Photoluminescence Emission Spectra Research Articles

Photoluminescence studies of different types of feldspars and the implications to the dating application using a Raman system

In recent years, the infrared photoluminescence (PL) of feldspar has been explored for geological dating because it offers a great increase in signal intensity with increasing radiation dose. However, a comprehensive understanding of the PL emission spectra of different types of feldspar minerals remains poorly understood and the uncommonly available instruments have hindered its research. In this study, we investigated PL characteristics (e.g., emission spectra and the dependence of PL emission on irradiation dose) of single-crystal alkali and plagioclase feldspars using a commercial Raman microscope instrument configured to excite samples with 532 and 785 nm lasers. The results show that despite being sample-dependent, 2–3 PL bands peaking at ∼2.10 eV (590 nm), 1.75 eV (710 nm), and 1.43 eV (865 nm) under 532 nm laser excitation, and 0–2 peaks ranging from ∼1.44 eV (863 nm) to ∼1.34 eV (925 nm) under 785 nm laser excitation, are broadly observed. These variations in PL bands may be attributed to subtle differences in chemical composition and crystal structure among the feldspar minerals. The sensitivity of PL emission to irradiation dose varies greatly depending on feldspar types and peak positions. The PL intensities of the peaks at ∼1.43 eV (865 nm) are particularly sensitive in K-feldspar, demonstrating their potential applicability for dating applications. Additionally, solar bleaching experiments demonstrate that PL signals of these peaks can be effectively reset by 1.5 h of solar exposure. The dose-response curves obtained using 860–870 nm PL signals of K-feldspar conform to a relationship of a single saturating exponential function between the signal and irradiation dose. Furthermore, this study demonstrates that a commonly available Raman system can be utilized for PL measurements of single grains.

Exploring the structural, optical and photoluminescence of novel terbium-doped barium borosilicate glasses for high-performance technologies

The production process involved the use of the melt-quenching approach to produce a series of barium borosilicate glasses with the specific chemical formula 55B2O3+(26-x)BaO+12SiO2+7Na2O + xTb4O7, where x = 0, 0.5, 1, 2, and 3 mol%. X-ray diffraction (XRD), Raman spectroscopy, optical absorption, and photoluminescence spectra measurement were used to examine the prepared samples. X-ray diffraction revealed the non-crystalline character of the assembled samples. The Raman spectroscopy revealed that the incorporation of Tb4O7 into borosilicate glasses induced alterations in their structure. As the doping of Tb3+ ions increases, the density and molar volume of the glasses under investigation increase. Furthermore, the ion concentration and field strength increase while the polaron radius and inter-ionic distance decrease. The glass optical absorption spectra showed five peaks in the wavelength range from 300 nm to 2000 nm: 5L10, 5D3, 5D4, 7F(0, 1, 2), and 7F3, attributed to Tb3+ ion electronic transitions. In addition, optical parameters like optical energy gap, Urbach energy, refractive index, molar refractive index, reflection loss, electronic polarizability, and optical transmission coefficient were computed. Terbium-doped borosilicate glasses had a decreased optical energy gap and an improved refractive index. Photoluminescence spectra were excited at 325 nm and showed five peaks in the range of 400–750 nm. Photoluminescence (PL) emission spectra exhibit distinct peaks in the visible range.

Exploring single rare earth doped nanophosphor for efficient white emission through codoping of Na+ and Bi3+ ions into Dy3+ activated LaPO4

