Luminescence最新文献

In this study, we employ spectroscopic, thermodynamic and molecular docking approaches to identify the mechanism by which thiazolidinone derivatives 4a–4d bind with human serum albumin. It has been suggested that the affinity of the interaction of derivatives 4a–4d with HSA is within the optimal range necessary for the transportation and distribution of compounds within the organism. The binding constant values for the derivative/HSA complexes were found to be 0.03–5.87 × 10⁵ M⁻¹. Both ΔH⁰ and ΔS⁰ values were negative, which indicates that binding occurs mainly through van der Waals forces and hydrogen bonding. The negative values calculated for ΔG⁰ indicate that the binding of derivatives 4a–4d with HSA is a spontaneous process. Our study also reveals that derivatives 4a–4d bind to the subdomain IB (Site III) of HSA and that this binding alters the conformation and thermodynamic stability of HSA. Molecular docking simulations suggest that the main binding forces are van der Waals interactions, hydrophobic interactions and hydrogen bonds. The studied compounds showed weak DPPH-scavenging activity at all of the tested concentrations. The results suggest that compound 4b with a phenyl substituent at the nitrogen atom of the 1,3-thiazolidin-4-one moiety can be considered the most potent antioxidant in the series.

Spherical-shaped nickel cobaltite (NC) nanoparticles were synthesized via a simple sol–gel technique and calcined at 600°C. X-ray diffraction (XRD) analysis revealed significant changes in crystallite size, with an average of 23 nm for the control sample and variations observed after 50 shockwaves. Fourier transform infrared spectroscopy (FTIR) confirmed metal-oxygen stretching, indicating structural integrity. UV–visible absorption studies showed changes in the optical band gap, which increased after shock treatments, suggesting bandgap tunability for optoelectronic and photovoltaic applications. The material exhibited good optical absorption up to 600 nm, making it suitable for light-harvesting devices. Vibrating sample magnetometry (VSM) detected shifts in dipole moments and magnetic saturation, with all samples displaying paramagnetic behavior. The shock-treated samples showed enhanced magnetic properties, which could be useful in magnetic storage devices. The combined tunability of bandgap and magnetic properties via shock wave treatment underscores the potential of these nanoparticles for applications in photovoltaics, spintronics, and energy storage systems.

A series of green phosphors, Ca_1-y%MoO₄:y%Tb³⁺ (where y = 0.1, 0.5, 1, 2, 3, 4, and 5) were successfully prepared via hydrothermal synthesis. The pH levels were used to modulate the luminescent of CMO:Tb. To confirm the potential application of proposed phosphors, Blueberry anthocyanin (BBA) was loading onto CMO:Tb surface to form a luminescence probe. The synthesized phosphors and probes were characterized using X-ray diffraction (XRD), FT-IR spectra, transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). As a proof-of-concept, the constructed probes were adopted to evaluate the acidity of solution. The results showed that luminescence emission intensity at 546 nm increased with pH value increasing in the range of 2–12. Meanwhile, the color of the sensor solution changed from bright red to pink, then to purple, and finally to yellow as the pH varies between 2 and 12. The above results indicated that the proposed probe could evaluate the acidity of solution via the dual-mode luminescence detecting and naked eye to obtain accurate results. This proposed strategy gives an insight to design the efficient probes to precisely and sensitively evaluate the acidity in complex samples.

In this work, a facile and rapid fluorescence turn-off-on sensing method was developed for the detection of Pb²⁺ and metalaxyl fungicide in environmental samples using yellow carbon dots (CDs) from Cordia dichotoma fruits. The prepared C. dichotoma-CDs showed the emission band (𝜆_Em) at 535 nm under 448 nm of excitation wavelength. The fluorescence intensity of C. dichotoma-CDs quenches by Pb²⁺ ion and then restores by metalaxyl fungicide, favoring to develop a fluorescence turn-off-on sensing strategy. The intensity ratios (I₀/I and I/I₀) are linear against Pb²⁺ (0.01–50 μM) and metalaxyl fungicide (0.025–10 μM) concentrations, offering the detection limits of 0.0054 and 0.0087 μM for Pb²⁺ and metalaxyl fungicide, respectively. Additionally, the potential application of C. dichotoma-CD-based fluorescence turn-off-on sensing approach was effectively demonstrated for Pb²⁺ and metalaxyl fungicide assays in real samples, which confirms that C. dichotoma-CDs act as “turn-off-on” fluorescent probe for assaying of Pb²⁺ and metalaxyl fungicide, respectively.

