Luminescence Response Research Articles

Optical temperature sensing properties realized by isotropic negative thermal expansion in ScF3:Tb3+/Eu3+ phosphor ceramics

The anomalous luminescence thermal quenching performance caused by negative thermal expansion has attracted much attention due to the potential application in optical fields. However, the downshifting emissions with abnormal thermal quenching achieved by isotropic negative thermal expansion for optical temperature sensing applications are still lacking. Herein, a large enhancement of red emission and a high temperature sensing performance are realized by isotropic negative thermal expansion in ScF3:Tb3+/Eu3+ phosphors ceramics. Specially, a selectively thermal enhanced red emission of Eu3+ from 5D0→7F2 with hypersensitive transition characteristics could be obtained due to the thermal stimulated lattice distortion. Attributing to the shortening of cation spacing, the energy transfer efficiency between Tb3+ and Eu3+ is largely enhanced with the increasing of the temperature from 303 to 473 K. The enhanced energy transfer leads to that the emission of Tb3+ firstly increases and then slightly decreases, whereas the emission from Eu3+ has been largely improved. Finally, an optical temperature sensing strategy based on the fluorescence intensity ratio of the sensitizer Tb3+ (signal ions) and the activator Eu3+ (referring ions) is designed, attributing to the distinguishable luminescence response to the temperature. The obtained maximum relative sensitivity is 1.04 % K−1 (@303 K). Besides, the sensing strategy based on lifetime mode also suggests a maximum relative sensitivity of 1.00 % K−1 at 343 K. It provides a feasible strategy to obtain an optical temperature sensing material with high emission efficiency at a high temperature, which sheds light on the design of luminescence materials keeping high luminescence stability in a wide temperature range in the fields of optical temperature sensing.

Synthesis of organic solvent‐free nitrogen‐doped carbon quantum dots as unique green fluorimetric probes for analysis of abrocitinib in human plasma

AbstractAtopic dermatitis (AD) is a persistent, inflammatory skin condition that impacts approximately 15 to 20% of children and 1 to 3% of adults globally. Common skin manifestations include papules, papulovesicular, and brown or red patches with swelling, crusting, and flaking. Therefore, the drug abrocitinib (ABR) was approved by the US FDA as an oral treatment for atopic dermatitis. The present study outlines the development of innovative, thermostable, and pH‐stable organic solvent‐free nitrogen‐doped carbon dots (N@CQDs) synthesized through a one‐step method for evaluating ABR with a notable quantum yield of 33.84% to minimize the use of organic solvents. Their cost‐effectiveness, eco‐friendly characteristics, and outstanding photocatalytic properties have established them as a promising alternative to conventional luminescent techniques like fluorescent dyes and luminous derivatization technique. The reaction of ABR with N@CQDs led to a significant decrease in the luminescent response of the produced green and stable carbon quantum dots at 513 nm. The detection range was determined to be 1.0–150.0 ng mL−1, with a lower limit of quantitation (LOQ) equal to 0.52 ng mL−1 based on the linear graph. The green method effectively used for analysis of ABR in pharmaceutical tablets and pharmacokinetic study with high sensitivity.

An investigation on the photocatalytic and antibacterial response of green fluorescent carbon dots synthesized from corn flour

Abstract The present work elucidates on a facile hydrothermal synthesis method for producing highly fluorescent carbon dots using corn flour as a natural carbon source. The structural confirmation was validated through XRD (X-ray Diffraction), HR-TEM (High-Resolution Transmission Electron Microscope), and FTIR (Fourier Transform Infra-Red) studies. The synthesized carbon dots exhibited an excitation-dependent photoluminescence (PL) emission. The optical band gap of as-synthesized carbon dots was estimated using UV-absorption spectral analysis. The variation in optical and luminescent response of the carbon dot suspension with the rate of centrifugation was also monitored. Furthermore, investigations on the photocatalytic response of as-synthesized carbon dots towards degradation of methylene blue and its activity as a potential antimicrobial agent against Escherichia coli are also presented.

