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Yb <sup>3+</sup> /Ln <sup>3+</sup> /Mn <sup>4+</sup> (Ln = Er, Ho, and Tm) doped Na <sub/>3</sub> ZrF <sub/>7</sub> phosphors: oil–water interface cation exchange synthesis, dual-modal luminescence and anti-counterfeiting
摘要： Efficient dual-modal luminescence is highly desired for applications in high security anti-counterfeiting. In the present work, Yb3+/Ln3+/Mn4+ (Ln = Er, Ho, and Tm) tri-doped Na3ZrF7 phosphors were fabricated via oil–water interface cation exchange using Yb3+/Ln3+:Na3ZrF7 as the exchanging hosts. The as-prepared products exhibited typical Mn4+ red down-shifting luminescence under UV light excitation and Er3+ red, Ho3+ yellow and Tm3+ near-infrared multi-color upconversion emissions under 980 nm laser excitation. The Mn4+ dopants in the Na3ZrF7 host experienced strong crystal-field strength Dq of 3.63 and showed superior thermal stability with up to 90% of the initial emission intensity retained at 448 K. Steady-state and time-resolved emission spectra verified that there was no detrimental energy transfer interaction between Mn4+ and Ln3+, enabling bright and eye-visible bi-functional emissions for the present products. As a consequence, the as-prepared phosphors were demonstrated to be applicable in anti-counterfeiting by a proof of concept experiment of fluorescent labeling for specially designed patterns.
关键词： phosphors,upconversion,anti-counterfeiting,cation exchange,dual-modal luminescence
更新于2025-11-20 15:33:11
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Grinding Synthesis of APbX3 (A=MA, FA, Cs; X=Cl, Br, I) Perovskite Nanocrystals
摘要： Currently, metal halide perovskite nanocrystals have been extensively explored due to their unique optoelectronic properties and wide application prospects. In the present work, a facile grinding method is developed to prepare whole-family APbX3 (A=MA, FA and Cs; X=Cl, Br and I) perovskite nanocrystals. This strategy alleviates the harsh synthesis conditions of precursor dissolution, atmosphere protection and high temperature. Impressively, the as-prepared perovskite nanocrystals are evidenced to have halogen-rich surfaces and yield visible full-spectral emissions with maximal photoluminescence quantum yield up to 92% and excellent stability. Additionally, the grinding method can be extended to synthesize widely concerned Mn2+-doped CsPbCl3 nanocrystals with dual-modal emissions of both excitons and dopants. As a proof-of-concept experiment, the present perovskite nanocrystals are demonstrated to be applicable as blue/green/red color converters in UV-excitable white-light-emitting diode.
关键词： perovskite,CsPbBr3,optical materials,luminescence,LED
更新于2025-11-20 15:33:11
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Energy transfer in and fluorescence studies of the Eu-Tb doped BPA-phen system
摘要： To enhance the red emission efficiency of Eu3+ complexes, [Eu/Tbx(BPA)3phen] (BPA = bisphenol A, phen = 1,10-phenanthroline) is designed and synthesized. The complexes are characterized fully and their luminescence properties are evaluated. Co-fluorescence is detected in the Eu/Tbx(BPA)3phen complexes, and the existence of Tb3+ enhances the luminescence intensity of the central Eu3+ because of the intramolecular energy transfer from the 5D4 level of Tb3+ to the 5D0 level of Eu3+. The luminescence intensity of europium ions at 615 nm is the highest for Eu/Tb1(BPA)3phen. To improve the thermal stabilities and mechanical properties of pure complexes, Eu/Tb1(BPA)3phen/PAN (PAN = polyacrylonitrile) is used to fabricate fibres by electrospinning. Compared with Eu/Tb1(BPA)3phen (τ = 1.1087 ms), the fibres have a longer fluorescence lifetime of 1.533 ms. The fibres also retain a high quantum yield of 47.16%. Thus, the flexible luminescent fibres have potential applications in many fields.
关键词： electrospinning,Bisphenol A,energy transfer,luminescence
更新于2025-11-20 15:33:11
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Two pH-responsive fluorescence probes based on indole derivatives
摘要： Two new pH ?uorescent probes 2,8-bis((E)-2-(1,1-dimethyl-1H-benzo[e]indol-2-yl)vinyl)-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine (1) and 2,8-bis((E)-2-(3,3-dimethyl-3H-indol-2-yl)vinyl)-6H,12H-5,11-methanodibenzo[b,f] [1,5]diazocine (2) were designed and synthesized via ethylene bridging of the Tr?ger's Base (TB) framework and indole derivatives. As the protonation of nitrogen atoms of indole derivatives, both probes displayed the signi?cant pH-dependent spectral properties. The probing behavior toward pH variations indicated that probes exhibited excellent pH dependent behavior in the pH ranges of 2.07–7.01 (1) and 1.96–7.01 (2), especially possessing good linear response in the pH ranges of 2.50–4.00. The emissions of 1 can be reversibly switched between brilliant yellow and dark states by protonation and deprotonation. Also, the yellow-green ?uorescence emission of 2 could be quenched upon protonation. Such behaviors enable them to work as turn-o? ?uorescent pH sensors in the solution state. Furthermore, protonation and deprotonation on indole moiety nitrogen of the probe 1 and 2 provided a sensing mechanism for pH changes. In addition, both probes performed good photostability, high selectivity and excellent reversibility.
