Tunable photoluminescence and magnetic properties of Dy(3+) and Eu(3+) doped GdVO4 multifunctional phosphors

Photoluminescence processes in τ-phase Ba1.3Ca0.7-x-y SiO4:xDy 3+/yTb3+ phosphors for solid-state lighting

The τ-phase Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ phosphors co-doped with Dy ³⁺ (x = 0.03) and Tb³⁺ (y = 0.01-0.05) trivalent rare-earth ions were prepared by the gel-combustion method. The structure-property relation of the samples was examined by X-ray diffraction, scanning electron microscopy and spectrophotometer. Here, the effect of Tb³⁺'s concentration on the spectroscopic properties of Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ phosphors was explored by using the photoluminescence excitation, emission and decay curves. Importantly, the photonic energy transfer from (Dy ³⁺:⁴F_9/2 + Tb³⁺:⁷F₆) to (Dy ³⁺:⁶H_15/2 + Tb³⁺:⁵D₄) was observed, in which the Dy ³⁺ ions act as a light-emitting donor whereas the Tb³⁺ ions as a light-absorbing acceptor, resulting in an enhanced emission from the co-doped Ba_1.3Ca_0.7-x-y SiO₄:xDy ³⁺/yTb³⁺ (x = 0.03 and y = 0.01-0.05) phosphors. Finally, the chromaticity coordinates were determined from the measured emission spectra, locating at the green and white light regions. This observation indicates that the characteristic emission colour could be tuned from white to green by varying Tb³⁺ concentrations under ultraviolet light.

Highly Sensitive Lanthanide-Doped Nanoparticles-Based Point-of-Care Diagnosis of Human Cardiac Troponin I

Introduction

Methods

Results

Conclusion

Self-reduction synthesis and luminescence properties of Eu, Dy co-doped SrMg2 (PO4 )2 phosphor

A series of SrMg₂ (PO₄ )₂ :Eu²⁺ -Eu³⁺ ,Dy³⁺ phosphors was synthesized successfully using a high-temperature solid-state method in an air atmosphere. The structures were studied in detail using X-ray diffraction (XRD) and the luminescence properties of the samples. SrMg₂ (PO₄ )₂ :Eu²⁺ -Eu³⁺ samples can emit adjustable blue-violet light by controlling the proportion of dopant concentration of europium and dysprosium under 340 nm excitation. Dy³⁺ exhibits typical blue and yellow emission under 350 nm excitation. The energy transferred from Eu³⁺ to Dy³⁺ in Dy and Eu co-doped system was determined by comparing the fluorescence spectra of single-doped system. In addition, the colour coordinates of the International Commission on lighting (CIE) indicated that SrMg₂ (PO₄ )₂ :Eu²⁺ -Eu³⁺ ,Dy³⁺ could be considered as a potential blue-purple phosphor for white light-emitting diode applications.

Ionic liquid/H2O two-phase synthesis and luminescence properties of BaGdF5:RE3+ (RE = Ce/Dy/Eu/Yb/Er) octahedra

BaGdF₅:RE³⁺ (RE = Ce/Dy/Eu) octahedra were synthesized via a facile ionic liquid/H₂O two-phase system. Multi-color emissions have been realized.

Up-conversion of lanthanide ions and down-conversion defect luminescence in BaGdF5:Yb,Er/Tm for application in anti-counterfeiting

BaGdF5:Yb,Er/Tm was prepared using a one-pot hydrothermal method, and the anti-counterfeiting patterns obtained by screen printing have dual-mode luminescence.

