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Europium-doped boro-telluro-dolomite glasses for red laser applications: Basic insight into spectroscopic traits
摘要： Naturally abundant minerals and lanthanide-doped synthetic boro-tellurite networks have become prospective efficient laser hosts because of the synergy between them. Driven by this idea, Eu3+-doped boro-telluro-dolomite (BTD) glasses were prepared via the melt-quenching method. The spectroscopic traits of as-quenched samples were analyzed though experimental and theoretical studies. The result from the derivation of absorption spectral fitting (DASF) model demonstrated the direct allowed transition in the glasses. Moreover, the photo-luminescence spectra of the sample containing 1.0 mol% of Eu3+ (BTD1.0Eu glass) revealed a prominent red peak at 611 nm (assigned to 5D0 → 7F2 transition in Eu3+ ion) with a large stimulated emission cross section (7.15 × 10?22 cm2) and a high luminescence branching ratio (61.5%). Furthermore, the attained CIE color coordinates (0.637, 0.363), which lie near the standard red hue (0.67, 0.33), together with high quantum efficiency (92.7%) affirmed the effectiveness of BTD1.0Eu glass as a potential red laser host.
关键词： Boro-telluro-dolomite glasses,Red emission,Europium ions,Judd–ofelt analysis,Radiative parameter,Optical band-gap energy
更新于2025-09-16 10:30:52
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Design and optimization of a single-use optical sensor based on a polymer inclusion membrane for zinc determination in drinks, food supplement and foot health care products
摘要： A single-use optical sensor was designed for Zn(II) determination based on the immobilisation of the colorimetric reagent 2-acetylpyridine benzoylhydrazone (2-APBH) in a polymer inclusion membrane (PIM) adhered on the surface of an inert rectangular strip of polyester (Mylar). Different components for the membrane preparation were tested and those resulting in membrane with good appearance, proper physical and optical properties and ease of preparation were selected. Factorial design 23 with three replicates of the central point was applied for the optimisation of the membrane composition. The optimal composition consisted of 2.5 g of poly(vinyl chloride) (PVC), 4 mL of tributyl phosphate (TBP) and 0.04 g of 2-APBH. The optode showed a linear dynamic range from 0.03 (detection limit) to 1 mg L-1 of Zn(II) ions with a response time of 30 min in aqueous solution at pH 6 and a relative standard deviation of 3.90% for 0.4 mg L-1 of Zn(II). The sensor exhibited good selectivity to Zn(II) over other commonly ions. It was successfully applied to the determination of Zn(II) in a water certified reference material, spiked tap water, vitamin-mineral drink, food supplement and foot health care products, as contribution to the concern about this heavy metal due to its significant role in many biological and physiological processes although toxicant at high doses.
关键词： 2-acetylpyridine benzoylhydrazone,Zn(II) ions determination,optical sensor,PVC matrix,polymer inclusion membrane
更新于2025-09-16 10:30:52
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Near-infrared Laser Triggered Full-Color Tuning Photon Upconversion and Intense White Emission in Single Gd2O3 Microparticle
摘要： Full-color emission fluorescence materials are of imperious demands in information storage, graphics imaging and anti-counterfeiting fields. However, it is still a formidable challenge to develop a single material with full-color emission and high purity white output under a NIR-light excitation. Herein, we design a novel and convenient strategy to tune the upconversion luminescence color with full color range in lanthanide ions doped Gd2O3 microspheres via a single NIR laser sensitization. Different from the typical ion-dependent tuning of color, the bright and flexible full-color emission tuning from blue to cyan, green, yellow, pink, and red can be controllable implementation in a single microparticle. Particularity, benefiting from the laser sensitive color adjustment, highly intense white color emission can be simultaneously achieved in diverse doped ion concentration particles. In addition, the upconversion emission intensity has been evidently improved if using a NIR laser sensitization, leading to significantly enhanced upconversion red luminescence signal (44-fold) at the power 446 mW. The mechanistic investigations and dynamics analysis reveal that the unprecedented color tunability from these microcrystals is attributed to dynamic control of multi-energy transfer and multi-cross relaxation process. Furthermore, owning to their excellent upconversion luminescence properties, Gd2O3 microparticles could be used to the anticounterfeiting application in different colors. These findings not only open a way to fabricate a single material to fine tuning upconversion emission in a full color gamut, but also give the possibility to construction of the multicolor imaging for anti-counterfeiting applications.
