Browse
Submit Data
Databases
API
Help

Dataset Information

18 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A Guide to Brighter Phosphors-Linking Luminescence Properties to Doping Homogeneity Probed by NMR.

ABSTRACT: Crystalline powders of Ln3+ doped LaPO4 (Ln=Nd, Gd, Dy, Ho, Er, Tm, Yb) have been synthesized to serve in a case study for linking doping homogeneity as determined by NMR to luminescent properties. Samples obtained via different synthesis methods act as examples of homo- and inhomogeneous doping. The sample quality was verified by X-ray diffraction. The homogeneously doped samples show improved luminescent properties in terms of brightness and lifetime which is consistent with the interpretation that, NMR visibility curves probe the distribution of paramagnetic dopants on a similar length scale as necessary for an efficient energy transfer in crystalline phosphors i.?e. between sensitizers and activators, and to killer sites. Thus "NMR homogeneity" as observed by visibility curves may serve as a tool to optimize luminescent materials.

SUBMITTER: Li W

PROVIDER: S-EPMC6916297 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A Guide to Brighter Phosphors-Linking Luminescence Properties to Doping Homogeneity Probed by NMR.

Li Wenyu W Adlung Matthias M Zhang Qianyun Q Wickleder Claudia C Schmedt Auf der Günne Jörn J

Chemphyschem : a European journal of chemical physics and physical chemistry 20191107 23

Crystalline powders of Ln<sup>3+</sup> doped LaPO<sub>4</sub> (Ln=Nd, Gd, Dy, Ho, Er, Tm, Yb) have been synthesized to serve in a case study for linking doping homogeneity as determined by NMR to luminescent properties. Samples obtained via different synthesis methods act as examples of homo- and inhomogeneous doping. The sample quality was verified by X-ray diffraction. The homogeneously doped samples show improved luminescent properties in terms of brightness and lifetime which is consistent w ...[more]

PMID: 31589801

Similar Datasets

Electrical stimulation for brighter persistent luminescence.

Project description:An immature understanding of the mechanisms of persistent luminescence (PersL) has hindered the development of new persistent luminescent materials (PersLMs) with increased brightness. In this regard, in-situ direct current (DC) electric field measurements were conducted on a layered structure composed of the SrAl2O4:Eu2+,Dy3+ phosphor, and an electrode. In this study, the photoluminescence (PL) and afterglow properties were investigated with respect to voltage by analyzing the current signal and thermoluminescence (TL) spectroscopy. The intensity of PersL increased due to a novel phenomenon known as "external electric field stimulated enhancement of initial brightness of afterglow". This dynamic process was illustrated via the use of a rate equation approach, where the electrons trapped by the ultra-shallow trap at 0.022 eV could be transferred through the conduction band during long afterglow. The afterglow intensity could reach 0.538 cd m-2 at a 6 V electric voltage. The design of an electric field stimulation technique enables the enhancement of the intensity of PersLMs and provides a new perspective for exploring the fundamental mechanics of certain established PersLMs.

| S-EPMC11251151 | biostudies-literature

Solar-blind ultraviolet-C persistent luminescence phosphors.

Project description:Visible-light and infrared-light persistent phosphors are extensively studied and are being used as self-sustained glowing tags in darkness. In contrast, persistent phosphors for higher-energy, solar-blind ultraviolet-C wavelengths (200-280?nm) are lacking. Also, persistent tags working in bright environments are not available. Here we report five types of Pr3+-doped silicates (melilite, cyclosilicate, silicate garnet, oxyorthosilicate, and orthosilicate) ultraviolet-C persistent phosphors that can act as self-sustained glowing tags in bright environments. These ultraviolet-C persistent phosphors can be effectively charged by a standard 254?nm lamp and emit intense, long-lasting afterglow at 265-270?nm, which can be clearly monitored and imaged by a corona camera in daylight and room light. Besides thermal-stimulation, in bright environments, photo-stimulation also contributes to the afterglow emission and its contribution can be dominant when ambient light is strong. This study expands persistent luminescence research to the ultraviolet-C wavelengths and brings persistent luminescence applications to light.

| S-EPMC7184723 | biostudies-literature

Preparation and Luminescence Properties of Ba₅Si₈O21 Long Persistent Phosphors Doped with Rare-Earth Elements.