关键词： Sensors,Fluorescent probe,pH detection,Luminescence,Indole derivatives
更新于2025-11-19 16:56:35
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A novel photocatalyst, Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3, for highly efficient photocatalytic hydrogen evolution under visible-light irradiation
摘要： In this work, Y2SiO5:Pr3+,Li, as an excellent up-conversion luminescence agent from visible-light to ultraviolet-light, is synthesized by using sol-gel method. And then, a series of Y2SiO5:Pr3+,Li/NaNbxTa1?xO3 (x = 0.00, 0.25 and 0.50) with different amounts of Y2SiO5:Pr3+,Li are prepared by using hydrothermal method. The prepared samples are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV–vis absorption spectroscopy and photoluminescence spectroscopy (PL). The activities of Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3 are investigated through photocatalytic hydrogen evolution in 10 vol% methanol solution under visible-light irradiation. The influences of Nb content in NaNbxTa1?xO3, mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3, visible-light irradiation time and reuse-times are examined on the visible-light photocatalytic hydrogen evolution. The experimental results showed that the prepared Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3 with 0.4:1.0 mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3 and 0.25 wt% Pt loading displayed a highest evolved hydrogen activity under visible-light irradiation. This study may provide some significant references for large scale photocatalytic hydrogen evolution utilizing solar energy.
关键词： Visible-light photocatalyst (Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3),Photocatalytic hydrogen evolution,Pt loading,Nb-substituted NaTaO3,Up-conversion luminescence agent (Y2SiO5:Pr3+,Li)
更新于2025-11-19 16:51:07
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An anti-symmetric dual (ASD) Z-scheme photocatalytic system: (ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4) for organic pollutants degradation with simultaneous hydrogen evolution
摘要： An anti-symmetric dual (ASD) Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst was prepared by isoelectric point and calcination methods. The photocatalytic activity is estimated via degradation of Acid Orange II as a target organic contaminant with simultaneous hydrogen evolution under simulated solar-light irradiation. The prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst has a high photocatalytic activity, which can be assigned to the enlarged photoresponse range, increased reduction surface and enhanced separation efficiency of photo-induced carriers. Furthermore, the cyclic experiment proves that the prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst still maintains a high photocatalytic activity within five repetitive cycles. Moreover, the mechanism on photocatalytic degradation of organic pollutants with simultaneous hydrogen evolution caused by ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst is proposed. It is wished that this study could provide a promising pathway for effective degradation and rapid hydrogen production.
关键词： Simultaneous hydrogen evolution,Organic contaminants,Anti-symmetric dual (ASD) Z-scheme photocatalytic system,ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 composite,Up-conversion luminescence agent,Photocatalytic degradation
更新于2025-11-19 16:51:07
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Dual-band luminescent solar converter-coupled dye-sensitized solar cells for high performance semi-transparent photovoltaic device
摘要： We demonstrate a high-performance semi-transparent solar cell using a dye-sensitized solar cell (DSSC) coupled with a luminescent solar converter (LSC) that absorbs a dual band. We present an architecture of a sandwich-type, downshift (DS) LSC / DSSC / upconversion (UC) LSC. The DS LSC, including anthracene, converts ultraviolet light to visible light, and the UC LSC, which contains a dye pair of meso-tetraphenyl-tetrabenzoporphine palladium / 9,10-bis-penylethynyllanthrancane, converts near-infrared light into visible light. Thus, the dual band LSC improved the power conversion efficiency (PCE) of the DSSC without a significant decrease in visible transmittance. We optimize the concentration of the fluorescence dye to obtain maximum photoluminescence in each LSC. We also optimize backward scattering by introducing nanoparticle scatterers in UC LSC. The dual LSC-DSSC showed an average visible transmittance of 42% and achieved an PCE of up to 7.8%. Our incorporation of broadband-wavelength-harvestable LSCs with a DSSC presents a direction for semi-transparent photovoltaic devices.
