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This study delves into the impact of lithium (Li3+) and silver (Ag7+) ion irradiation on the structure and luminescence of Dy3+ doped and Dy3+/Eu3+ co-doped Gd2MoO6 phosphors, synthesized via the hydrothermal method. To explore the influence of ions with varied mass and energy, 30 MeV Li3+ and 100 MeV Ag7+ ions were employed at different fluences. We elucidate the induced effects based on defect formation and the role of these ions' linear energy transfer (LET) within the irradiated material. SRIM software estimates the depth profile of the ions. Irradiation of the Gd2MoO6 phosphors with Li3+ and Ag7+ ions resulted in the formation of disordered lattices or tracks, modifying their structural, optical, and luminescence properties, which were analyzed by various techniques, including X-ray diffraction, scanning electron microscopy, diffuse reflectance, and photoluminescence. Thermoluminescence (TL) tests and calculations of trapping parameters were conducted to evaluate the dosimetric potential. The findings reveal a more pronounced effect of silver ions compared to lithium ions on the structural and luminescence behavior of doped and codoped Gd2MoO6 phosphors due to their higher atomic weight. [ABSTRACT FROM AUTHOR]

Latent fingerprints (LFPs) are one among the most important types of evidences at crime scenes because of the distinctiveness and tenacity of the friction ridges in fingerprints (FPs). Therefore, it is essential in forensic science to develop a reliable method to detect LFPs. Traditional detection methods still face a number of difficulties, such as limited sensitivity, low contrast, strong background, and complex processing stages. In this study, MgO‐ZrO2:Tb3+ (1–5 mol%) (MZ:Tb) nanocomposites (NCs) were prepared via a simple solution combustion (SC) method at low temperature. The photoluminescence (PL) investigation demonstrates that when excited at 379 nm, the produced NCs emits distinctive emission peaks of terbium ions (Tb3+). According to the photometric results, the NCs can be employed as warm light NCs and emit light in the green portion of the colour spectrum. The estimated optical band gap from diffuse reflectance spectra is found to be in the range 4.84–4.97 eV. Regardless of the type of surface being used, the optimized MgO‐ZrO2:Tb3+ (4 mol%) (MZ:4Tb) NCs has a strong ability to minimize background fluorescence interference. With high contrast LFP and I–V type of cheiloscopy, these NCs present a flexible fluorescent mark for the identification of levels 1–3 details in forensic investigation. [ABSTRACT FROM AUTHOR]

Engineering a single material with multidirectional applications is crucial for improving productivity, low cost, flexibility, least power consumption, etc. To achieve these requirements, novel design structures and high-performance materials are in urgent need. Lanthanide-doped nanophosphors have the greatest strengths and ability in order to tune their applications in various dimensions. However, applications of nanophosphor in latent fingerprints visualization, anti-counterfeiting, and luminescent gels/films are still in their infancy. This study demonstrated a simple strategy to enhance the luminescence of Tb3+ (1–11 mol %) doped La2Zr2O7 nanophosphors by conjugating various fluxes via a simple solution combustion route. The photoluminescence emission spectra reveal intense peaks at ~ 491, 546, 587, and 622 nm, which arises from 5D4 → 7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions, respectively. The highest emission intensity was achieved in the NH4Cl flux assisted nanophosphor as compared to NaBr and NH4F assisted samples. The colorimetric images of fingerprints visualized using the optimized nanophosphor on forensic related surfaces exhibit level –III ridge details, including sweat pores, the width of the ridges, bifurcation angle, and the successive distance between sweat pores, etc. These results are decisive parameters that clearly support the statement "no two persons have ever been found to have the same fingerprints". The anti-counterfeiting security ink was formulated using optimized nanophosphor and various patterns were designed by simple screen printing and dip pen technologies. The encoded information was decrypted only under ultraviolet 254 nm light. All the designed patterns are exhibit not just what it looks/feel like and how better it works. As a synergetic contribution of enhanced luminescence of the prepared nanophosphor, the green-emissive films were fabricated, which display excellent flexibility, uniformity, and transparency in the normal and ultraviolet 254 nm light illumination. The aforementioned results revealed that the prepared NH4Cl flux-assisted La2Zr2O7: Tb3+(7 mol %) NPs are considered to be the best candidate for multi-dimensional applications. [ABSTRACT FROM AUTHOR]