Using the simple hydrothermal technique, high-purity nanocrystalline Na+ and Bi3+ co-doped Dy3+ activated LaPO4 was effectively prepared. The structural characterisation of the prepared samples was carried out using XRD, EDS, SEM and FTIR analysis. The existence of Na+, Dy3+, La3+, P5+, O2– and Bi3+ was demonstrated using EDS analysis. The direct band gap value of 4.72 eV is obtained from UV visible absorption spectrum and infer that the doped samples are suitable for optical applications. The photoluminescence excitation spectrum monitored at 474 nm and 570 nm emission, the Na+ and Bi3+ co-doped Dy3+ activated LaPO4 exhibit narrow, and intense characteristics f-f peak of Dy3+ ion at 349 nm, 363 nm, 386 nm and 452 nm. Photoluminescence emission spectrum, monitored under 349 nm, 363 nm and 386 nm shows high intense sharp blue emission peaks of Dy3+ with stark splitting at 475 nm, 478 nm, and 486 nm, yellow emission at 571 nm and 580 nm and a very feeble peak at 658 nm in the red region. When the sample is excited at 452 nm only a yellow band is present. Since the intensity of blue and yellow emission in this host matrix is so high and nearly equal, it is appropriate for cool white emission under 350 nm, 363 nm and 386 nm (near UV) excitation and under 452 nm (blue LED) excitation the prepared phosphor may emerge as highly efficient warm white light emitter suitable for general solid-state lighting applications, which can be further confirmed by CIE chromaticity analysis of the prepared sample. In photoluminescence excitation and emission spectra intensities of peaks of the samples with Bi3+ are more intense, this confirms the positive impact of co-doping of Bi3+ into the sample. The Q value from the Dexter’s formula is calculated as an average of 6.4 and is very close to 6 indicates that the interaction is dipole − dipole, which causes the non-radiative energy migration among the Dy3+ ions in the sample. The lifetime of characteristic yellow emission of Dy3+ in the Na+ and Bi3+ co-doped Dy3+ activated LaPO4 host matrix monitored under 350 nm is calculated as 0.642 ms from decay analysis, fitted by a bi-exponential function. The results support the idea that co-doping of Bi3+ and Na+ into the LaPO4:Dy3+ matrix could emerge as a potential white light emitting phosphor for phosphor-converted white LED application.

Hexagonal rod-like Eu3+ doped CaMoO4 phosphors: Structural, photoluminescence and photometric properties for display device applications

A multicolored LED illumination device is a compact, durable, easy to obtain color-adjustable output illumination source. It is frequently utilized in the domains of room illumination and exterior displays. However, the advancement of multicolor LEDs has been hampered by the rise in price and the fall in luminous efficacy while changing illumination colors. In the present investigation we have prepared intense red emitting Eu3+ doped CaMoO4 phosphor nanopowders via simple solid-state reaction technique. The powder X-ray diffraction (PXRD) studies reveal the crystalline nature of the samples with scheelite–type mono phase tetragonal structure with I41/a space group. The band gap (Eg) energy values were estimated and found to range between 4.63-5.32 eV. Scanning electron microscopy (SEM) studies reveled the hexagonal rod-like structures with different Aloe Vera gel concentrations. The particle size was found to be around 40 nm. The vibrational modes of the prepared powders were evaluated by using Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. It was observed from the results that, there were 26 vibrational modes of CaMoO4 (Γ=3Ag + 5Au + 5Bg + 3Bu + 5Eg + 5Eu) 8 of which (4Au and 4Eu) were infrared active and 13 (Ag, Bg, and Eg) are Raman active. Photoluminescence (PL) emission intensity increases up to 5 mol% of Eu3+ ions load and subsequently it declines due to the concentration quenching phenomenon and effective energy transfer from Mo-O charge transfer band (CTB) to 5D0 levels of Eu3+. It was noticed from PL emission spectra that, four intense peaks located at 5D0 → 7F1 (590 nm), 5D0 → 7F2 (613 nm), 5D0 → 7F3 (654 nm), 5D0 → 7F4 (702 nm) of Eu3+ respectively. The Commission International de I'Eclairage (CIE) diagram indicates the red color emission and average correlated color temperature (CCT) value was found to be 2050 K. Further, the external quantum efficiency (QE) and color purity (CP) were calculated to check the phosphor efficiency and found to be 92% and 72% respectively. The present investigation opens up a new avenue in the fabrication of low-cost display devices with high color purity and luminous efficacy.