BaSO₄:V⁵⁺ synthesized at 1000°C in air exhibits an intense emission band peaking at 495 nm from surface traps assisted by atmospheric oxygen on excitation at 350 nm due to charge transfer from O²⁻ to V⁵⁺ in the (VO₄)³⁻ tetrahedral complex. BaSO₄:Eu synthesized under similar conditions exhibits both Eu²⁺ (375 nm) and Eu³⁺ (619 nm) fluorescence. Vanadium codoping quenches the Eu²⁺ fluorescence but enhances the Eu³⁺ fluorescence in BaSO₄:V, Eu due to charge compensation. However, Eu codoping quenches the vanadium fluorescence by diffusion of vanadium into the crystal, and V₂O₅ also serves as a flux enhancing Eu³⁺ doping efficiency in BaSO₄ lattice. The 619nm Eu³⁺ PL emission intensity in BaSO₄:V⁵⁺, Eu³⁺ is comparable to 592nm emission from commercial (Y,Gd) BO₃:Eu³⁺. However, V⁵⁺ emission shows strong thermal quenching, while Eu³⁺ emission shows little thermal quenching up to 210°C, making BaSO₄:V⁵⁺, Eu³⁺ a promising new red phosphor for improving the color rendering of blue light-based white LED. The ratio of Eu³⁺ to V⁵⁺ fluorescence increases with excitation temperature (30°C°C–180°C) enabling BaSO₄:V⁵⁺, Eu³⁺ to be used as a non-contact luminescence thermometer.

A rapid and highly sensitive first derivative synchronous fluorescence spectrometry with double scans was successfully optimized for the simultaneous determination of dissolved phenanthrene (Phe), 1-methylphenanthrene (1-MP), and 3-methylphenanthrene (3-MP) and their metabolites such as 1-hydroxy-2-naphthoic acid (1H2NA) and salicylic acid (SA) in the biodegradation processes of Phe, 1-MP, and 3-MP by Novosphingobium pentaromativorans US6-1. Δλ of 55 and 109 nm were selected for Phe, 1-MP, 3-MP, 1H2NA, and SA, respectively. The intensities of the first derivative synchronous fluorescence detected at λex of 289, 292, 291, 354, and 312 nm for Phe, 1-MP, 3-MP, 1H2NA, and SA varied linearly with the concentrations of them in the ranges of 0.20 × 10⁻⁷–44.89 × 10⁻⁷, 0.20 × 10⁻⁷–13.04 × 10⁻⁷, 0.20 × 10⁻⁷–13.04 × 10⁻⁷, 0.22 × 10⁻⁷–76.30 × 10⁻⁷, and 0.11 × 10⁻⁷–52.00 × 10⁻⁷ mol/L. The limits of detection were 0.11 × 10⁻⁹, 0.30 × 10⁻⁹, 0.27 × 10⁻⁹, 0.33 × 10⁻⁹, and 2.90 × 10⁻⁹ mol/L for Phe, 1-MP, 3-MP, 1H2NA, and SA, respectively, with RSD less than 2%. The method was successfully applied in situ to detect the instantaneous concentrations of the PAHs and their metabolites, especially SA, during their biodegradation processes under simulated conditions in the lab. The results demonstrated that the upper metabolic pathways of 1-MP and 3-MP by US6-1 were distinctly different from that of Phe owing to steric hindrance of the methyl group.

Er³⁺ and Er³⁺/Yb³⁺-doped phosphate-based glasses have been synthesized by melt quenching technique and are characterized by absorption spectra, infrared emission, decay curves, Fourier transform infrared spectrum and up-conversion studies. From the absorption spectra, intensity parameters and radiative properties have been derived utilizing the Judd–Ofelt theory. Er³⁺-doped glass is found to have larger radiative lifetime for the laser originating from ⁴I_13/2 level at 1537 nm. Infrared and visible characteristic emissions have been measured by exciting at 790 nm through down- and up-conversion, respectively. The up-conversion spectra consist of intense green emission at around 525 and 545 nm ascribed to the ²H_11/2 → ⁴I_15/2 and ⁴S_3/2 → ⁴I_15/2 transitions, respectively, and a weak red emission at around 656 nm due to the ⁴F_9/2 → ⁴I_15/2 transition of Er³⁺ ions. Various spectroscopic and laser characteristics of these glasses have been calculated and compared with those of similar reported ones.

The present study focused on extracting the anthocyanin dyes in ethanol, acidic ethanol, methanol, and acidic methanol solvents from Nerium oleander flowers by a simple maceration extraction process. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.89 eV), indirect bandgap (1.98 eV), Urbach energy (0.120 eV), high refractive index (1.654), dielectric constant (3.294) and high optical conductivity (1.813 10³ S/m) for the anthocyanin dye extracted found in acidic ethanol solvent. The photoluminescence properties such as Stokes' shift, quantum yield, and lifetime results show that anthocyanin dyes are promising candidates for red-LEDs and optical materials. The excellent correspondence between the absorption and emission spectra reinforces that the anthocyanins are efficient (89%) FRET probes. Further, the donor and acceptor undergo redshift in excitation and emission spectra in all studied solvents. The photometric properties such as CIE, CRI, CCT and color purity results of anthocyanins in all studied solvents revealed that this material exhibits pink to red shades (x = 0.40 → 0.50 and y = 0.46 → 0.39) and is well suitable for have great potential in the manufacturing of Organic-LEDs and other optoelectronic device applications.