspond to (002), (101), (102), (110), (103), and (201) Bragg’s reflections. Along with the standard card JCPDS number 300019, they additionally include the B2O3 NP diffraction peaks at 2Ɵ = 15.25°, 28.69°, 31.99°, and 41.28°. Bimetallic ZnO-B2O3 NPs were tested against P. irregular for their antifungal activities. The findings indicated that ZnO-B2O3 NPs exhibited potential anti P. irregulare activity, with an inhibition zone of 33 mm at a concentration of 1000 µg/mL and a promising MIC of 0.01 µg/mL. Bimetallic ZnO-B2O3 NPs (0.01 ppm) application appeared to significantly lessen the severity of the pea post-emergence damaging off disease by 10% and to provide significant protection by 88%. In comparison to fungicide (difenoconazole 25%) treatments, all metabolic resistance indicators significantly enhanced after the usage of bimetallic ZnO-B2O3 NPs, ZnO NPs, and B2O3 NPs with ethyl acetate extract of S. gancidicus. The beneficial impacts of the bimetallic ZnO-B2O3 NPs, ZnO NPs, and B2O3 NPs have been broadened to increase the enzyme activities of peroxidase (POD) and polyphenol oxidase (PPO) in both healthy and infected pea plant in comparison to control. Reduction of Malondialdehyde content (MDA) in response to S. gancidius filtrate, bimetallic ZnO-B2O3 NPs, ZnO NPs, B2O3 NPs, and difenoconazole by 41.68%, 36.51%, 26.15, 26.15, and 15.25%, respectively. Also, contents of H2O2 in infected pea plant were diminished by 50%, 45%, 40%, 37.5%, and 22.5% at bimetallic ZnO-B2O3 NPs, S. gancidicus filtrate, ZnO NPs, difenoconazole, and B2O3 NPs comparing to P. irregular-infected pea plant is strong evidence to induce disease recovery. The application of bimetallic ZnO-B2O3 NPs seems to be a significant approach to relieve the toxic influences of P. irregulare on infected pea plant as green and alternative therapeutic nutrients of chemical fungicides.

Thermoluminescence studies of Sm3+ doped ZnB2O4 phosphor

Solid-state reaction method was used to prepare the rare earth Sm3+ doped ZnB2O4 phosphors. The structural characterization of Sm3+ doped ZnB2O4 samples was recorded by X-ray diffraction (XRD) technique. A single phase structure similar to the standard JCPDS files-39-1126 was recorded using XRD. The graph plotted between TL intensity a nd temperature for different UV dose was recorded. The highest TL intensity was recorded for 20 minutes of UV dose. On further increase in the exposure dose, decrease in TL intensity was observed. The thermo-luminescence was recorded with varying percentage of Sm3+. The at most TL intensity was obtained with 3 mol% of Sm3+. The thermo-luminescence spectra of ZnB2O4 and Sm3+ doped ZnB2O4 phosphors were also studied.

Effect of precursors on ZnO nanoparticles to enhance the level-III ridge details of LFPs and anti-counterfeiting applications

Comparative analysis for the combustion-based synthesis of zinc oxide nanoparticles (NPs) utilizing various precursors of zinc was reported. l-ascorbic acid extraction was used as a fuel for the combustion process. The sizes, morphologies, structural details and purity of samples were examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffractometry (XRD). XRD pattern matches with the standard JCPDS card of ZnO with good crystallite size. The average crystallite size of the NPs was confirmed the nano-regime. Variations in morphological structures and the energy band gap variation with the change in precursors was reported. Using a powder-dusting technique, on separate surfaces, level-III features of the fingerprints produced by these NPs without any background noise. The suggested powder composition was easy to make and effective for producing latent finger prints on a variety of dry and wet surfaces. In the area of counterfeit prevention, the fluorescent ink has several potential applications. Invisible security ink was developed for anti-counterfeiting applications based on the UV fluorescence feature of ZnO NPs. The fluorescent invisible security ink for screen printing was evaluated and proved to be stable on a variety of microporous papers. The new strategy adopted here lowers the cost of ink by using rare earth free ZnO NPs.