The photoluminescence studies of Gd3+/Tb3+ co-doped xerogels and nano-glass-ceramics dedicated for green-emitting devices

In this work, we reported the results of photoluminescent and structural investigations of Gd3+/Tb3+ co-doped silicate xerogels as well as derivative SiO2-LaF3 nano-glass-ceramics. The molar ratio of appropriate acetates used during the synthesis, i.e., La(AcO)3:Gd(AcO)3:Tb(AcO)3 was fixed to x:(0.95-x):0.05. Based on XRD measurements, the crystallization of hexagonal LaF3 nanophase was verified without any admixture of GdF3 phase, even for samples with La3+:Gd3+ molar ratio ≤1. The optical characterization of fabricated Gd3+/Tb3+ co-doped sol-gel materials involved the registration and analysis of photoluminescence excitation (PLE) and emission spectra (PL), as well as the decay curves for the 6P7/2 (Gd3+) and the 5D4 (Tb3+) excited levels. Upon excitation at λex = 275 nm wavelength, the fabricated sol-gel samples revealed the series of emission lines assigned to the electronic transitions from both dopants, i.e., Gd3+ and Tb3+, indicating apparently the occurrence of Gd3+/Tb3+ energy transfer process (ET). The photoluminescence measurements comprehensibly proved the competitiveness between Gd3+ and Tb3+ ions to be entered into LaF3 fluoride nanocrystal lattice, formed during annealing of as-prepared xerogels. Based on the recorded PL spectra for fabricated sol-gel samples, some chromatic parameters were calculated, i.e., chromaticity coordinates (CIE), correlated color temperatures (CCT), and color purities (CP). The prepared Gd3+,Tb3+ co-doped samples are able to emit green light with CCT values in a range from 5967 K to 6291 K, and high CP reached 70 %, which predispose them for use as efficient constituents for developing green-emitting devices.

Assembly of functional carboxymethyl cellulose/polyethylene oxide/anatase TiO2 nanocomposites and tuning the dielectric relaxation, optical, and photoluminescence performances

Nanocomposite films consisting of carboxymethyl cellulose, polyethylene oxide (CMC/PEO), and anatase titanium dioxide (TO) were produced by the use of sol-gel and solution casting techniques. TiO2 nanocrystals were effectively incorporated into CMC/PEO polymers, as shown by X-ray diffraction (XRD) and attenuated total reflectance fourier transform infrared (ATR-FTIR) analysis. The roughness growth is at high levels of TO nanocrystals (TO NCs), which means increasing active sites and defects in CMC/PEO. In differential scanning calorimetry (DSC) thermograms, the change in glass transition temperature (T g) values verifies that the polymer blend interacts with TO NCs. The increment proportions of TO NCs have a notable impact on the dielectric performances of the nanocomposites, as observed. The electrical properties of the CMC/PEO/TO nanocomposite undergo significant changes. The nanocomposite films exhibit a red alteration in the absorption edge as the concentration of TO NCs increases in the polymer blend. The decline in the energy gap is readily apparent as the weight percentage of TO NCs increases. The photoluminescence (PL) emission spectra indicate that the sites of the luminescence peak maximums show slight variation; peaks get wider, while their intensities decrease dramatically as the concentration of TO increases. These nanocomposite materials show potential for multifunctional applications including optoelectronics, antireflection coatings, photocatalysis, light emitting diodes, and solid polymer electrolytes.

Fully quantum-kinetic theory of the steady-state cooperative photoluminescence from two near-identical emitters

We have developed a theory of cooperative photoluminescence from two closely spaced particles using the density matrix method. The theory provides modelling of the photoluminescence excitation and emission spectra by nonidentical quantum emitters entangled by the dipole–dipole interaction in presence of a cw laser beam. It is shown that the excitation spectra agree with all currently known experiments with pairs of coherently coupled organic molecules in thin solid layers. The modelling was performed with the use of the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchies for reduced density matrices and correlation operators of the quantum emitters and photonic subsystems. This method gives a straightforward way to describe the dipole–dipole coupling and entanglement of the emitters. We have also calculated the emission spectra to demonstrate the expected spectral patterns.