Highly Water-Soluble Luminescent Silica-Coated Cerium Fluoride Nanoparticles Synthesis, Characterizations, and In Vitro Evaluation of Possible Cytotoxicity

A coprecipitation process was utilized for the preparation of terbium fluoride nanocrystals by cerium fluoride. Silica was used to modify the surface of these core/shell nanocrystals. The synthesized CeF₃:Tb@LaF₃ and CeF₃:Tb@LaF₃@SiO₂ nanoparticles (NPs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV/vis spectrophotometry, and photoluminescence spectrophotometry. XRD patterns showed resolved reflection planes with broad widths, confirming the nanocrystalline nature of the CeF₃:Tb@LaF₃@SiO₂ NPs. Fourier transform infrared spectra clearly revealed a uniform, smooth silica layer encapsulating the luminescent seed core and confirmed the polycrystalline nature of the CeF₃:Tb@LaF₃@SiO₂ NPs. The TEM result showed an average crystalline size of 18 nm, which illustrated good agreement with the XRD results. The results of photoluminescence spectrophotometry confirmed the doping of terbium ions in the CeF₃ crystal lattice. The cytotoxicity results of the MTT assay showed that CeF₃:Tb@LaF₃@SiO₂ NPs have minimum toxicity with respect to CeF₃:Tb@LaF₃ NPs and the control drug dasatinib on HT-29 and HepG2 cell lines. Moreover, results of inverted microscopy confirmed the nontoxic and biocompatible nature of CeF₃:Tb@LaF₃@SiO₂ NPs. These findings show that CeF₃:Tb@LaF₃@SiO₂ NPs are promising candidates for applications in biomedical science in the future, such as bioimaging, biolabeling, biodetection or bio-probing, labeling of cells and tissue, drug delivery, cancer therapy, and multiplexed analysis.

Bimodal Nd-Doped LuVO4 Nanoprobes Functionalized with Polyacrilic Acid for X-Ray Computed Tomography and NIR Luminescent Imaging

Uniform Nd3+-doped LuVO4 nanophosphors have been synthesized for the first time in literature by using a poliol-based method at 120 °C from Nd3+ and vanadate precursors. After optimizing the Nd doping level, these phosphors present intense luminescence in the near-infrared biological windows. The X-ray attenuation capacity of the optimum nanophosphor has been found to be higher than that of a commercial X-ray computed tomography contrast agent. After surface coating with polyacrylic acid, such nanoparticles present high colloidal stability in physiological pH medium and high cell viability. Because of these properties, the developed Nd3+-doped LuVO4 nanoparticles have potential applications as a bimodal probe for NIR luminescent bioimaging and X-ray computed tomography.

An efficient down conversion luminescencent probe based on a NaGdF4:Eu3+/Ce3+ nanophosphor for chemical sensing of heavy metal ions (Cd2+, Pb2+ and Cr3+) in waste water

Eu³⁺ doped and Eu³⁺/Ce³⁺ co-doped NaGdF₄ nanophosphors are fabricated via a facile hydrothermal route. The codoped counterpart is demonstrated for efficient photoluminescence sensing of heavy metal ions (Cd²⁺, Pb²⁺ and Cr³⁺) present in industrial effluents.

Highly Efficient Transparent Nanophosphor Films for Tunable White-Light-Emitting Layered Coatings

Bright luminescence in rare-earth (RE) nanocrystals, the so-called nanophosphors, is generally achieved by choosing a host that enables an effective excitation of the RE activator through charge or energy transfer. Although tungstate, molybdate, or vanadate compounds provide the aforementioned transfer, a comparative analysis of the efficiency of such emitters remains elusive. Herein, we perform a combined structural and optical analysis, which reveals that the tetragonal GdVO₄ matrix gives rise to the highest efficiency among the different transparent nanophosphor films compared. Then, we demonstrate that by a sequential stacking of optical quality layers made of Eu³⁺- and Dy³⁺-doped nanocrystals, it is possible to attain highly transparent white-light-emitting coatings of tunable shade with photoluminescence quantum yields above 35%. Layering provides a precise dynamic tuning of the chromaticity based on the photoexcitation wavelength dependence of the emission of the nanophosphor ensemble without altering the chemical composition of the emitters or degrading their efficiency. The total extinction of the incoming radiation along with the high quantum yields achieved makes these thin-layered phosphors one of the most efficient transparent white converter coatings ever developed.