Luminescent properties and dosimetric behavior of Eu-ion-doped ASO4 (A = Ca, Sr, and Ba)

We investigated the luminescence properties and dosimetric behavior of Eu-ion-doped ASO4 (A = Ca, Sr, or Ba) phosphors synthesized using the coprecipitation method. Structural analysis of the phosphors was performed using X-ray diffraction patterns, which revealed that the prepared samples exhibited a pure phase with diffraction peaks matching those of undoped orthorhombic structures. The luminescence properties of the phosphors were examined by measuring photoluminescence and photoluminescence excitation spectra. We found that both Eu2+ and Eu3+ emissions were detected for A = Ba and Ca, whereas only Eu2+ emission was observed for A = Sr. Further, time-resolved photoluminescence decay curves indicate the presence of Eu2+ and Eu3+ luminescence with different lifetimes. The optically stimulated luminescence (OSL) and thermoluminescence (TL) responses of the samples were investigated. The OSL and TL responses were found to vary linearly with the irradiation dose. This study sheds light on the potential applications of Eu-ion-doped ASO4 phosphors in radiation dosimetry and optoelectronic devices.

Luminescent Response to the Transformation of Zinc Selenide in Ceramic Synthesis

Luminescent Response to the Transformation of Zinc Selenide in Ceramic Synthesis

Binuclear TbⅢ complex used for the fluorescent detection of 2, 6-pyridindicarboxylic acid, an anthrax biomarker

Anthrax is a potentially highly lethal acute infectious disease caused by the zoonotic bacterium Bacillus anthracis, which poses a threat to human life and health. 2, 6-Pyridinedicarboxylic acid (DPA) is a significant component of bacterial spores as a typical anthrax biomarker. Therefore, it is imperative to develop a simple and efficient detection method for DPA. Here, we successfully synthesized a binuclear terbium complex with formulas [Tb2(DMOMP)2(CH3OH)2(H2O)4Cl2]·2Cl·2CH3OH, which is constructed by 2, 6-dimethoxy-4-methylphenol (DMOMP) and TbⅢ ion. Each TbⅢ ion center is encapsulated by seven O atoms and one Cl− anion. Based on this, the encapsulated coordination environment facilitated efficient ligand energy transfer via the “antenna effect”. Therefore, the complex exhibits interesting luminescence response characteristics, with fast and stable green fluorescence response to DPA, low detection limit Ksv = 1.08 × 10−5 M−1, and fluorescence lifetime τ = 754.93 μs. [Tb2(DMOMP)2(CH3OH)2(H2O)4Cl2]·2Cl·2CH3OH has excellent fluorescence properties and strong immunity to interference and is capable of sensitively detecting the B. anthracis biomarker DPA, allowing it to be potentially used as an effective fluorescent probe and providing a viable strategy for effective anthrax fever prevention.

Eu3+-doped manganese tungstate for multiparametric and colorimetric luminescence thermometry

Improvement of luminescent thermometers requires not only the search for high-sensitivity thermometric outputs, but also availability of multiple thermometric parameters affording a combined and reliable response. We hereby detail for the first time the luminescence of Eu3+ in manganese tungstate (Eu3+:MnWO4) solids obtained by coprecipitation under ultraviolet excitation and how this material provided an optical thermometric response from 77 K to 373 K via excitation and emission spectra. Processing of up to five thermometric parameters, namely bandwidths, band positions, band shifts and luminescence intensity ratios, resulted in relative thermal sensitivities as high as 1.56% K−1 and temperature uncertainties between 0.01 and 2 K depending on the choice of the spectral parameter. In addition, we demonstrate that Eu3+:MnWO4 also act as a qualitative colorimetric thermosensor because of progressive change of emission color to greenish-yellow to bluish-green upon heating under UV excitation. Therefore, our results show that the combination of broadband tungstate emissions with the 4f-4f narrow emissions of Eu3+ is an effective approach to achieve a multiparametric luminescent thermal response via emission, excitation and visual observation, which makes Eu3+:MnWO4 a promising candidate for advanced thermometry applications.

A 20-Metal Zn(II)-Cd(II)-Eu(III) Nanocluster with Qualitative and Quantitative Luminescence Detection of Meloxicam (an Anti-Inflammatory Drug).