Microstructural evolution and luminescence properties of multi-excitable cubic-ZrW2O8:Dy3+ nanorods for white light applications

ZrW2O8 nanorods doped with various concentrations of Dy3+ ions (5 - 15 mol%) showing excellent photoluminescence (PL) properties were synthesized by the facile hydrothermal method for white light applications. The products were comprehensively analyzed using a range of structural, morphological, and optical techniques. The optical studies were conducted by utilizing UV-visible and photoluminescence spectrophotometers. The photoluminescent emission spectra exhibit two prominent peaks at wavelengths of 479 nm and 572 nm, along with a less intense peak at 661 nm when subjected to excitations at wavelengths of 286 nm and 352 nm, and a highly dominating yellow emission with a faint red emission was obtained at 452 nm excitation. The almost constant value Y/B intensity ratios, lifetime values, CIE coordinates, and CCT values suggest that the obtained nanophosphor can be effectively employed in white light-emitting diodes (WLEDs) and various other lighting devices.

Structural and Spectroscopic Analysis of Reddish-Orange Emitting (Y1−x)2WO6:xEu3+ (0 ≤ x ≤ 0.11) Nanophosphors for Anti-Counterfeiting Application

Exploring luminescent materials that meet the necessary specifications for anti-counterfeiting applications has been the focus of extensive research. In this study, we delve into a double perovskite-structured material, (Y1−x)2WO6:xEu3+ (0 ≤ x ≤ 0.11), synthesized via a chemical combustion method. The crystallographic studies using the X-ray diffraction pattern confirm the crystallization of the nanophosphors into the monoclinic phase with a P2/c space group. The Raman and Fourier transform infrared spectroscopy studies provide insights into the nature of chemical bonding within the material. UV visible spectra are analysed to determine the optical energy gap. Notably, the photoluminescence emission spectra of the Eu3+ incorporated phosphors exhibit a distinct emission peak at 609 nm, corresponding to the 5D0 → 7F2 electric dipole transition of the Eu3+ ions. The optimal photoluminescence intensity is observed for the x = 0.07 nanophosphor, with estimated chroma coordinates of (0.500, 0.316), placing it in the reddish-orange region of the chromaticity diagram. The incorporation of Eu3+ enhances magnetization, attributed to the presence of Eu3+ ions in the 7F2 state. The luminance stability is a critical factor for long-term performance, the x = 0.07 phosphor was analysed under rigorous physical and chemical testing and is found to be stable, making it a favourable candidate as a luminescence pigment for anti-counterfeiting applications.

Synthesis and erudite insight into the structural, luminescence and thermal sensing characteristics of Sm3+ incorporated [formula omitted]-BaB2O4 novel phosphors

In this paper, we have presented the comprehensive characterization of red-light-emitting novel β-BaB2O4:xSm3+ (x = 0.5, 0.75, 1, 1.5, and 2 mol%) phosphor samples synthesized by making use of solid-state reaction method. The XRD patterns verified the successful synthesis and in-depth analyses were carried out to explore the structural, luminescence, and thermal properties. Notably, the introduction of Sm3+ through doping did not result in any substantial alterations in the crystal structure. Photoluminescence (PL) emission spectra exhibited 4 distinct peaks for 401 nm excitation. Out of these 4 peaks, the prominent peak was present at 601 nm, attributed to the magnetic dipole-allowed transition 4G5/2 → 6H7/2. The colorimetric analysis revealed the correlated color temperature (CCT) to be around 1700 K, accompanied by 99.9 % colour purity. The optimal doping concentration, before luminescence quenching, was identified as 1 mol%, with multipole-multipole interactions identified as the predominant quenching mechanism. Diffuse reflectance spectroscopy (DRS) studies on β-BaB2O4:1%Sm3+ confirmed characteristic peaks corresponding to Sm3+ transitions, revealing an ionic bonding nature between Sm3+ and the host. Also, the direct optical band gap was determined to be 5.62 eV. Furthermore, the optimized phosphor demonstrated exceptional temperature-dependent photoluminescent (TDPL) properties, exhibiting a negligible (∼5 %) decrease in emission intensity for prominent peaks even at 440 K. Overall, the phosphors displayed high activation energy, significant thermal stability, and thermal sensing properties, making them promising candidates for various optoelectronic applications.

