- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Tunable photoluminescence properties and energy transfer of Ca5(BO3)3F: Tb3+/Eu3+ phosphors for solid state lighting
摘要： A series of Ca5(BO3)3F: Tb3+/Eu3+ phosphors have been prepared via solid-state reaction. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements. The emission intensity of Ca5(BO3)3F: Tb3+ with Li+, Na+, K+ as charge compensators are remarkably enhanced, and the sample in presence of Na+ exhibits the strongest emission intensity. The emission spectra and fluorescence decays confirm the presence of efficient energy transfers from Tb3+ to Eu3+ in Ca5(BO3)3F: Tb3+/Eu3+ phosphors. The energy transfer mechanism between Tb3+ and Eu3+ has been proven to be resonant type via the electric dipole-dipole interaction. The thermal quenching temperature T50 obtained from the temperature-dependent emission spectra is 478 K, demonstrating a high thermal stability of the as-obtained Ca5(BO3)3F: Tb3+/Eu3+ phosphors. Moreover, by increasing the molar ratio of Eu3+ to Tb3+, the emission colors of Ca5(BO3)3F: Tb3+/Eu3+ phosphors can be tuned from green to orange, and then to red. These results demonstrate that the as-obtained Ca5(BO3)3F: Tb3+/Eu3+ phosphors may have potential applications in solid-state lighting fields.
关键词： Energy transfer,Ca5(BO3)3F,Phosphors,Tunable luminescence,Solid-state reaction
更新于2025-09-23 15:23:52
-
Photoluminescence of partially reduced Eu2+/Eu3+ active centers in a NaF–Al2O3–P2O5 glassy matrix with tunable smooth spectra
摘要： In this work, a series of photoluminescent materials have been synthesized based on optically transparent and chemically stable glasses of the nominal composition Na3Al2(PO4)2F3 (NaF–Al2O3–P2O5 system) doped with 1 wt % of europium. It has been shown that the synthesis conditions (mainly the temperature and duration of the melting stage under reducing conditions) strongly affected the photoluminescence spectra of the material. This effect has been ascribed to varying proportions between Eu3+ and Eu2+ ions concentrations, imposed by the synthesis conditions, which was confirmed by XPS, absorption and decay times measurements. As both Eu3+ and Eu2+ centers exhibit photoluminescence in different ranges of the visible spectra (Eu3+ – red, and Eu2+ – mainly blue) the possibility, shown by us, to control relative proportions of the oxidation states of europium and consequently to control the photoluminescence spectra, may be advantageous from the viewpoint of potential applications of such materials as novel phosphors for white LEDs with the emission spectra resembling natural light.
关键词： glassy matrix,europium facile reduction,scalable synthesis,tunable luminescence
更新于2025-09-23 15:23:52
-
Fluorescent Platforms Based on Organic Molecules for Chemical and Biological Detection
摘要： Fluorescent platforms based on organic molecules have attracted great attention in the field of chemical and biological detection because of their high detection efficiency and sensitivity. Strategies in fluorescent platform design with controlled luminescence properties based on F?rster resonance energy transfer, excimer/exciplex formation, and metal-enhanced fluorescence mechanisms are reviewed herein. Attention is focused on the photophysical processes of fluorescent molecules in their interactions with other components as well as with the target. Color- and intensity-tunable luminescence from energy or electron transfer and the electronic structures of fluorescent molecules are discussed. On the basis of the photophysical properties of fluorescent molecules, their responsive fluorescence signals, which reflect specific inter- and intra-molecular interactions, are particularly effective for chemical and biological detection.
关键词： detection,fluorescent platform,fluorescent molecules,photophysical property,tunable luminescence
更新于2025-09-23 15:21:01
-
Nanocrystalline structure control and tunable luminescent mechanism of Eu-doped CsPbBr3 quantum dots glass for WLED
摘要： As CsPbX3(Cl, Br, I) perovskite quantum dot glass has been widely reported, the discovery of next-generation perovskite luminescent materials has been challenged by doping rare earth activators with energy-level transition. In this work, we report a novel Eu-doped quantum dots glass material with tunable luminescence properties. The structure characteristic and tunable luminescent mechanism were investigated by combining X-ray diffraction, X-ray photoelectric spectroscopy, excitation and emission spectra. It is found that Eu ions replaced the lattice of Pb in CsPbBr3 quantum dots and formed CsEuBr3 quantum dots, which result in a blue emission. Meanwhile, a green emission comes from CsPbBr3 quantum dots, and a red emission originally comes from Eu3+ in glass matrix can also be observed by controlling the heat treatment temperature. A light-emitting diode is designed based on the prepared Eu doped quantum dots glass without doping any phosphors, and a warm-light with CCT at 4075k is obtained. The present work provides a new luminescence tunable design principle of europium doped quantum dots glass materials and could bring inspiration to the future exploration of rare earth ion-doped quantum dot glass material in the future.
关键词： WLED,CsEuBr3,tunable luminescence,Eu-doped,CsPbBr3,perovskite quantum dot glass
更新于2025-09-19 17:13:59
-
Cocrystals with tunable luminescence colour self-assembled by a predictable method
摘要： Organic light-emitting materials play an essential role in the field of luminescent materials because they are easily prepared and they have controllable luminescent properties. Here it is shown that intermolecular interactions and luminescent properties of cocrystals can be predicted using the molecular surface electrostatic potential of selected (cid:3)-hole/(cid:2)-hole(cid:2) (cid:2) (cid:2)(cid:3) bonding donor haloperfluorobenzenes and acceptor acenaphthene (AC). Single-crystal X-ray diffraction data reveal that actual bonding patterns in five cocrystals assembled from haloperfluorobenzenes and AC are in accordance with predictable patterns of intermolecular interactions; that is (cid:3)-hole(cid:2) (cid:2) (cid:2)(cid:3) bond is the major interaction in AC–octafluoronaphthalene, AC–1,4-dibromotetrafluorobenzene and AC–1,3,5-tribromo-2,4,6-trifluorobenzene cocrystals, whereas (cid:2)-hole(cid:2) (cid:2) (cid:2)(cid:3) bond is the major interaction in AC–1,4-diiodotetrafluorobenzene and AC–1,3,5-trifluoro-2,4,6-triiodobenzene cocrystals. The luminescent properties of the cocrystals are affected by the bonding patterns between AC and haloperfluorobenzenes; the (cid:3)-hole(cid:2) (cid:2) (cid:2)(cid:3) bond leads to weak phosphorescence, whereas the (cid:2)-hole(cid:2) (cid:2) (cid:2)(cid:3) bond results in weak delayed fluorescence and relatively strong phosphorescence.
关键词： (cid:2)-hole,predictable,cocrystal,(cid:3)-hole bond,tunable luminescence colour,halogen bond
更新于2025-09-11 14:15:04