Green Synthesis of Zinc Oxide Nanoparticles Using Cymbopogon citratus Extract and Its Antibacterial Activity.

Excessive use of antimicrobial medications including antibiotics has led to the emerging menace of antimicrobial resistance, which, as per the World Health Organization (WHO), is among the top ten public health threats facing humanity, globally. This necessitates that innovative technologies be sought that can aid in the elimination of pathogens and hamper the spread of infections. Zinc oxide (ZnO) has multifunctionality owing to its extraordinary physico-chemical properties and functionality in a range of applications. In this research, ZnO nanoparticles (NPs) were synthesized from zinc nitrate hexahydrate, by a green synthesis approach using Cymbopogon citratus extract followed by characterization of the NPs. The obtained X-ray diffraction peaks of ZnO NPs matched with the standard JCPDS card (no. 89-510). The particles had a size of 20-24 nm, a wurtzite structure with a high crystallinity, and hexagonal rod-like shape. UV-Vis spectroscopy revealed absorption peaks between 369 and 374 nm of ZnO NPs synthesized from C. citratus extract confirming the formation of ZnO. Fourier transform infrared confirmed the ZnO NPs as strong absorption bands were observed in the range of 381-403 cm-1 corresponding to Zn-O bond stretching. Negative values of the highest occupied molecular orbital-lowest unoccupied molecular orbital for ZnO NPs indicated the good potential to form a stable ligand-protein complex. Docking results indicated favorable binding interaction between ZnO and DNA gyrase subunit b with a binding energy of -2.93 kcal/mol. ZnO NPs at various concentrations inhibited the growth of Escherichia coli and Staphylococcus aureus. Minimum inhibitory concentration values of ZnO NPs against E. coli and S. aureus were found to be 92.07 ± 0.13 and 88.13 ± 0.35 μg/mL, respectively, at a concentration of 2 mg/mL. AO/EB staining and fluorescence microscopy revealed the ability of ZnO NPs to kill E. coli and S. aureus cells. Through the findings of this study, it has been shown that C. citratus extract can be used in a green synthesis approach to generate ZnO NPs, which can be employed as alternatives to antibiotics and a tool to eliminate drug-resistant microbes in the future.

Structural and photoluminescence properties of Sm3+ ions doped strontium yttrium tungstate phosphors for reddish-orange photonic device applications

In the present research work, Sm3+ ions doped Strontium Yttrium Tungstate (Sr9Y2W4O24) phosphors entitled to emit reddish-orange light have been synthesized using the conventional solid-state reaction method and analyzed their structure and phase using X-ray diffraction (XRD) patterns. The diffraction peaks of the Sr9Y2W4O24 phosphor matches very well with the standard JCPDS pattern with card no. 49-0568. The morphological behaviour of the as-synthesized phosphor has been studied using scanning electron microscopy (SEM). Different vibrational bands present in the titled phosphor have been examined using Fourier Transform Infrared (FT-IR) spectroscopy. The optical band gap values of the as-synthesized phosphors have been measured using diffuse reflectance spectra (DRS). The photoluminescence (PL) spectral features recorded for Sm3+ ions activated Sr9Y2W4O24 phosphor under 405 nm excitation reveal strong visible reddish-orange emission at 604 nm pertaining to the 4G5/2 → 6H7/2 transition of Sm3+ ions. Also the PL spectra show concentration quenching at 2 mol% of Sm3+ ions doped in to them. From the recorded PL spectra, the CIE chromaticity coordinates estimated for Sr9Y2W4O24:2.0mol% of Sm3+ phosphor are falling in deep visible reddish orange region. The PL decay spectral profiles recorded at 604 nm emission under 405 nm excitation are showing double exponential behavior and the experimental lifetimes are found to be decreasing with increase in Sm3+ ions concentration in the assynthesized phosphors. The temperature-dependent PL (TD-PL) measurements demonstrate relatively better thermal stability for the as-synthesized phosphor. All the investigations carried out finally allows us to contemplate the suitability of Sm3+ ions doped Sr9Y2W4O24 phosphor for reddish-orange photonic device applications.