Oxygen evolution reaction kinetics and photoluminescence studies of zinc stannate (ZnSnO3/Zn2SnO4) nanoparticles synthesized via [formula omitted] mediated route

A groundbreaking method utilizing Aloebarbadensismiller gel to synthesize novel zinc stannate nanoparticles in two distinct phases, followed by calcination at 600 °C, has been developed. Structural, optical, and electrochemical analyses were meticulously conducted to explore the impact of phase variation. X-ray diffraction confirmed the formation of face-centered perovskite and inverse spinel cubic structures for ZnSnO3 and Zn2SnO4 nanoparticles respectively, with irregular sizes and shapes observed in both phases. Energy-dispersive X-ray spectroscopy confirmed their purity. Tauc’s plot revealed direct energy band gaps of 3.45 eV and 3.4 eV for ZnSnO3 and Zn2SnO4 respectively, with photoluminescence emission spectra displaying distinct peaks at 646 nm and 647 nm. The study identified higher defect levels in the inverse spinel structure. Notably, the synthesized nanoparticles exhibited promising characteristics for light-emitting diodes and display technology, with color-correlated temperatures (6810 and 6695 K) suggesting their potential application. Furthermore, the nanoparticles demonstrated remarkable performance in oxygen evolution reaction (OER) studies, with low overpotentials (η10) in the range of 269 mV and 273 mV along with a minimal Tafel slope of 76 mV dec−1 and stable electrochemical behavior over 45 h at a current density of 20 mA/cm2, indicating their efficacy as electrocatalysts. The current work unveils the novel synthesis of zinc stannate nanoparticles through an Aloebarbadensismiller gel, a method that stands out for its eco-friendly and cost-effective nature. We delve into uncharted territory by investigating these nanoparticles’ oxygen evolution reaction kinetics and photoluminescence properties, shedding light on their potential applications in energy conversion and sensing technologies. This pioneering study contributes to the understanding of zinc stannate nanoparticles’ behavior, paving the way for transformative advancements in various fields.

Luminescence studies and Judd Ofelt parameterization of Dy3+ activated La2(WO4)3 yellow phosphor

The synthesis and detailed luminescence studies of a series of La2-xDyx(WO4)3 (x = 0.02, 0.1, 0.2, 0.4, 0.6, 0.8) phosphors synthesized via microwave-assisted co-precipitation technique is reported in this paper. The XRD analysis confirmed that the phosphors were crystalized in a monoclinic structure with space group C2/c and FTIR analysis identified the characteristic vibrational modes. Morphological studies were conducted using FESEM analysis, and the EDS technique substantiated the effective incorporation of Dy3+ ions in La2(WO4)3. The photoluminescence excitation and emission spectra of varying concentrations of Dy3+ ions were recorded and an optimum concentration of 10% exhibited the highest intensity. The emission spectra of all phosphors were dominated by peaks at 484 nm and 574 nm. The radiative properties were evaluated using Judd-Ofelt analysis and the JO intensity parameters followed the trend Ω2 > Ω6 > Ω4. The gradual decrease in the decay lifetime value of 4F9/2 excited level with an increase in doping concentration elucidates concentration quenching phenomena due to dipole – quadrupole interaction. The emission data were also analyzed by calculating CIE coordinates and concluded that Dy3+ doped La2(WO4)3 phosphors have potential applications in yellow light generation.