关键词： upconversion luminescence,anti-counterfeiting,full color emission,lanthanide ions doped Gd2O3 microspheres,white color emission,laser sensitization
更新于2025-09-16 10:30:52
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Coherent laser spectroscopy of highly charged ions using quantum logic
摘要： Precision spectroscopy of atomic systems1 is an invaluable tool for the study of fundamental interactions and symmetries2. Recently, highly charged ions have been proposed to enable sensitive tests of physics beyond the standard model2–5 and the realization of high-accuracy atomic clocks3,5, owing to their high sensitivity to fundamental physics and insensitivity to external perturbations, which result from the high binding energies of their outer electrons. However, the implementation of these ideas has been hindered by the low spectroscopic accuracies (of the order of parts per million) achieved so far6–8. Here we cool trapped, highly charged argon ions to the lowest temperature reported so far, and study them using coherent laser spectroscopy, achieving an increase in precision of eight orders of magnitude. We use quantum logic spectroscopy9,10 to probe the forbidden optical transition in 40Ar13+ at a wavelength of 441?nanometres and measure its excited-state lifetime and g-factor. Our work unlocks the potential of highly charged ions as ubiquitous atomic systems for use in quantum information processing, as frequency standards and in highly sensitive tests of fundamental physics, such as searches for dark-matter candidates11 or violations of fundamental symmetries2.
关键词： precision spectroscopy,fundamental physics,quantum logic spectroscopy,highly charged ions,atomic clocks
更新于2025-09-16 10:30:52
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Simultaneous detection of mercury (II), lead (II) and silver (I) based on fluorescently labelled aptamer probes and graphene oxide
摘要： We have developed a fluorescence quantitative analysis method for the simultaneous detection of Hg2+, Pb2+ and Ag+ based on fluorescently labeled nucleic acid aptamer probes and graphene oxide. By this method, three nucleic acid aptamer probes (PHg, PPb, PAg) were designed. The carboxyl fluorescein (FAM), tetramethyl-6-carboxyrhodamine (TAMRA) and cyanine-5 (Cy-5) were respectively selected as fluorophore of aptamer probes, and graphene oxide (GO) was chosen as quencher. In general, these probes were on free single-stranded state and adsorbed on the surface of GO via π-π interactions, which brought fluorophores of probes and GO into close proximity. Due to the fluorescence resonance energy transfer (FRET) occurred between fluorophores and GO, the fluorescence was quenched and fluorescence signals were all weak. Under the optimal condition, fluorescence intensities of three fluorophores exhibited a good linear dependence on corresponding ions concentration. The detection limit for Hg2+, Pb2+ and Ag+ were 0.2 nmol/L, 0.5 nmol/L and 2 nmol/L (3σ, n=11). Average recoveries of this method were 97.56 - 104.92%, which indicated the method had a high accuracy and low detection limit. In addition, this proposed method has good selectivity, and there was no crosstalk effect among these probes.
关键词： Graphene oxide,Simultaneous detection,Metal ions,Fluorescence,Aptamer
更新于2025-09-16 10:30:52
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Electrochemical sensing of mercury ions in electrolyte solutions by nitrogen-doped graphene quantum dot electrodes at ultralow concentrations
摘要： Electrochemical detection of mercury ions in aqueous solution was investigated at indium tin oxide (ITO) conducting glass electrode modified by nitrogen-doped graphene quantum dots (N-doped GQDs). The N-doped GQDs with an average particle size of 4.5 nm were synthesized through an infrared-assisted pyrolysis of citric acid and urea at 250°C. The GQD sample contains high oxidation and amidation level, i.e., O/C and N/C atomic ratios: 37.6% and 30.7%, respectively. The electrochemical sensing toward Hg2+ ions was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Based on the CV and EIS analyses, both the reductive and oxidative peak currents as well as the equivalent series resistance demonstrate a decreasing trend with increased Hg2+ concentration. The detection limit of N-doped GQD/ITO electrodes toward Hg2+ ions reached 10 ppb with the accumulation time of 32 s. The GQD/ITO electrodes also exhibit superior selectivity toward the target contaminant (i.e. Hg2+ ion). Accordingly, the functionalized GQDs pave the way for engineering the electrochemical sensors capable of detecting toxic Hg2+ ions with superb sensitivity and selectivity.