Meloxicam (MLX) is a novel nonsteroidal anti-inflammatory drug, but on the other hand, it has become one of the common microcontaminants in surface waters and sewage. Herein, we report the preparation of a ternary-metal Zn(II)-Cd(II)-Eu(III) nanocluster 1 for the response of MLX through the enhancement of lanthanide luminescence. The luminescence sensing behavior of 1 is expressed by the equation I615nm = 3060 × [MLX] + 46,604, which can be used in the quantitative analysis of MLX concentrations in meloxicam dispersible tablets. Filter paper strips bearing 1 can be used to qualitatively detect MLX by a color change to red under a UV lamp. The luminescence response time is no more than five s, and the detection limit is as low as 2.31 × 10-2 nM.

“Turn-on” Eu(III) chemosensory polymer materials for ammonia and amines detection: Experimental and molecular modeling study

Polymer films doped by Eu(III) complexes are promising candidates for the development of luminescent chemosensors. Here, luminescent properties of Eu(III) carboxylate dibenzoylmethanates in interaction with ammonia and amine vapors have been studied. Quantitative measurements of the optical response showed that with an increase of the analyte concentration in the range of 3–330 ppm, an increase in the luminescence intensity of europium(III) is observed. The reversibility of the luminescent response is established. Quantum chemical calculations showed that ammonia and amine molecules enter not in the Eu(III) coordination sphere, but forms hydrogen bonds between analyte molecules and carbonyl groups of the dibenzoylmethanate ion. Moreover, analyte changes ligand coordination mode: there occur the transformation from tridentate-bridging-cyclic coordination of carboxyl groups to bidentate-bridging which leads to decreasing in the efficiency of cross-relaxation of lanthanide ions. The obtained “turn-on” chemosensory polymer materials are promising for environmental monitoring and food safety testing.

Construction of a Zn(II)-Eu(III) Nanoring with Temperature-Dependent Luminescence for the Qualitative and Quantitative Detection of Neopterin as an Inflammatory Marker.

A nine-metal Zn(II)-Eu(III) nanoring 1 with a diameter of about 2.3 nm was constructed by the use of a long-chain Schiff base ligand. It shows a luminescence response to neopterin (Neo) through the enhancement of lanthanide emission with high selectivity and sensitivity, which can be used to quantitatively analyze the concentrations of Neo in fetal calf serum and urine. The luminescence sensing of 1 to Neo is temperature-dependent, and it displays more obvious response behavior at lower temperatures. Filter paper strips bearing 1 can be used to qualitatively detect Neo by the color change from chartreuse to red under a UV lamp. The limit of detection is as low as 3.77 × 10-2 nM.

Dual-responsive luminescent dye@MOF hybrids for ratiometric trace detection, colorimetric visualization, and precise discrimination of tetracycline antibiotics

In this work, dual-responsive luminescent Her@Zn-Bim hybrids are developed by herniarin (Her) dye encapsulation engineering within a layered host MOF (Zn-Bim). The pore confinement effect of the Zn-Bim host effectively isolates the guest dye molecules, therefore affording bright blue dye emission for Her@Zn-Bim hybrids. Upon exposure to tetracycline antibiotics (TCs), the hybrid undergoes a significant quenching of the blue emission, concurrent with the appearance of a distinct green emission. This dual-emission response is very fast and sensitive, facilitating real-time ratiometric detection of TCs with a low limit of detection of 7.81 nM. Notably, the ratiometric luminescence response manifests as a readily observable blue-to-green color switching, enabling straightforward and colorimetric visualization of TCs. Visual and semiquantitative monitoring of TCs is achieved using a readily available smartphone installed with a color-analysis app. Furthermore, in conjunction with principal component analysis, the Her@Zn-Bim hybrids demonstrate efficient discrimination of four TCs with high structural and chemical similarities, even in complex mixture systems. The mechanisms underlying the luminescent responses of the hybrids towards TCs are carefully elucidated. These hybrid sensors, featuring high sensitivity, fast response, colorimetric visualization, and precise discrimination capability, hold promising potential for practical applications in sensing TCs.