Exploring innovative applications of Sr2MgSi2O7:Fe3+ luminescent system in surface-triggered fingerprint divergence and cheiloscopy screening

In this study, we employ a cost-effective combustion method to synthesize (1–11 mol %) Fe3+ doped Sr2MgSi2O7 nanophosphors (SMSO NPs) and conduct a comprehensive investigation into their structural and luminescent properties. The impact of iron concentration on the structural and optical characteristics is thoroughly analysed, revealing a tetragonal crystal structure with space group P-421m through Rietveld refinement and X-ray Diffraction (XRD) patterns. Scanning electron microscopy showcases the random dispersion of agglomerated particles with non-uniform dimensionality. Energy Dispersive X-ray analysis (EDS) assesses the nominal composition of Sr, Mg, Si, Fe, and O, while X-ray Photon Spectroscopy (XPS) confirms the direct incorporation of Fe3+ ions into the SMSO lattice. Photoluminescence (PL) emission spectra exhibit a deep red emission band at 718 nm. The residual luminescence intensity of SMSO:7Fe3+ at 200 °C is 91 %. Under 365 nm UV light, the optimized SMSO:7Fe3+ NPs displays easily identifiable levels I-III fingerprints (FPs) features with good resolution and contrast. The resilient luminescence and nano-regime of the phosphor reveal well-defined type I–V groove patterns in latent lip prints (LLPs) on various non-porous surfaces, unaffected by background interference or colour distraction. This study highlights SMSO:7Fe3+ NPs as a promising option for individualizing and detecting latent fingerprints (LFPs) and lip prints (LPs).

Hydrothermal Synthesis and Characterization of WSe2 Nanosheets: A Promising Approach for Wearable Photodetector Applications.

The two-dimensional (2D) WSe2 nanostructure was successfully synthesized via the hydrothermal method and subjected to comprehensive characterization using various spectroscopic techniques. X-ray diffraction (XRD) analysis confirmed the formation of nanosheets with a hexagonal crystal structure having a space symmetry of P63/mmc. Scanning electron microscopy (SEM) images showed irregular and nonuniform morphology. The size of the 2D nanosheets was determined using transmission electron microscopy (TEM) providing insights intotheir physical characteristics. The optical spectrum analysis yielded a discernible band gap value of 2.1 eV, as determined by the Tauc equation. Photoluminescence (PL) spectra display an emission at a wavelength of 610 nm, showing a broad emission associated with self-trapped excitons. Under excitation at λexc = 360 nm, PL emission spectra displayed a distinct peak at 610 nm, demonstrating the ability of the nanostructure to emit vivid red light. Photometric analysis underscored the potential of this nanostructure as a prominent red-light source for diverse display applications. The optimized photodetection performance of a device showcases a photoresponsivity of approximately 1.25 × 10-3 AW-1 and a detectivity of around 5.19 × 108 Jones at a wavelength of 390 nm. Additionally, the quantum efficiency is reported to be approximately 6.99 × 10-3 at a wavelength of 635 nm. These findings highlight the capability of the device for efficient photoconversion at specified wavelengths, indicating potential applications in sensing, imaging, and optical communication. The combination of structural, morphological, and optical characterizations highlights the suitability of 2D WSe2 nanostructure for practical optoelectronic applications, particularly in display technologies.

Strontium oxide–Barium oxide–Aluminium oxide ternary nanocomposite: Photoluminescence and electrochemical analysis for display and supercapacitor applications

