Luminescence最新文献

Imidacloprid (IMI) is an insecticide used worldwide, and its toxicity raises concerns for nontarget organisms. A photoinduced (PI) flow injection technique is employed for the estimation of IMI with diperiodatocuperate (III) (DPC)–H₂SO₄ chemiluminescence (CL) reaction. The analysis was based on the IMI irradiation with ultraviolet light, which results in the generation of a fluorophore product and gets excited by the energy from the CL reaction. The effects of physical and chemical parameters such as reagent concentrations, voltage of the photomultiplier tube, length of the photo reactor coil, volume of samples, and flow rate were optimized. Solid phase extraction (SPE) and liquid extraction were employed as phase separation techniques. The calibration curve was linear in the range of 0.0001–20 mg/L for IMI with the equation of regression: y = 527.44x + 0.0182 (R² = 0.9999; n = 14) and RSD (n = 3) 1.5%–2.8% over the range studied. Recoveries were in the range of 95%–101% for commercial samples and 96–110% for water samples. The limit of detection (S/N = 3) was 5 × 10⁻⁵ mg/L and the method achieved an injection throughput of 80 h⁻¹. The method can estimate IMI in fresh water samples and commercial formulations. Possible CL reaction was also studied.

A series of K₅La_1 − x (MoO₄)₄:xTm³⁺ and K₅La_{0.95 − y} (MoO₄)₄:0.05Tm³⁺,yDy³⁺ phosphors have been synthesized via high-temperature solid-state reaction at 600°C for 8 h, and then their luminescence property and thermal stability were investigated. It was found that the K₅La_1 − x (MoO₄)₄:xTm³⁺ phosphors exhibited two strong blue emission peaks at 452 and 458 nm under excitation at 356 nm with the strongest intensity in the case of x = 0.05, whereas the K₅La_{0.95 − y} (MoO₄)₄:0.05Tm³⁺,yDy³⁺ phosphors exhibited another two characteristic peaks of Dy³⁺ at 479 and 574 nm, and Tm³⁺ could transfer energy to Dy³⁺. Notably, even at 473 K, the emission intensity of K₅La_0.95(MoO₄)₄:0.05Tm³⁺ and K₅La_0.875(MoO₄)₄:0.05Tm³⁺,0.075Dy³⁺ phosphors at 452 nm still kept 62.33% and 75.03% of those at room temperature, respectively, indicating a high thermal stability. Moreover, the emission spectra and color coordinates of the co-doped phosphors can be regulated via changing the excitation wavelength. Specifically, the color coordinates of K₅La_0.875(MoO₄)₄:0.05Tm³⁺,0.075Dy³⁺ was (0.3223, 0.3346) under excitation at 350 nm, very close to the standard white light, implying a potential in white light LED.

In this study, Eu (III) complex/CaCO₃ composite fluorescent materials were prepared by employing CaCO₃ as a substitute for conventional alkaline reagents. The composite materials were comprehensively characterized by means of FT-IR, XRD, TG-DTA, SEM, TEM, ICP, EDS, and fluorescence spectroscopy to investigate their structural and performance properties. The results demonstrated that a CaCO₃-core@shell structure was successfully constructed in the composite material. Through this structural configuration, the acid present in the reaction system was effectively neutralized by CaCO₃, while an environmentally benign preparation process was simultaneously achieved. The fluorescent properties of the composite material were systematically investigated. A maximum absolute quantum yield of 48.39% was measured, representing a 3.39% enhancement compared with the pristine Eu (TTA)₃Phen complex. Concurrently, the fluorescence lifetime in the composite material was stable at 0.78–0.80 ms due to reduced quenching from the dilution effect of CaCO₃. Furthermore, when the composite material was implemented in LED devices, warm-tone red emission was achieved with a fluorescent intensity of 21,970 cd/m² being attained. A novel strategy for preparing green and resource-efficient rare earth complexes was developed in this study. The composite material was demonstrated to possess potential applications in agricultural films, lighting, and display technologies.