Role of Dy3+ → Sm3+ energy transfer in the tuning of warm to cold white light emission in Dy3+/Sm3+ co-doped Lu3Ga5O12 nano-garnets

Nano-crystalline lutetium gallium garnets co-doped with Dy³⁺ and Sm³⁺ ions have been synthesized via a sol–gel method and their structural, morphological and luminescence properties have been characterized.

Facile synthesis and color-tunable properties of monodisperse β-NaYF4:Ln3+ (Ln = Eu, Tb, Tm, Sm, Ho) microtubes

In this study, monodisperse and uniform β-NaYF₄ hexagonal microtubes were successfully synthesized via a simple hydrothermal method without any organic surfactants, employing Y(OH)CO₃ colloid spheres as precursors.

Morphology/phase controllable synthesis of monodisperse ScVO4 microcrystals and tunable multicolor luminescence properties in Sc(La)VO4(PO4):Bi3+,Ln3+ phosphors

A facile one-pot hydrothermal approach was employed to prepare novel chocolate-like ScVO₄ microcrystals using polyethylene glycol as an additive.

Multifunctional GdVO4:Eu core–shell nanoparticles containing 225Ac for targeted alpha therapy and molecular imaging

Development of actinium-225 doped Gd_0.8Eu_0.2VO₄ core–shell nanoparticles as multifunctional platforms for multimodal molecular imaging and targeted radionuclide therapy.

A novel optical thermometry based on the energy transfer from charge transfer band to Eu3+-Dy3+ ions

Optical thermometry based on the up-conversion intensity ratio of thermally coupled levels of rare earth ions has been widely studied to achieve an inaccessible temperature measurement in submicron scale. In this work, a novel optical temperature sensing strategy based on the energy transfer from charge transfer bands of W-O and Eu-O to Eu³⁺-Dy³⁺ ions is proposed. A series of Eu³⁺/Dy³⁺ co-doped SrWO₄ is synthesized by the conventional high-temperature solid-state method. It is found that the emission spectra, emission intensity ratio of Dy³⁺ (572 nm) and Eu³⁺ (615 nm), fluorescence color, lifetime decay curves of Dy³⁺ (572 nm) and Eu³⁺ (615 nm), and relative and absolute sensitivities of Eu³⁺/Dy³⁺ co-doped SrWO₄ are temperature dependent under the 266 nm excitation in the temperature range from 11 K to 529 K. The emission intensity ratio of Dy³⁺ (572 nm) and Eu³⁺ (615 nm) ions exhibits exponentially relation to the temperature due to the different energy transfer from the charge transfer bands of W-O and Eu-O to Dy³⁺ and Eu³⁺ ions. In this host, the maximum relative sensitivity S_r can be reached at 1.71% K⁻¹, being higher than those previously reported material. It opens a new route to obtain optical thermometry with high sensitivity through using down-conversion fluorescence under ultraviolet excitation.

Hydrothermal synthesis, down-/enhanced up-converting, color tuning luminescence, energy transfer and paramagnetic properties of Ln3+ (Ln = Eu/Dy, Yb/Ho)-doped Ba2GdF7 multifunctional nanophosphors

Tunable multicolor, energy transfer processes, and paramagnetic properties of the Ba₂GdF₇:Ln³⁺ (Ln = Eu/Dy, and Yb/Ho) nanophosphors were studied.

Assembly of 1D nanofibers into a 2D bi-layered composite nanofibrous film with different functionalities at the two layers via layer-by-layer electrospinning

A unique bi-layered composite nanofibrous film with trifunctionality of electrical conduction, magnetism and photoluminescence has been fabricated via layer-by-layer electrospinning.