Structural, vibrational and magnetic properties of ytterbium (Yb) and nickel (Ni) substituted BFO particles

In this work, synthesis of Yb and Ni substituted BFO particles have been carried out successfully using sol–gel approach. The particles obtained are of good crystalline nature. With the increasing doping concentration, the crystallite size also has been found to get decreased. It has been observed that for sample x = 0.08 the crystallite size suddenly gets increased. This can be due to the generation of some secondary impurity phase at higher doping concentration. The average crystallite size calculated is about 28.1 nm. The obtained XRD pattern matches perfectly with the standard JCPDS card number 71–2494. A dense morphology of spherical grain size is visible. The sizes of the grains are found to be in the range which is less than 100 nm. Reduction in grain size has been obtained for x = 0.02 samples. Higher surface area for active sites is resulted from reduced grain size. There is availability of 13 Raman active modes. All these modes have rhombohedrally distorted perovskite form and they are within the R3C space group. The value of the spontaneous magnetization (Ms) has been found to be escalating from 0.206 emu/g to 0.789 emu/g, due to doping of Yb and Ni. It has also been observed that, the remnant magnetization (Mr) value has escalated from 0.020 emu/g to 0.052 emu/g due to rise in the doping concentration in the synthesized BYFNO particles. Enhancement in other magnetic parameters like coerciviety and remnant magnetization have also been observed. Incorporation of magnetic Ni ions with Yb substitution can be the major reason for enrichment in the magnetic properties.

Investigation of structural, optical, morphological, photoluminescence and antimicrobial properties of SrAl2O4:Eu2+ nanophosphor by using urea fuel combustion method

In the present study, the Sr1−xAl2O4:Eux (x = 0.00, 0.01, 0.03, 0.05, 0.07, and 0.09) phosphor were synthesized by urea fuel combustion method at 580 °C temperature with very high brightness and long after glow. The structural studies carried out using XRD technique shows that the sample is single phased in nature and it gets crystallized into monoclinic phase with standard JCPDS 34-0379 card. The oxide formation was examined using FTIR technique. UV–Visible spectroscopy has been used to study the optical band gap of material, it’s value in the current case, Sr1−xAl2O4:Eux (x = 0.05) is 3.78 eV. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirm the formation of nano particle, with average particle size around 6–25 nm. The elemental composition was confirmed by using Energy Dispersive X-ray (EDX) technique. The photo-luminescence study revealed that it gives broad emission spectra using excitation wavelength λex = 365 nm. It is observed that the Sr1−xAl2O4:Eux (x = 0.05) phosphor give maximum emission intensity and it can be regulated as green (0.23, 0.49) emission with the colour temperature 3224 K, CRI 78, and colour purity 60.69%. The spectra are intense and lie in the visible range. The green lights can regulate the circadian rhythm through melatonin, and it is also suitable for green LED and other optoelectronic devices. The Sr1−xAl2O4:Eux (x = 0.00 and 0.05) phosphor behaves like eco-materials, because nano particles of Sr1−xAl2O4:Eux (x = 0.05) does not show antimicrobial activity.

Synthesis and photoluminescence properties of a novel green-emitting LiYGeO4 :Tb3+ long afterglow phosphor.

A new green luminescent phosphor, Li(Y1-x Tbx )GeO4 , was prepared using a high-temperature solid-phase method. The X-ray diffraction (XRD) measured spectrum agreed well with the standard card JCPDS No. 02-3479, indicating that it is a quaternary compound belonging to the space group of Pnma(62) with an orthogonal crystalline phase; the excitation and emission spectra measured using the phosphor spectrometer showed that it can be effectively excited by near-ultraviolet light at 378 nm and blue light at 482 nm, and produced excellent strong emission of green light at 550 nm. The afterglow test results show that the sample had a good long afterglow effect at lower doping concentrations; the thermal stability test results showed that its thermal burst activation energy ΔE ≈ 0.37 eV had its excellent thermal stability. The rare earth Tb3+ -doped green phosphor, LiYGeO4 :Tb3+ , has potential applications in household lighting, medical therapy, and optical storage.

Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

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).