Lanthanide-grafted covalent organic framework as a colorimetric and luminescence dual-mode nanoprobe for tetracycline detection

Tetracyclines (TCs) are a group of antibiotics commonly using for infection treatment, however, the leftovers in potable water and food which are derived from the abuse of TCs lead to the adverse human health and environmental impacts. Herein, we developed a lanthanide-grafted covalent organic framework (COF) as a colorimetric and luminescence dual-mode nanoprobe to realize precise, sensitive, rapid, real-time TC determination. Ce3+, Eu3+ ions were chosen to functionalize COFs due to their particular corresponding catalytic and luminescent characteristic for bimodal sensing. COF-Ce-Eu can work as an enzyme mimic to catalytically oxidize the substrate of 3,3′,5,5′-tetramethylbenzidine (TMB) with existence of H2O2, besides, the addition of TC is conducive to promote the pristine catalytic activity as the formation of complexation of COF-Ce-Eu with TC. The catalytic activity and the absorbance of COF-Ce-Eu directly correlate to TC concentration. The ratiometric luminescence response was established on the intensity ratio of the broad band centered at 512 nm originated from the matrix COF and the sharp peak at 616 nm originated from Eu3+. The decrease in luminescence intensity of the peak at 512 nm and the increase at 616 nm depended on TC concentration. This colorimetric and luminescence dual-mode platform exhibits excellent selectivity and sensitivity towards TC, with a wide linear range of 0–50 μM, and low detection limits of 24 nM and 3.4 nM, respectively. The designed bimodal sensing strategy provide a promising double assurance for the accurate trace of TC in food and water samples.

Cyclometalated Iridium(III) Complexes Containing Viologen-Modified Phenylpyridine Ligands as Electroluminochromic Active Molecules for Information Display.

Electroluminochromic (ELC) materials have garnered significant research interest because of their potential applications in lighting, displaying, and sensing. These materials exhibit reversible modulation of photoluminescence under low-voltage stimuli. Here five phosphorescent iridium(III) complexes are reported featuring viologen-substituted 2-phenylpyridine (Vppy) ligands acting as electroactive components. Four of the complexes are bis-cyclometalated and coordinated with either neutral bipyridine derivatives or negatively charged 2-picolinate. The remaining complex is heteroleptic tris-cyclometalated, containing one Vppy and two 2-phenylquinoline ligands. Upon photoexcitation, the bis-cyclometalated complexes exhibit orange to red phosphorescence originating from mixed triplet metal-to-ligand charge transfer (3MLCT) and intraligand (3IL) dπ(Ir)/π(Vppy) → π*(Vppy) state, whereas the tris-cyclometalated complex is non-emissive due to a low Ir(IV/III) oxidation potential favoring oxidative quenching by the viologen pendants. When the cationic viologens are electrochemically reduced to their neutral form, the bis-cyclometalated complexes show a remarkable blue-shift in their phosphorescence maxima due to increased energy levels of the Vppy molecular orbitals. In the case of the tris-cyclometalated complex, reduction of the viologen groups interrupts the quenching process, leading to a luminescence turn-on. These complexes are used to develop ELC devices, which exhibit reversible luminescence response in terms of color or on-off switching under a low voltage of 2V.

Fluorinated complexes doped nanodot with high brightness and dual emission for ratiometric detection of glucose-related enzymes

Fluorescence detection of enzymes have attracted considerable interest due to their promise in biological applications, while suffering from the limitation of rigorous demand on the structure design of enzyme substrates. Herein, we report a simple and convenient approach for fluorescence detection of multiple enzymes by developing a fluorescence/phosphorescence dual-emissive nanodot, which is composed of fluorinated organic dyes and fluorinated Pt (II) porphyrin complexes, and exhibits ratiometric luminescence response toward oxygen. We characterized the optical properties of the nanodot, which showed high brightness and sensitive oxygen-response luminescence. Based on the oxygen-consumed enzymatic reaction of glucose oxidase and the glucose-generated enzymatic reaction of the enzymes related to glucose metabolism, and using this presented nanodot, the concentration of glucose and the enzymatic activity of invertase, β-galactosidase, and maltase in aqueous solution were successfully determined quantitatively. To the best of our knowledge, the strategy proposed here for enzyme detection is the first demonstration of an optical probe for monitoring the enzymatic activity of multiple enzymes. Significantly, the strategy presented here may provide a general design principle to develop a kind of luminescent probe for detecting various enzymes.

