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This study presents the synthesis of orange–red emitting Sr9Al6O18:Pr3+ nanophosphors (SAO:Pr3+ NPs) through the solution combustion process. Photoluminescence (PL) spectra revealed concentration quenching at 5 mol % with a critical distance of RC = 21.5 Å, indicating that electric multipolar interactions are responsible for the nonradiative energy transfer in the SAO lattice. Dexter's theory confirmed the quadruple–quadruple interaction as the mechanism behind the quenching. The optimized SAO:5Pr3+ NPs exhibited exceptional properties, including high color purity (CP = 94.2%), cost-effectiveness, eco-friendliness, scalability, and photostability. A fluorescence-based technique was developed using powder dusting to apply latent fingerprint (LFP) visualization and preservation. This method demonstrated high sensitivity, contrast, and no background interference, enabling the detection of LFPs over extended periods. Furthermore, lip prints (LPs), known for their sex differences and stability, have been effectively utilized for reliable and efficient forensic investigations. An unclonable invisible security ink was developed to combat counterfeiting, exhibiting high stability against UV light, aging, and physical abrasion. Mathematical models were employed for various fingerprint image processing tasks, including segmentation, normalization, ridge orientation estimation, ridge frequency estimation, Gabor filtering, binarization, thinning, and minutiae extraction. These algorithms were implemented by using a Python-based environment, resulting in enhanced fingerprints that displayed level I–II features. These findings underscore the potential applications of SAO:Pr3+ NPs in advanced forensic science and data security. This study offers insights into the synthesis, characterization, and application of SAO:Pr3+ NPs, highlighting their suitability for advanced forensic investigations, data security, and anticounterfeiting measures. [ABSTRACT FROM AUTHOR]

Using the co-precipitate method, Mg-doped CoCr2O4 nanoparticles (NPs) with a particle size ranging from 11 to 22 nm were synthesized, and their structural, surface, vibrational, and magnetic properties were examined through experimental and theoretical approaches. The inherent magnetic inhomogeneity of the NPs was found to be the cause of the observed exchange bias effect. The magnetic memory effect was studied below the spin glass-transition temperature using time- and temperature-dependent magnetization measurements, and the magnetocaloric effect was investigated across the Curie temperature. These NPs show promising potential for magnetic memory and magnetocaloric effect fields. [ABSTRACT FROM AUTHOR]

The cadmium tungstate rods have been given much attention due to their potential for usage in numerous luminescent applications. We have prepared single crystalline Sn-doped Cd1−xSnxWO4 (where x = 0, 1, 3, and 5%) nanorods (NRDs) and characterized them using refined X-ray diffraction and TEM analysis, revealing a monoclinic phase and a crystallite size that decreased from 62 to 38 nm as Sn concentration increased. Precise Sn doping modulation in CdWO4 NRDs causes surface recombination of electrons and holes, which causes the PL intensity to decrease as the Sn content rises. The chromaticity diagram shows that an increase in the Sn content caused a change in the emission color from sky blue to light green, which was attributed to the increased defect density. The photoluminescence time decay curve of all samples fit well with double-order exponential decay, and the average decay lifetime was found to be 1.11, 0.93, and 1.16 ns for Cd1−xSnxWO4, x = 0, 1, and 5%, respectively. This work provides an understanding of the behavior of Sn-doped CdWO4 NRDs during electron transitions and the physical nature of emission that could be used in bio-imaging, light sources, displays, and other applications. [ABSTRACT FROM AUTHOR]

Monoclinic CdWO4 is a member of the tungstate family with great potential in diverse applications. However, CdWO4 exhibits a diamagnetic property with a wideband gap of 3.7 eV, limiting its widespread applications. This study reports significant modulation of magnetic and optical properties of hydrothermally grown single-crystalline CdWO4 nanorods with controllable substitution of Cu2+ ions at the Cd2+ site. The chemical environment of Cu and the magnetic and luminescence of nanorods were thoroughly investigated using synchrotron-based powder X-ray diffraction, temperature-dependent photoluminescence, X-ray absorption, element selective X-ray excited optical luminescence spectroscopies, a magnetometer, and micro-Raman spectroscopy. The main feature of this study is an astonishing redshift of ∼0.8 eV in the bandgap energy accompanied by a relative ∼46% drop in the internal quantum efficiency and a progressive transition from diamagnetic to an enhanced magnetization concerning the Cu content. The experimental findings show that significant modulation in optical and magnetic properties is correlated with Cu-doping-induced intermediate energy states and [CuO6] ferromagnetic clusters. The outcome of this study provides important insight into designing doped nanomaterials for photocatalytic applications. [ABSTRACT FROM AUTHOR]