关键词： Nitrogen doping,Electrolyte solution,Infrared-assisted synthesis,Graphene quantum dots,Mercury ions
更新于2025-09-16 10:30:52
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lasers
摘要： The Tm,Ho:Lu2O3 crystal was grown by the optical floating zone method for the first time. The XRD pattern shows that it belongs to the cubic crystal system (Ia￣3 space group). The absorption cross-section at 796 nm is 10 21 cm2, the full width at half maximum (FWHM) is 54 nm. The emission cross-section at 2092 nm is 4.21 2. The broad fluorescence band extends to 2200 nm where almost no absorption was found. The fluoresce lifetime at 2092 nm is 3.73 ms. With the help of up-conversion spectra, the energy transfer mechanism between Tm3+ and Ho3+ ions was investigated systematically. The potential utility of the Tm,Ho:Lu2O3 crystal as tunable and ultra-short laser media at ~2.1 μm can be expected.
关键词： Lu2O3,Ho3+ ions,Crystal growth,Tm3+ ions
更新于2025-09-12 10:27:22
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The physics of ion migration in perovskite solar cells: Insights into hysteresis, device performance, and characterization
摘要： Perovskite solar cells promise to reach the highest efficiencies at the lowest costs, but the mobile ions create challenges in both cell measurements and performance improvement. Being able to understand the ion migration mechanism and its impacts would help to solve relevant issues and may open up opportunities for further development. Although some efforts have been made here, explanations are often too exotic resulting in not only some controversies but the neglect of some important aspects addressable by familiar concepts. This paper uses familiar knowledge in solar cell device physics to explain the ion migration mechanism and its impacts under conditions of interests. It is shown that, when depletion layers contract such as in a forward current‐voltage scan, tardy ionic charges can distort the perovskite bands hence reduce the net currents before they move to new equilibriums, causing the hysteresis effect. As ion migration impacts the electron and hole distributions, it can affect the Shockley‐Read‐Hall and Auger processes differently, hence may either reduce or increase the ratio of radiative to nonradiative recombination. This previously unaddressed mechanism for variation in the electron‐hole recombination can explain photoluminescence quenching and enhancement as well as performance degradation and improvement during ion migration.
关键词： perovskite solar cells,ions,luminescence,recombination,hysteresis
更新于2025-09-12 10:27:22
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Spatial charge relaxation in glasses poled in the air and argon atmospheres
摘要： Thermal poling of a multicomponent silicate glass was performed in air and in argon atmospheres at various voltages, and the temperature dependences of the depolarization currents (TSDC) in the poled glasses were studied. In addition, the concentration profiles of univalent and bivalent cations in subanodic regions of the poled glasses were measured with EDS and SIMS techniques. The difference in the displacements of bivalent ions at poling of the glasses in closed and open anode configurations allowed us to identify “frozen” spatial charge relaxation peaks observed in the TSDC measurements and to relate these peaks to hydrogen and bivalent metal ions relaxation.
关键词： spatial charge relaxation,silicate glass,thermal poling,depolarization currents,hydrogen and bivalent metal ions relaxation
更新于2025-09-12 10:27:22
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Controlling multiphoton excited energy transfer from Tm <sup>3+</sup> to Yb <sup>3+</sup> ions by a phase-shaped femtosecond laser field
摘要： The ability to control the energy transfer in rare-earth ion-doped luminescent materials is very important for various related application areas such as color display, bio-labeling, and new light sources. Here, a phase-shaped femtosecond laser field is first proposed to control the transfer of multiphoton excited energy from Tm3+ to Yb3+ ions in co-doped glass ceramics. Tm3+ ions are first sensitized by femtosecond laser-induced multiphoton absorption, and then a highly efficient energy transfer occurs between the highly excited state Tm3+ sensitizers and the ground-state Yb3+ activators. The laser peak intensity and polarization dependences of the laser-induced luminescence intensities are shown to serve as proof of the multiphoton excited energy transfer pathway. The efficiency of the multiphoton excited energy transfer can be efficiently enhanced or completely suppressed by optimizing the spectral phase of the femtosecond laser with a feedback control strategy based on a genetic algorithm. A (1 + 2) resonance-mediated three-photon excitation model is presented to explain the experimental observations. This study provides a new way to induce and control the energy transfer in rare-earth ion-doped luminescent materials, and should have a positive contribution to the development of related applications.
关键词： energy transfer,rare-earth ions,femtosecond laser,luminescent materials,multiphoton absorption
更新于2025-09-12 10:27:22