The RGO-Y2O3 and RGO-Y2O3: Cr3+ (5 mol %) nanocomposite (NC) synthesized by hydrothermal technique. The structure and morphology of the synthesized NCs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Y2O3:Cr3+ displays spherical-shaped particles. Conversely, the surface of the RGO displays a wrinkly texture connecting with the existence of flexible and ultrathin graphene sheets. The photoluminescence (PL) emission spectra showed series of sharp peaks at 490, 591, and 687 nm which corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, and 4F9/2 → 6H11/2 transitions and lies in the blue, orange, and red region. The prepared NCs were used for the preparation of modified carbon paste electrodes (MCPE) in the electrochemical detection of dopamine (DA) at pH 7.4. Both modified electrodes provide a good current response towards voltammetric detection of DA. Doping is an effective method to improve the conductivity of Y2O3:Cr3+ and developed a method for the sensor used in analytical applications. [ABSTRACT FROM AUTHOR]

Novel Bi2Zr2O7:Sm3+ (1–9 mol%) nanoparticles (NPs) were synthesized via sonochemical method using Cetyltrimethylammonium bromide (CTAB) as a surfactant. The effects of primary synthesis conditions (pH, growth time, surfactant and dopant concentration) on the surface morphology have been reported for the first time. Photoluminescence (PL) studies (λex = 465 nm), CIE and CCT values revealed that the present nanophosphor could meet the needs of illumination devices and also for domestic appliances. Thermoluminescence studies show a well-resolved glow peak observed at ~ 182 °C along with a shoulder peak at ~ 116 °C be a good candidate for radiation dosimetric applications. This gamma dosimeter can be applied in the routine TL Dosimetry badge system among the gamma radiation workers involved in nuclear fuel cycle operations. Photocatalytic performance of at 5 mol% was experimented in the decolorization of Methylene Blue (MB) under natural Sunlight irradiation. [ABSTRACT FROM AUTHOR]

In Forensic investigation, identification of various types of ridge details are essential in order to fix the criminals associated in various crimes. Even though several methods and labeling agents are available to visualize latent finger prints (LFPs) there is still simple, accurate, cost-effective, and non-destructive tool is required. In the present work, CeO nanopowders (NPs) are prepared via simple solution combustion route using Tamarindus indica fruit extract as a fuel. The optimized NPs are utilized for visualization of LFPs on various surfaces by powder dusting method. Results revealed that visualized LFPs exhibit Level 3 features such as pores and ridge contours under normal light with high sensitivity and without background hindrance. The photometric characteristics of the prepared samples exhibit blue color emission and highly useful in warm light emitting diodes. The photocatalytic studies were carried out with different Methylene blue (MB) dye concentration and pH values. The obtained results reveal that the CeO NPs exhibits an excellent catalytic properties which can act as a good catalytic reagent. The findings demonstrate that the prepared NPs are quite useful as a labeling agent for visualization of LFPs, efficient catalysts for dye degradation as well as solid-state lighting applications. [ABSTRACT FROM AUTHOR]

Y2SiO5:Pr3+(1–9 mol%) nanophosphors were prepared via combustion synthesis usingCalotropis giganteaplant latex as fuel. The PXRD patterns of the sample revealed a monoclinic phase with phase group P21/Cn.14. The crystallite size was found to be in the range of 40–48 nm. The effect of Pr3+cations on the luminescence characteristics of YSO nanoparticles was studied. The CIE chromaticity coordinates were located in the yellow region. Hence, the present phosphor finds applications in light-emitting diodes and display devices. [ABSTRACT FROM PUBLISHER]