An environmentally benign microwave-assisted method was developed to synthesize nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) from Cichorium intybus leaves, enabling their use as efficient fluorescent nanosensors. The method is incredibly quick, enabling the acquisition of N,S-CQDs in under 50 s. Their unique optical and structural characteristics were confirmed by thorough characterization using HR-TEM, EDX, zeta potential, FT-IR, UV–Vis, and fluorescence spectroscopy. The N,S-CQDs exhibited a quantum yield of 24%, highlighting their strong potential as fluorescent nanoprobes. Notably, they displayed switch-off fluorescence behavior suitable for the determination of the anticancer drug lapatinib in spiked human plasma and environmental water samples. The method demonstrated excellent linearity across 0.2–8.0 μg/mL (r > 0.999) with a detection limit of 0.05 μg/mL. High recovery values in plasma and water matrices further validated the sensitivity and accuracy of the approach. Moreover, sustainability and performance were systematically evaluated using the Analytical Green Star Area (AGSA) and the Multi-color Assessment platform for White Analytical Chemistry (MA-tool), confirming the technique's environmental friendliness, broad applicability, analytical robustness, and novelty. This pioneering work paves the way for the development of green nanoprobes with significant relevance in biological and environmental monitoring.

This study presents the synthesis and characterization of novel reduced carbon dots (rCDs) through a facile and efficient method. The resulting rCDs are characterized by various analytical and spectroscopic techniques. The rCDs exhibit strong chemiluminescence (CL) in the presence of luminol, representing a significant advancement in analytical applications. Leveraging this enhanced CL, a sensitive and selective method was developed for determining sulfite residues in dried apricot samples. Reverse flow injection analysis (rFIA) was employed for the measurements, offering rapid response and high throughput. The method achieved a detection limit of 0.001 mg/L, with a linear calibration range of 0.01–5.0 mg/L and an error margin below 4.0%. Validation results confirmed the method's reliability, accuracy, and precision. Successful application to real dried apricot samples underscores its practical relevance. Overall, the findings highlight the potential of rCDs as CL probes in food safety analysis, contributing to public health and environmental monitoring by enabling the rapid detection of sulfite preservatives in food products.

Combining PI3K/mTOR inhibitor Pictilisib with green tea polyphenol EGCG holds promise in cancer therapy but may alter pharmacokinetics via human serum albumin (HSA) binding. This study elucidates their cooperative interactions with HSA under physiological conditions using multispectroscopy (steady-state fluorescence, UV–Vis, circular dichroism [CD], synchronous, and three-dimensional [3D] fluorescence), competitive binding assays, molecular docking, and molecular dynamics (MD) simulations. Fluorescence quenching revealed coadministration of Pictilisib and EGCG with HSA exhibits higher binding constants (up to 10⁶ M⁻¹) and stronger hydrophobic interactions compared to binary systems, driven by entropy-dominated static quenching. Structural characterization by CD, synchronous, and 3D fluorescence spectroscopy demonstrated that combined drug binding induces progressive α-helix reduction and conformational reorganization in HSA, which alters the microenvironment of Trp/Tyr residues. Molecular docking and site probes show Pictilisib displaces prebound EGCG from Sudlow Site I (IIA), whereas EGCG binds subdomain IB when Pictilisib occupies Site I first, highlighting administration-order dependency. One-hundred-nanosecond MD simulations confirm ternary complexes increase HSA's solvent accessibility (SASA), flexibility (RMSF), and structural expansion (Rg), particularly in Subdomains IIA and IIIA. These results demonstrate that HSA-mediated EGCG–Pictilisib interactions are sequence dependent, critically influencing drug distribution and bioavailability. This mechanistic insight provides a foundation for optimizing coadministration schedules in combinatorial cancer therapy.

In this work, the UVB emission of Gd³⁺ ions incorporated into the Na₂O–Ga₂O₃–B₂O₃–Y₂O₃ glass matrix was thoroughly investigated by varying the concentration of Gd₂O₃. Photoluminescence measurements revealed a strong and well-defined emission peak at 312 nm, related to the ⁶P_7/2 → ⁸S_7/2 transition of Gd³⁺ ions under 273 nm excitation. Notably, the emission intensity increased nearly threefold as the Gd₂O₃ concentration rose from 0.2 to 0.8 mol%. The results were examined using Judd–Ofelt analysis and supported by decay kinetics, infrared spectra, ESR spectra, and DSC studies. The enhancement of luminescence was mainly attributed to reduced phonon losses associated with Ga₂O₃. However, a decline in emission intensity at 1.0 mol% Gd₂O₃ was observed, which was ascribed to ion clustering and cross-relaxation processes. Overall, this study demonstrates that tailoring the Gd₂O₃ concentration provides an effective approach to enhance UVB output in alkali–yttria–gallium–borate glasses. The composition containing 0.8 mol% of Gd₂O₃ is identified as a promising luminescent material for phototherapeutic applications, particularly in the treatment of skin disorders such as psoriasis and vitiligo, and for use in the fabrication of phototherapy devices.