indent In the present communication, a ternary nanocomposite (NCs) of Strontium oxide (SrO), Barium oxide (BaO), and Aluminium oxide (Al2O3) were synthesized and their photoluminescence and electrochemical analysis were performed for display and supercapacitor applications. The NCs were synthesized by solution combustion method using both chemical (SBA-U) and green extract as a fuel/reducing agent (SBA-A). The synthesized sample is subjected to calcination at 600 ° C for 3 h. The Bragg reflections of the synthesized NCs can be attributed to hexagonal SrO, tetragonal BaO and spinel cubic γAl2O3. The SEM image clearly shows the presence of agglomerated irregular size and shaped NPs. The agglomeration was found to be more in SBA-U NCs rather than SBA-A NCs. The direct energy band gap was determined from UV-visible absorption spectra using Wood and Tauc’s relation. The estimated energy band gap was found to be less in SBA-A (3.81 eV) than that of SBA-U NCs (3.88 eV). Further, photoluminescence emission spectra recorded at 300 nm excitation wavelength consist of the high-intensity peak in the green region whereas satellite peaks in blue and red regions. However, the CIE plot and color-correlated temperature confirm the present synthesized NCs are promising candidates for display technology as a green phosphor material. Further, electrochemical studies were performed and the supercapacitance value was determined, which varied within the range of 97.2 to 59.6 F/g at different scan rates. Even though the fuel/reducing agent shows their effect on the intensity of photoluminescence spectra, no such variations are observed in the electrochemical studies. The synthesized samples from both methods might find an application in display and supercapacitor applications.

Room temperature ferromagnetism in undoped and Fe doped Zn3P2 nanoparticles: Structural, optical and magnetic properties

In the current study, the structural, optical, and magnetic characteristics of Fe-doped Zn3P2 nanoparticles prepared by the solid-state reaction technique with various concentrations of Fe (x = 0.00, 0.02, 0.04, 0.06, and 0.08) were investigated. Studies using X-ray diffraction (XRD) verified that all of the produced samples had a tetragonal structure without any other phase, and that the lattice parameters increased (a = 8.090 Å, c = 11.421 Å to a = 8.120 Å, c = 11.499 Å) as the amount of dopant increased. The scanning electron microscopy (SEM) performed on the sample demonstrates that the grain size is almost spherical. The size of agglomerations slightly increases with increasing dopant concentration. The results of an energy dispersive X-ray analysis (EDAX) are almost exactly what was anticipated for the atomic weight ratios. The optical bandgap of the samples went from being 1.406 eV to being 1.453 eV when the dopant concentration was raised. When excited at wavelengths of 210 nm and 240 nm, rather than 307 nm, very intensity Photoluminescence (PL) emission spectra were detected in all of the samples. Vibrating sample magnetometer (VSM) verified that magnetic moment is found to increase (0.08829 emu/g to 0.23125 emu/g) with increase of dopant concentration from 0.02 to 0.08.

Green synthesis of polyoxometalate Cu3Mo2O9 nanoparticles for efficient degradation of organic dyes under visible light irradiation and their photoluminescence

Well-constructed photocatalysts with efficient catalytic activity have attracted much attention due to their efficient visible-light absorption and superior charge separation capability. Visible-light responsive Cu3Mo2O9 nanoparticles are synthesized utilising a simple and environmentally friendly green combustion process with Butea monosperma leaf extract as a reducing agent. X-ray diffraction pattern confirms the formation of orthorhombic crystal structure of Cu3Mo2O9 NPs corresponding to space group Pnma (62). Furthermore, the synthesized NPs were characterized using FTIR, UV-DRS, PL, SEM and TEM studies. It was found that the direct energy band gap was 2.29 eV. Through photodegradation in the presence of visible light, the dye-sorbed photocatalyst exhibited excellent results. The sorbents have also been examined for recycling, and it has been observed that they maintain their effectiveness even after multiple successive runs. These substances therefore appear to have potential as efficient industrial dye wastewater remediators. Moreover, the high intensity emission in the green zone is amply confirmed by the photoluminescence emission spectra and CIE coordinates. The Latent fingerprints (LFP) are visible with the application of the powder dusting process. The synthesized CMO nanoparticles exhibit ridge patterns that are well-resolved and useful for identifying unique LFP.