Donor-acceptor covalent organic polymers as real-time luminescent sensors for detection and removal of nitro-aromatics from an aqueous solution

Creating suitable monitoring probes that exhibit strong fluorescence properties for sensitive detection and effective removal of nitro-aromatics remains a challenge. Herein, triazine-based N-rich donor–acceptor covalent organic polymers (TBN-COPs) with unique electron-rich channels, tunable pore size distribution, and outstanding specific surface areas were rational designed and synthesized for the highly selective detection and effective removal of nitro-aromatics. The sensing properties for electron-deficient benzene derivatives were explored. Compared with other types of TBN-COP candidates, TBN-1 showed a better luminescence response to nitro-aromatics, especially for picric acid (PA). The 0.15 ppm detection limits and 2.89*105 as Ksv could be realized for PA detection by TBN-1. Besides, there were no additional fluorescence responses to the electron rich benzene derivatives, demonstrating the specific selectivity of nitro-aromatics by TBN-1. The energy and charge transfer mechanisms for the hyper nitro-aromatics sensing properties of TBN-1 were further elucidated according to the energy level simulation, and to both the spectroscopic and electrochemical analysis. The merits of TBN-1 are unreservedly manifested when further testing the adsorption performance of TBN-1 for nitro-aromatics removal. The mechanism for the excellent nitro-aromatics adsorption performance of TBN-1 is revealed by coupling model fitting and chemical computation, which indicates the π-π stacking interaction and high electron density of the material to facilitate its combination with nitro-aromatics. Therefore, TBN-1 is a promising candidate to selectively detect and effectively remove nitro-aromatics, and can hence be applied in security checking and environmental conservation.

A novel dual recognition sensor based on molecularly imprinted polymers and photochemical aptamer for non-autofluorescence determination of dopamine

Dopamine (DA), as a neurotransmitter that plays a crucial role in neuronal communication. Abnormal levels of DA concentration in vivo are associated with severe neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Highly selective and highly efficient determination of DA from complex biological samples is very important. In this work, m-MIPs@DA@ZGGC-Apt, a novel sandwich structure persistent luminescence sensor was designed based on a photochemical aptamer sensor and magnetic molecularly imprinted polymers (m-MIPs). By modifying aptamers on the surface of ZGGC persistent luminescent nanoparticles, ZGGC-Apt probes with dual capabilities (recognition and detection) were obtained, which allowed for specific recognition and autofluorescence-free detection of DA. The m-MIPs recognition probe with specific cavity captures of DA was synthesized using Fe3O4 as the imprint carrier. In the presence of both probes, a m-MIPs@DA@ZGGC-Apt sandwich structure was formed continuously in real samples with the increase in DA concentration, resulting in a strong the luminescence response. Under optimal experimental conditions, satisfactory selectivity and sensitivity were obtained by the dual recognition sensor achieved a wide linear range from 0.01 to 100 μM and a low detection limit of 0.0065 μM. Moreover, the designed sensor showed good reliability and practicability in the detection of small molecule DA in real biological samples.

Influence of the synthesis pathway upon the thermoluminescent response of gadolinium aluminate matrix phosphors

The phosphors endowed with a glow curve have a peak much more intense than the others, sensitization to low doses, and a linear relationship between the thermoluminescent response and the dose, which are in demand in the dosimetry market. The gadolinium aluminate has been successfully used as a host lattice of phosphors with luminescent properties. Principally, the luminescent response of the said matrix has been improved by doping with rare earth ions. The thermoluminescent signal depends on the synthesis route because the defect density of a crystal is closely connected to the production pathway that the material went through. Therefore, a crucial step in sensitizing a phosphor is selecting a synthesis route that enhances the efficiency of its thermoluminescent mechanisms. The research herein focused on synthesizing phosphors composed of gadolinium aluminate with no dopant and doped with two molar percent of dysprosium, using two different routes. Among the two synthesis pathways, it was determined to be the most suitable for enhancing the thermoluminescent response of the aforementioned phosphors. The methods employed were reverse coprecipitation and the modified citrate precursor. The phosphors obtained by the reverse coprecipitation method showed the most sensitive thermoluminescent signal. Mainly, the phosphor activated with the dysprosium ion produced the most intense signal, suggesting an improvement in the thermoluminescent mechanisms due to the dopant insertion.