In this work, the influence of oxygen partial pressure on structural, morphological, and optical properties of TiO2 thin films grown on fused quartz substrate at different oxygen partial pressure by pulsed laser deposition were examined. X-Ray diffraction (XRD) patterns show the formation of TiO2 anatase phase deposited at high oxygen pressure. Atomic Force Microscopy (AFM) reveals that surface roughness of the films increases with oxygen pressure. Variation of surface morphology of films with increasing oxygen partial pressure was studied by AFM. It is observed that energy band gap of the films increases from 3.27 eV to 3.52 eV with the increase of oxygen pressure and is attributed to the decrease of oxygen defects. TiO2 thin films exhibited blue emission under the excitation of 320 nm wavelength. De-convoluted photoluminescence (PL) peaks showed that defect states are responsible for visible emission in TiO2 thin films. The intensity of PL emission associated with oxygen vacancies decreases with increasing oxygen pressure. Photometric characteristic analysis shows that the films deposited 1x10-4 mbar oxygen pressure exhibited intense blue emission with high luminescence efficacy of radiation. [ABSTRACT FROM AUTHOR]

A novel color tunable dye encapsulated mesoporous SiO/SrAlO:Eu,Dy composite long lasting phosphor (LLP) is developed. The color tuning was obtained by mixing the SrAlO:Eu,Dy (SAO) phosphor with rhodamine-B encapsulated mesoporous silica nanoparticles (MSNp-RhB) with an appropriate ratio. The photoluminescence emission spectra, phosphorescence spectra, photometric and phosphorescence decay measurement were utilized to characterize the composite phosphor. The composite LLP can be excited by UV lamp and also visible light due to broad excitation spectrum of SAO. A near white light emission was achieved with color co-ordinates (0.34, 0.39) and color temperature 5267 K. The detailed process is described here. The nature of phosphorescence decay of the composite LLP did not change with time which ensures constant and steady color during the decay process. The results indicate that the composite LLP can be potentially applicable as a new long lasting phosphor used in the field of emergency light, display, luminous paint and light emitting diode applications. [ABSTRACT FROM AUTHOR]

As-grown and chemically reduced Rh-doped (1500 p.p.m.) KnbO3 single crystals grown by the Czochralski method have been characterized. Reduction of the grown crystals at different levels was carried out under a mixture of CO and CO2 gases as the crystals were grown with excess oxygen. The effect of reduction and poling on crystalline perfection was studied by high-resolution X-ray diffraction (HRXRD) using a multi-crystal X-ray diffractometer developed in-house. The diffraction curves of the as-grown, electrically poled, moderately reduced and heavily reduced single-crystal specimens show remarkable differences. The studies by HRXRD reveal that poling has some influence on the improvement of crystalline perfection, while chemical reduction has a great influence on crystalline perfection; at moderate reduction the crystal becomes nearly perfect, but when the reduction is very heavy the crystal quality decreases slightly, although it is still better than for unreduced samples. Asymmetry of the diffraction curves with respect to the peak position reveals that the as-grown specimens contain a high concentration of both vacancies and self-interstitials. After poling, the concentration of self-interstitial defects is lowered to some extent. When the specimen is moderately chemically reduced, the scattered intensity on both sides of the peak is greatly reduced, showing that the concentrations of both vacancies and interstitials are reduced to a great extent owing to chemical reduction. This clearly indicates that, as a result of the chemical reduction of oxygen in the crystal, crystalline perfection is enhanced significantly. However, under heavy chemical reduction, the number of vacancy defects is increased to a significant extent. Raman scattering, dielectric and photoluminescence studies also show interesting features, with excellent correlation with the degree of crystalline perfection influenced by the processes of reduction and poling. [ABSTRACT FROM AUTHOR]