Project description:The phosphors of formula Ba₅Si₈O21:Eu2+,Dy3+ were synthesized and studied in order to improve their properties. Their synthesis conditions were evaluated as a function of precursors, crucible composition, flux agents, dopants and temperatures. The samples were characterised by means of a systematic investigation through elemental, kinetic, mineralogical (both qualitative and quantitative), and morphological analysis. This study allows for a careful evaluation of the parameters that influence the formation and properties of Ba₅Si₈O21:Eu2+,Dy3+ phosphors. As for the synthesis conditions, the use of Na₂SiO₃, BaCO₃ and NH₄Cl as precursors was very important to reduce the temperature and time of synthesis. The reducing atmosphere produced with purified coal was cheaper and gave results similar to the more traditional gas mixture (H₂/N₂). At the end of this study, a phosphor with improved long persistent phosphorescence (LPP) characteristics was obtained with Ba/Si = 0.7, Eu/Si = 2.8 × 10-3 and Dy/Si = 3.6 × 10-3 following a 6 h-synthesis in a quartz crucible.

| S-EPMC6337357 | biostudies-literature

Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu(3+) phosphors and ceramics.

Project description:A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu(3+) phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu(3+) showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu(3+) doped phosphors possess stable emission up to 400?K and lose half of the efficiency only at 515?K. In addition, ceramic disks of Y2Mo4O15:75%Eu(3+) phosphor with thickness of 0.71 and 0.98?mm were prepared and it turned out that they efficiently convert radiation of 375 and 400?nm LEDs to the red light, whereas combination with 455?nm LED yields purple colour.

| S-EPMC4867634 | biostudies-literature

Enhanced Luminescence of Long-Wavelength Broadband Near-Infrared Germanate Phosphors.

Project description:Long-wavelength broadband near-infrared (NIR) phosphors have attracted considerable interest in the fields of medical cosmetology and organic detection because of their special emission band. Herein, Ca2GeO4(CGO): Cr4+ NIR phosphor, presenting a broadband emission with longer wavelength ranging from 1100 to 1600 nm, has been synthesized. Further, the luminescence intensity and quantum efficiency of Cr4+ could be obviously improved via the energy transfer from Eu3+ to Cr4+. The energy transfer is dominated by the dipole-dipole mechanism, which can be inferred from the spectra and the decay curves. Furthermore, in order to evaluate the potential application, an NIR phosphor-converted light-emitting diode (pc-LED) based on blue chip has been prepared. Consequently, CGO: Eu3+, Cr4+ exhibits proper output power and wider half-width than the NIR LED chip, indicating its great prospect for long-wavelength NIR pc-LED applications.

| S-EPMC10157857 | biostudies-literature

Tunable Luminescence in Sr2MgSi2O7:Tb3+, Eu3+Phosphors Based on Energy Transfer.

Project description:A series of Tb3+, Eu3+-doped Sr2MgSi2O7 (SMSO) phosphors were synthesized by high temperature solid-state reaction. X-ray diffraction (XRD) patterns, Rietveld refinement, photoluminescence spectra (PL), and luminescence decay curves were utilized to characterize each sample's properties. Intense green emission due to Tb3+ 5D4→7F5 transition was observed in the Tb3+ single-doped SMSO sample, and the corresponding concentration quenching mechanism was demonstrated to be a diople-diople interaction. A wide overlap between Tb3+ emission and Eu3+ excitationspectraresults in energy transfer from Tb3+ to Eu3+. This has been demonstrated by the emission spectra and decay curves of Tb3+ in SMSO:Tb3+, Eu3+ phosphors. Energy transfer mechanism was determined to be a quadrupole-quadrupole interaction. And critical distance of energy transfer from Tb3+ to Eu3+ ions is calculated to be 6.7 Å on the basis of concentration quenching method. Moreover, white light emission was generated via adjusting concentration ratio of Tb3+ and Eu3+ in SMSO:Tb3+, Eu3+ phosphors. All the results indicate that SMSO:Tb3+, Eu3+ is a promising single-component white light emitting phosphor.

| S-EPMC5503325 | biostudies-other

New Insight into Phase Formation of MxMg2Al(4+x)Si(5-x)O18:Eu2+ Solid Solution Phosphors and Its Luminescence Properties.

Project description:Here we reported the phase formation of MxMg2Al(4+x)Si(5-x)O18:Eu(2+) (M = K, Rb) solid solution phosphors, where M(+) ions were introduced into the void channels of Mg2Al4Si5O18 via Al(3+)/Si(4+) substitution to keep the charge balance. XRD results revealed that the as-prepared phosphors with different M(+) contents were iso-structural with Mg2Al4Si5O18 phase. The combined analysis of the Rietveld refinement and high resolution transmission electron microscopy (HRTEM) results proved that M(+) ions were surely introduced into the intrinsic channels in Mg2Al4Si5O18. The emission peaks of MxMg2Al(4+x)Si(5-x)O18:Eu(2+) (M = K, Rb) phosphors with various x values performed a systematic red-shift tendency, which was ascribed to the elongation of [MgO6] octahedra. The temperature stable photoluminescence and internal quantum efficiency (QE) of MxMg2Al(4+x)Si(5-x)O18:Eu(2+) (M = K, Rb) phosphors were enhanced owing to the filling of M(+) in the void channels suggesting a new insight to design the solid solution phosphors with improved photoluminescence properties.

| S-EPMC4507260 | biostudies-literature

Quenching of the red Mn4+ luminescence in Mn4+-doped fluoride LED phosphors.