Enhanced Efficiency, Broadened Excitation, and Tailored Er3+ Luminescence Triggered by Te4+ Codoping in Cs2NaYbCl6 Crystals for Multifunctional Applications.

The quest for efficient and tunable luminescent materials has been at the forefront of research in the fields of chemistry and materials science. This work delves into the investigation of the luminescence properties of Er3+ ions triggered by 1% Te4+ in the environmentally benign perovskite Cs2NaYbCl6 (CNYC) crystals, aiming to enhance their efficiency and tune the luminescence color. The ratio of the green (2H11/2, 4S3/2-4I15/2) to red (4F9/2-4I15/2) emissions of Er3+ can be freely tunable by varying the concentration of Er3+ and producing the defects induced by codoping Te4+. The calculations reveal that the multiexcitonic excitations of Er3+ stem from f-f (4I15/2-4G11/2, 2H9/2) rather than d-f transitions. The broadened excitation, tuning of color, and enhancement of efficiency achieved in the luminescence perovskite crystals Cs2NaYbCl6:Te4+, Er3+ (CNYC:Te4+,Er3+) presents promising opportunities for the development of advanced optoelectronic devices with superior performance. Moreover, our investigation demonstrates the tunable luminescence response of CNYC:Er3+ to temperature variations, offering potential applications in temperature sensing.

Synthesis of Eu-doped K0.5Na0.5NbO3 ceramics and their luminescent and dielectric properties

K0.5Na0.5NbO3:xEu sol–gel powders and bulk samples were synthesized by means of a modified sol–gel method. Two types of samples were obtained via sintering at two temperatures. X-ray diffraction revealed the presence of the perovskite phase in materials obtained at both temperatures. Eu3+ emission and excitation studies were conducted to determine its luminescence response. For K0.5Na0.5NbO3:xEu sinters, the excitation spectra included narrow peaks in the VIS range due to the 5D0–7F1 and 5D0–7F2 relaxation processes. These transitions were indicative of the presence of Eu3+ at sites of low symmetry. Dielectric studies indicated that Eu2O3 affected the observed phase transitions. The influence of sintering temperature on structure and physicochemical properties was discussed.

Multicolor Fluorescent Inks Based on Lanthanide Hybrid Organogels for Anticounterfeiting and Logic Circuit Design.

With the rapid development of information technology, the encrypted storage of information is becoming increasingly important for human life. The luminescent materials with a color-changed response under physical or chemical stimuli are crucial for information coding and anticounterfeiting. However, traditional fluorescent materials usually face problems such as a lack of tunable fluorescence, insufficient surface-adaptive adhesion, and strict synthesis conditions, hindering their practical applications. Herein, a series of luminescent lanthanide hybrid organogels (Ln-MOGs) were rapidly synthesized using a simple method at room temperature through the coordination between lanthanide ions and 2,6-pyridinedicarboxylic acid and 5-aminoisophthalic acid. And the multicolor fluorescent inks were also prepared based on the Ln-MOG and hyaluronic acid, with the advantages of being easy to write, color-adjustable, and water-responsive discoloration, which has been applied to paper-based anticounterfeiting technology. Inspired by the responsiveness of the fluorescent inks to water, we designed a logic system that can realize single-input logic operations (NOT and PASS1) and double-input logic operations (NAND, AND, OR, NOR, XOR). The encryption of a binary code can be actualized utilizing different luminescent response modes based on the logic circuit system. By adjusting the energy sensitization and luminescence mechanism of lanthanide ions in the gel structure, the information reading and writing ability of the fluorescent inks were verified, which has great potential in the field of multicolor pattern anticounterfeiting and information encryption.