关键词： Luminescence solar concentrator,Semi-transparent photovoltaic devices,Downshift,Photon upconversion,Dye-sensitized solar cells
更新于2025-11-19 16:46:39
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Ultrasonic-Assisted Synthesis of a Zn(II) Coordination Polymer in Aqueous Media and Its High-Performance Luminescent Sensing for 2,4,6-Trinitrophenol
摘要： A novel Zn(II) coordination polymer based on 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol (Hpzt), namely [Zn(pzt)2]n or (Zn-CP), was synthesized by two different synthetic methods. The bulk polycrystals and single-crystals of Zn-CP were obtained by the conventional solvothermal method at 90°C. The Zn-CP exhibits a two-dimensional (2D) coordination network that contains the uncoordinated Lewis basic sites within each layer. Interestingly, a simple environmentally friendly sonochemical synthesis of the Zn-CP in an aqueous media could be performed at room temperature. The optimal synthetic conditions were studied. The uniform microplates of Zn-CP were obtained within 30 min with the addition of pyridine, acting as a sized modulator and a deprotonating reagent. The influence of the amount of the modulator and the sonication time on their crystalline size was investigated. Moreover, the Zn-CP suspension in an ethanolic media has been used as a luminescence sensor for the detection of nitroaromatic compounds. It shows highly selective and sensitive sensing of 2,4,6-trinitrophenol (TNP) through the quenching (turn off) process under the UV light. Also, the Zn-CP microplates show the higher dispersibility and more stable suspension than those of bulk products causing an increase of the luminescent sensing performance for TNP.
关键词： 2,sonochemical synthesis,4,Zn(II),Coordination polymer,luminescence,6-trinitrophenol
更新于2025-11-19 16:46:39
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Latent fingermark detection using functionalised silicon oxide nanoparticles: Method optimisation and evaluation
摘要： The application of nanoparticles for latent fingermark detection has been reported in the literature over the past two decades. One of the nanoparticles that shows promise to become a routine technique is functionalised silicon oxide nanoparticles (SiO2 NPs). In a recent optimisation of the technique, the use of carboxyl-functionalised SiO2 NPs doped with luminescent ruthenium complex was proposed as a breakthrough for latent fingermark detection. In this study, the aforementioned functionalised SiO2 NPs were extensively evaluated. Modification and optimisation of the original detection parameters were performed to enhance detection quality and improve applicability. Various detection parameters were evaluated and assessed. A lower concentration of the functionalised nanoparticles used in the colloidal dispersion was determined to offer improved detection effectiveness. A combination of increased bath temperature and reduced immersion time was found to produce good overall results. A set of modified detection parameters was suggested for the use of the functionalised SiO2 NPs to detect latent fingermarks. Performance of the modified detection parameters was compared against that of the published detection method. Comparison experiments were carried out on fingermark specimens deposited on aluminium foil, transparent polypropylene plastic and green polyethylene plastic. Three donors (weak, average and strong) and two age intervals (ten days and three months) were considered in the comparison study. Evaluation of the results suggested that the overall performance of the modified method for latent fingermark detection was superior to that obtained using the previously published detection parameters.
关键词： Bath temperature,Detection effectiveness,Method modification,Colloidal,Surface functionalisation,Luminescence technique
更新于2025-11-19 16:46:39
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Luminescence and electrical properties of Eu-modified Bi <sub/>0.5</sub> Na <sub/>0.5</sub> TiO <sub/>3</sub> multifunctional Ceramics
摘要： The Eu3+ modified Bi0.5Na0.5TiO3 (BNT) ceramics have been fabricated by the solid-state reaction method. The impact of Eu3+ doping on the structure, photoluminescence and electrical properties has been studied by XRD, SEM, PL spectra and LCR meter. X-ray diffraction analysis reveals that the crystal structure of the samples is well matched with the trigonal perovskite, and the optimal temperature of pre-sintering is 880°C. The Eu3+ doped BNT ceramics show excellent red fluorescence at 614nm corresponding to the 5D0→7F2 transition of Eu3+ under 466nm excitation and relatively long fluorescence lifetime. The BNT-0.02Eu ceramic density is up to 5.68g/cm3 and the relative density is up to 94.6% with sintering temperature 1075°C. The piezoelectric constant (d33) of samples has been significantly improved up to 110pC/N by Eu3+ doping. The BNT-0.03Eu ceramic pre-sintered at 880°C and sintered at 1050°C has good dielectric properties and excellent luminescence properties. Eu3+ doped BNT ceramics make it potential applications for novel integrated optical-electro and multifunctional devices.
关键词： luminescence,electrical properties,Bismuth sodium titanate (Bi0.5Na0.5TiO3),lead-free ceramics
更新于2025-11-14 17:28:48