Project description:Red-emitting Mn4+-doped fluorides are a promising class of materials to improve the color rendering and luminous efficacy of white light-emitting diodes (w-LEDs). For w-LEDs, the luminescence quenching temperature is very important, but surprisingly no systematic research has been conducted to understand the mechanism for thermal quenching in Mn4+-doped fluorides. Furthermore, concentration quenching of the Mn4+ luminescence can be an issue but detailed investigations are lacking. In this work, we study thermal quenching and concentration quenching in Mn4+-doped fluorides by measuring luminescence spectra and decay curves of K2TiF6:Mn4+ between 4 and 600 K and for Mn4+ concentrations from 0.01% to 15.7%. Temperature-dependent measurements on K2TiF6:Mn4+ and other Mn4+-doped phosphors show that quenching occurs through thermally activated crossover between the 4T2 excited state and 4A2 ground state. The quenching temperature can be optimized by designing host lattices in which Mn4+ has a high 4T2 state energy. Concentration-dependent studies reveal that concentration quenching effects are limited in K2TiF6:Mn4+ up to 5% Mn4+. This is important, as high Mn4+ concentrations are required for sufficient absorption of blue LED light in the parity-forbidden Mn4+ d-d transitions. At even higher Mn4+ concentrations (>10%), the quantum efficiency decreases, mostly due to direct energy transfer to quenching sites (defects and impurity ions). Optimization of the synthesis to reduce quenchers is crucial for developing more efficient highly absorbing Mn4+ phosphors. The present systematic study provides detailed insights into temperature and concentration quenching of Mn4+ emission and can be used to realize superior narrow-band red Mn4+ phosphors for w-LEDs.

| S-EPMC6106983 | biostudies-literature

Bright luminescence from pure DNA-curcumin-based phosphors for bio hybrid light-emitting diodes.

Project description:Recently, significant advances have occurred in the development of phosphors for bio hybrid light-emitting diodes (Bio-HLEDs), which have created brighter, metal-free, rare-earth phosphor-free, eco-friendly, and cost-competitive features for visible light emission. Here, we demonstrate an original approach using bioinspired phosphors in Bio-HLEDs based on natural deoxyribonucleic acid (DNA)-curcumin complexes with cetyltrimethylammonium (CTMA) in bio-crystalline form. The curcumin chromophore was bound to the DNA double helix structure as observed using field emission tunnelling electron microscopy (FE-TEM). Efficient luminescence occurred due to tightly bound curcumin chromophore to DNA duplex. Bio-HLED shows low luminous drop rate of 0.0551?s(-1). Moreover, the solid bio-crystals confined the activating bright luminescence with a quantum yield of 62%, thereby overcoming aggregation-induced quenching effect. The results of this study herald the development of commercially viable large-scale hybrid light applications that are environmentally benign.

| S-EPMC5004171 | biostudies-literature

Facile Synthesis of Mn4+-Activated Double Perovskite Germanate Phosphors with Near-Infrared Persistent Luminescence.

Project description:Tetravalent manganese doped phosphors are emerging as a new class of efficient near-infrared emitters for applications in a variety of areas, such as bioimaging and night-vision surveillance. Novel double perovskite-type La2MgGeO6:Mn4+ phosphors were successfully prepared using a microwave-assisted energy-saving solid state method. This simple technique involving the use of a microwave susceptor allows for a reduction of the preparation time compared to a conventional solid state reaction. The samples were investigated using powder X-ray diffraction, scanning electron microscopy, as well as energy-dispersive X-ray spectroscopy mapping, photoluminescence excitation/emission spectroscopy, persistent luminescence decay and temperature-dependent photoluminescence analysis. Substitution between isovalent Mn4+ and Ge4+ can be achieved without additional charge compensators in this germanate-based phosphor, which provides strong emission in the near-infrared spectral region, assigned to the characteristic transitions of tetravalent manganese ions. Additionally, the double perovskite-type germanate phosphor exhibits excellent luminescence thermal stability. Moreover, the spectroscopic properties, excitation wavelength-dependent and temperature-dependent persistent luminescence were studied. A series of thermoluminescence measurements were presented trying to give clear information on the charging process, afterglow behavior and the nature of the traps responsible for the persistent luminescence. The present investigation expands the range of available promising near-infrared emitting persistent phosphors for medical imaging.

| S-EPMC6955683 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data