An electrospun flexible Janus nanoribbon array endowed with simultaneously tuned trifunctionality of electrically conductive anisotropy, photoluminescence and magnetism

A flexible Janus nanoribbon array endowed with simultaneously tuned trifunctionality of electrically conductive anisotropy, photoluminescence, and magnetism was fabricated by electrospinning.

Novel Electrospun Dual-Layered Composite Nanofibrous Membrane Endowed with Electricity-Magnetism Bifunctionality at One Layer and Photoluminescence at the Other Layer

Dual-layered composite nanofibrous membrane equipped with electrical conduction, magnetism and photoluminescence trifunctionality is constructed via electrospinning. The composite membrane consists of a polyaniline (PANI)/Fe₃O₄ nanoparticles (NPs)/polyacrylonitrile (PAN) tuned electrical-magnetic bifunctional nanofibrous layer at one side and a Eu(TTA)₃(TPPO)₂/polyvinylpyrrolidone (PVP) photoluminescent nanofibrous layer at the other side, and the two layers are tightly combined face-to-face together into the novel dual-layered composite membrane with trifunctionality. The electric conductivity and magnetism of electrical-magnetic bifunctionality can be respectively tunable via modulating the respective PANI and Fe₃O₄ NPs contents, and the highest electric conductivity approaches the order of 1 × 10^-2 S cm^-1. Predominant red emission at 615 nm can be obviously observed in the photoluminescent layer under 366 nm excitation. Moreover, the luminescent intensity of photoluminescent layer is almost unaffected by the electrical-magnetic bifunctional layer because of the fact that the photoluminescent materials have been successfully isolated from dark-colored PANI and Fe₃O₄ NPs. The novel dual-layered composite nanofibrous membrane with trifunctionality has potentials in many fields. Furthermore, the design philosophy and fabrication method for the dual-layered multifunctional membrane provide a new and facile strategy toward other membranes with multifunctionality.

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy3+,Tb3+,Eu3+ phosphors

GdF₃:RE³⁺ (RE = Dy³⁺, Tb³⁺, Eu³⁺) phosphors can realize multicolor emission including white light. Simultaneously, GdF₃:RE³⁺ (RE = Dy³⁺, Tb³⁺, Eu³⁺) phosphors also exhibit paramagnetic properties at room temperature and low temperatures.

NaGdF4:Dy3+ nanofibers and nanobelts: facile construction technique, structure and bifunctionality of luminescence and enhanced paramagnetic performances

NaGdF₄:Dy³⁺ nanofibers and nanobelts with excellent luminescence-magnetic bi-functionality were fabricated via a combination of electrospinning and calcination with fluorination technology.

Dual-mode, tunable color, enhanced upconversion luminescence and magnetism of multifunctional BaGdF5:Ln3+ (Ln = Yb/Er/Eu) nanophosphors

BaGdF₅:Yb³⁺,Er³⁺/Eu³⁺ nanophosphors were prepared by a hydrothermal method, and the energy transfer, color-tunable dual-mode emissions and magnetic properties were studied, which could have promising applications in the fields of LEDs, MRI, biolabels, and so on.

BaGdF5:Dy3+,Tb3+,Eu3+ multifunctional nanospheres: paramagnetic, luminescence, energy transfer, and tunable color

The photoluminescence emission color tones of BaGdF₅:Dy³⁺,Tb³⁺,Eu³⁺ nanomaterials change from yellow-green to red by adjusting the doping concentration and the different excitation wavelengths. Furthermore, the obtained samples also exhibit paramagnetic properties.

Magnetic-downconversion luminescent bifunctional BaGdF5:Dy3+,Eu3+ nanospheres: energy transfer, multicolor luminescence and paramagnetic properties

The color-tunable and white light emissions have been obtained in Dy³⁺ and Eu³⁺ co-activated BaGdF₅ phosphors by adopting different excitation wavelengths. Simultaneously, the obtained samples also exhibit paramagnetic properties at room temperature and low temperature.