An array of Eu3+ doped Ba 2 GdSbO 6 luminescent materials have been synthesized by the conventional solid-state (high temperature) reaction route. Surface morphology has been studied via Field Emission Scanning Electron Microscopy. The structural and optical behaviors have been studied using X-Ray Diffraction (XRD), FTIR, Raman spectroscopy, Diffuse reflectance spectroscopy, Photoluminescence excitation (PLE), and Photoluminescence emission (PL) spectra. FTIR and Raman's spectra provided the chemical functional group and different vibrational levels within the samples. The calculated optical band gap was 4.40 eV and 4.47eV for pure and optimized samples respectively. Photoluminescence emission curves have been recorded for 245 nm of excitation wavelength and the highest emission peak was focused at 595 nm corresponding to 5D 0 → 7F 1. Similarly, the Photoluminescence excitation curves were monitored at the emission wavelength of 595 nm and a broad charge transfer band (CTB) was observed from 230 to 285 nm. The emission spectra show the concentration quenching effect beyond the 2 mol% Eu3+ concentration. The corresponding transitions of Eu3+ were further utilized to obtain the Judd-Ofelt (J-O) transition intensity parameters Ω λ (λ = 2, 4) for each sample. Additionally, by studying decay kinetics, the average lifetime of the red emission of the samples has been evaluated, which was 4.622 ms. The photometric study also reveals the CIE coordinates, color purity and CCT values of the proposed phosphor material. Thus, the results obtained from these characterizations, suggest that the prepared sample may behave as a potential candidate in the case of UV-excited red light-emitting phosphor material for light-emitting diodes and field emission devices. • Ba 2 GdSbO 6 : Eu3+ phosphors have been synthesized by solid-state reaction method. • Rietveld refinement has been carried out for better crystal structure analysis. • Raman studies for this host Ba 2 GdSbO 6 have been carried out for the first time. • The phosphors show intense photoluminescence emission with very high color purity. • Judd-Ofelt analysis has been done to understand the spectroscopic behavior of the proposed phosphor material. [ABSTRACT FROM AUTHOR]

Despite extensive efforts to design a white light generating phosphor, single component phosphors which exhibit multi-color emissions are very limited. In this work we report the synthesis of novel single component colortunable strontium cerate (Sr2-xSmxCeO4) phosphor using facile low temperature solution combustion synthesis. A single-composition, color tunable phosphor is produced by doping with different concentrations of Sm3+ (0.0 to 0.11) into the Sr2CeO4 matrix. Chromaticity of Sr2-xSmxCeO4 depends on the Sm3+ concentration. This is because of energy transfer from Sr2CeO4 to Sm3+ determines the emission colors of the phosphors. At low concentration of Sm3+, Commission Internationale d'Eclairage (CIE) coordinates that are very close to white light emission (0.317, 0.303) are observed. However, at higher dopant concentration (x = 0.11 of Sm3+) the compound exhibits red emission (0.407, 0.343). Hence, a single host multi-color emitting phosphor is realized by doping and energy transfer. Thermoluminescence studies are carried out for Sr2CeO4:Sm3+ phosphor using γ-irradiation in the dose range of 0.5 to 5 kGy. The kinetic parameters, namely activation energy (E), frequency factor (s) and order of kinetics (b) were estimated by Chen's glow peak shape method and are discussed in detail for their possible usage in dosimetry. [ABSTRACT FROM AUTHOR]

Intrinsic defect generated photoluminescence (PL) in zinc oxide nanoparticles (NPs) obtained by a PVA template based wet-chemical process has been studied. A good controllability was achieved on the surface defects, structure and the morphology of ZnO NPs through the variation of solvents used in synthesis. The PL emission strongly depended on the defect structure and morphology. SEM, XRD, annealing and PL excitation studies were used to analyze the types of defects involved in the visible emission as well as the defect concentration. The mechanism for the blue, green and yellow emissions was proposed. The spectral content of the visible emission was controlled through generation/removal of defects through the shape transformation or annealing by focusing on defect origins and broad controls. [ABSTRACT FROM AUTHOR]

FeMoO 4 nanorods and their rare earth (Eu 3+ and Tb 3+ ) doped composites with nitrogen doped graphene (NG) were synthesized by facile hydrothermal method in aqueous medium. X-ray diffraction (XRD) analysis of the as-synthesized samples was done to study the phase purity and crystalline nature. FTIR and Raman Spectroscopy have been studied for investigating the bonding in nanostructures. The surface morphology of the samples was investigated with field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The photolumniscent nature of the samples was investigated by the using the fluorescence spectrophotometer. The photocatalytic degradation efficiency of the prepared pure FeMoO 4 and its rare earth doped composites with nitrogen doped graphene was evaluated as function of visible light irradiation versus concentration of methylene blue (MB dye). The prepared nanocomposites show enhanced photocatalytic efficiency as compared to the bare FeMoO 4 nanorods. [ABSTRACT FROM AUTHOR]