Tailoring of charge carriers with deposition temperature in pulsed laser deposited BiFeO3 thin films

This research investigates the structural, topological, electrical and optical properties of pulsed laser deposited polycrystalline BiFeO3 thin films on silicon and glass substrate at varying deposition temperatures ranging from 400 °C to 700 °C. X-ray diffraction confirm rhombohedral phase and X-ray photoelectron spectroscopy reveals stoichiometric BiFeO3 films. The optical bandgap of thin films obtained from absorption spectra increases with the substrate temperature. Photoluminescence emission spectrum reveals the defects and Atomic Force Microscopy analysis bring out the surface topography and crystallinity improvement with temperature. The charge transport studies reveal a transition in conductivity from n-type at lower deposition temperature to p-type at higher deposition temperature, attributed to oxygen and bismuth vacancies respectively. The intricate understanding of conductivity tuning and the leaky nature of BiFeO3 thin film opens avenues for applications in non-volatile memories, particularly neuromorphic devices.

MgAl Oxide Coatings Modified with CeO2 Particles Formed by Plasma Electrolytic Oxidation of AZ31 Magnesium Alloy: Photoluminescent and Photocatalytic Properties

MgAl oxide coatings composed of MgO and MgAl2O4 phases were doped with CeO2 particles via plasma electrolytic oxidation (PEO) of AZ31 magnesium alloy in a 5 g/L NaAlO2 water solution. Subsequently, particles of CeO2 up to 8 g/L were added. Extensive investigations were conducted to examine the morphology, the chemical and phase compositions, and, most importantly, the photoluminescent (PL) properties and photocatalytic activity (PA) during the photodegradation of methyl orange. The number of CeO2 particles incorporated into MgAl oxide coatings depends on the concentration of CeO2 particles in the aluminate electrolyte. However, the CeO2 particles do not significantly affect the thickness, phase structure, or surface morphology of the coatings. The PL emission spectrum of MgAl oxide coatings is divided into two bands: one in the 350–600 nm range related to structural defects in MgO, and another much more intense band in the 600–775 nm range attributed to the F+ centres in MgAl2O4. The incorporated CeO2 particles do not have a significant effect on the PL intensity of the band in the red spectral region, but the PL intensity of the first band increases with the concentration of CeO2 particles. The PA of MgAl/CeO2 oxide coatings is higher than that of pure MgAl oxide coatings. The MgAl/CeO2 oxide coating developed in aluminate electrolyte with a concentration of 2 g/L CeO2 particles exhibited the highest PA. The MgAl/CeO2 oxide coatings remained chemically and physically stable across multiple cycles, indicating their potential for applications.

Biosynthesis of PbO nanoparticles via Adhatoda vesica (Justicia adhatoda) leaves extract for antimicrobial and photocatalytic applications

Research applications in biology and the environment can benefit greatly from nanoscience and nanotechnology. Aqueous leaf extract of Adhatoda vesica (AV) mediated the formation of lead oxide (PbO) nanoparticles in this study. A XRD analysis confirmed that the lead oxide nanoparticles (PbO NPs) synthesized from leaves extract have a crystalline structure. UV–vis spectroscopy study of colloidal PbO nanoparticles absorption revealed the greatest absorption bands, and the photoluminescence (PL) emission spectrum revealed a broad nature of visible emission peaks with high surface defects. By analyzing PbO nanoparticles using the fourier transform infrared method (FTIR), the leaf extract demonstrated the presence of functional peaks. It was evident from the SEM images that most of the PbO NPs had a spherical, irregular sponge-like shape. Additionally, the PbO nanostructures were tested for their antibacterial activity against Escherichia Coli, and a high level of antibacterial activity was observed, indicating their suitability for antimicrobial applications. PbO NPs have been evaluated for photocatalytic degradation of methylene blue dye (MB) under UV irradiation and have produced indications that the synthesized material is suitable for photocatalytic degradation. The Adhatoda vesica is used as medicine and enhances lead oxide nanomaterials' antibacterial properties. The research is focused on focusing on environmental pollution control and treatment of different diseases such as asthma, bronchitis, tuberculosis, and other diseases through applications of Ayurveda, Siddha, Homeopathy, and Unani. A study based on these findings revealed that Adhatoda vesica (Justicia adhatoda) leaves extract can be utilized as a cost-effective and environmentally friendly alternative to producing lead oxide nanoparticles.