Carbon quantum dots (CQDs) are carbon-based semiconductor nanomaterials that have attracted significant attention due to their unique optical properties, biocompatibility, and environmentally friendly nature. These features make them promising candidates for the sensitive and selective detection of harmful pesticides, particularly chlorpyrifos (CP), a widely used organophosphate insecticide that poses environmental and health risks. In this study, CQDs were synthesized via a hydrothermal method using grape acid and three different amino acids (L-cysteine, L-tryptophan, and L-serine). They were comparatively evaluated based on the type of amino acid used. The amino acids enhanced the surface functionalities of the CQDs, which were confirmed by scanning transmission electron microscopy (STEM) and density functional theory (DFT) analyses, including the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) energy levels. The developed CQD based fluorescence sensor demonstrated high sensitivity and selectivity toward CP among four tested pesticides. Notably, cysteine-doped CQDs exhibited superior sensing performance at low concentrations (7.42 × 10⁻¹² mol L⁻¹). This study highlights the potential of amino acid–functionalized CQDs as effective, low-cost, and environmentally friendly platforms for the sensitive monitoring of pesticides, offering essential applications in environmental safety and public health protection.

To date, most luminescence studies on MOF-76 have focused on tetragonal Tb³⁺-doped and Tb³⁺/Eu³⁺ co-doped systems. In this work, MOF-76(Gd, Dy) and MOF-76(Gd, Tb, Dy, Eu) were synthesised for the first time and subsequently subjected to hydrothermal annealing in the presence of polyvinylpyrrolidone (PVP) as a dispersant. Annealing induced a tetragonal → monoclinic phase transition in MOF-76 and transformed the morphology from rods into highly crystalline, transparent nanosheets. As a result, the emission intensity of annealed MOF-76(Gd_0.98, Dy_0.02) increased by approximately 25-fold and its photoluminescence quantum yield (PLQY) improved from 2.33% to 18.60%. These enhancements enabled the combination of hydrothermal annealing with a lanthanide co-doping strategy to achieve precisely tunable, highly luminescent colours in the multi-doped MOF-76(Gd, Tb, Dy, Eu) system. In the annealed materials (aMOFs), efficient Tb³⁺ → Dy³⁺ and Dy³⁺ → Eu³⁺ energy transfer pathways were identified. Owing to their high luminescence and colour tunability, the resulting materials demonstrated practical applicability in colour-tunable fluorescent anti-counterfeiting and, when combined with N-CDs@starch, in white-light-emitting LED devices.

Thermal luminescence stability is a key challenge in developing luminescent materials for various applications. Photoluminescent properties of two red-emitting complexes, [Eu (PHT)₃·H₂O] and [Eu (PHT)₃], were studied. Infrared spectroscopy demonstrated characteristic ν_as (COO⁻) and ν_s (COO⁻) bands of coordinated carboxylates. Photoluminescence confirms an effective ligand to metal energy transfer in the [Eu (PHT)₃⸱H₂O] and [Eu (PHT)₃] complexes, resulting in the characteristic Eu³⁺ ion transitions corresponding to ⁵D₀ → ⁷F_J (J = 0–4). Luminescence lifetime (τ), Absolute Quantum Yield (Ф), and quantum efficiency (η) revealed an increase of nonradiative deactivation channels in the [Eu (PHT)₃⸱H₂O] complex due to the presence of O–H oscillators when compared to the [Eu (PHT)₃] complex. Photometric analysis placed both complexes in close agreement with NTSC red coordinates (x = 0.67, y = 0.33), and full color-purity values above 93%. The temperature-dependent luminescence of the [Eu (PHT)₃] complex exhibited thermal stability up to 423 K, maintaining a signal of 70%. In contrast, the initial intensity of the [Eu (PHT)₃·H₂O] complex increases up to 50% in the 393–413 K range, causing intensity variations and reduced reproducibility suggested by the presence of the water molecule. These results indicate that the anhydrous [Eu (PHT)₃] complex is an efficient red-emitting phosphor for optoelectronic devices.