In the present work, we have developed a novel, ecofriendly method for the synthesis of ZnO superstructures for the first time through the thermal decomposition of zinc nitrate precursor without using any fuel. The synthesized materials were thoroughly characterized using various analytical tools such as X-ray diffraction, Fourier-transform infrared spectrometry, UV-vis, scanning electron microscopy, and transmission electron microscopy. Further, it has been used as a photocatalyst for the degradation of one of the environmental pollutants such as methylene blue and also as a biosensor toward the detection of dopamine at trace level. The as-synthesized ZnO nanoparticles showed superior catalytic activity toward the degradation of methylene blue dye with high degree of recyclability with yellow light emitting photoluminescence. The developed sensor showed a linear range for dopamine up to 300 μM with a detection limit of 1 μM with reproduced results over periods of several months without any deviation in its electrochemical performance. [ABSTRACT FROM AUTHOR]

GdAlO3, GdAlO3:Eu3+ and GdAlO3:Eu3+:Bi3+ nanophosphors were synthesised by solution combustion technique. Pure orthorhombic phase was obtained from powder X-ray diffraction (PXRD) studies. Scanning electron microscopy (SEM) micrographs showed the porous, agglomerated and irregular shaped particles. The particle size obtained by transmission electron microscopy (TEM) measurement was in good agreement with the values obtained by Debye Scherrer's and W-H plots. The selected area electron diffraction (SAED) pattern show single crystalline nature of the sample. Photoluminescence (PL) measurements were carried out for GdAlO3:Eu3+ and GdAlO3:Eu3+:Bi3+ phosphors excited at a wavelength of 274nm. The characteristic emission peaks of Eu3+ ions were recorded at 590, 614, 655 and 695nm corresponding to 5D0→7FJ (J=1, 2, 3, 4) transitions respectively. However, with addition of Bi3+ ions in GdAlO3:Eu3+, PL intensity drastically enhanced. Orange red color was tuned to deep red color with the addition of Bi3+ ions in GdAlO3:Eu3+ phosphor. Therefore, the phosphor was highly useful as red component in WLEDs. A single well resoled glow peak at 225°C was recorded in GdAlO3 and GdAlO3:Eu3+. Further, with addition of Bi3+ ions, an additional peak at 300°C was recorded. TL glow curves of different UV-exposed GdAlO3:Eu3+:Bi3+ show two TL peaks at 207 and 300°C respectively. The 207°C peak show simple glow peak structure and its intensity increases linearly up to 25min and after that it decrease. [ABSTRACT FROM AUTHOR]

The investigation involves preparation and photoluminescence properties of CeO2:Eu3+ (1-11mol%) nano phosphors by eco-friendly green combustion route using Euphorbia tirucalli plant latex as fuel. The final product was characterized by powder X-ray diffraction (PXRD), Scanning electron microcopy (SEM) and Transmission electron microscopy (TEM). The PXRD and SEM results reveals cubic fluorite phase with flaky structure. The crystallite size obtained from TEM was found to be ~20-25nm, which was comparable to W-H plots and Scherrer's method. Photoluminescence (PL) emission of all the Eu3+ doped samples shows characteristic bands arising from the transitions of 5D0→5FJ (J=0, 1, 2, 3, 4) manifolds under excitation at 373 and 467nm excitation. The 5D0→7F2 (613nm) transition often dominate the emission spectra, indicating that the Eu3+ cations occupy a site without inversion center. The highest PL intensity was recorded for 9mol% Eu3+ ions with 5ml latex. PL quenching was observed upon further increase in Eu3+ concentration. The international commission on illumination (CIE) chromaticity co-ordinates were calculated from emission spectra, the values (x, y) were very close to national television system committee (NTSC) standard values of pure red emission. The results demonstrate that the synthesized phosphor material could be very useful for display applications. Further, the phosphor material prepared by this method was found to be non toxic, environmental friendly and could be a potential alternative to economical routes. [ABSTRACT FROM AUTHOR]