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The red persistent luminescence of (Sr,Ca)AlSiN3:Eu2+ and mechanism different to SrAl2O4:Eu2+,Dy3+
摘要： (Sr,Ca)AlSiN3:Eu2+ phosphors have been widely used in phosphor-converted white light emitting diodes. Herein, we reported the strong red persistent luminescence in (Sr,Ca)AlSiN3:Eu2+ under UV light excitation. The Sr0.8Ca0.2AlSiN3:0.15% Eu2+ shows the strongest red persistent luminescence with a peak emission wavelength at ~628 nm and a persistent time of ~9600 s at the 0.32 mcd/m2 threshold value. A new persistent luminescence mechanism, which is different to that of SrAl2O4:Eu2+,Dy3+, was proposed by comparing the thermoluminescence excitation spectrum (TLES) and the photoluminescence excitation spectrum (PLES) of Sr0.8Ca0.2AlSiN3:0.15% Eu2+. The electrons are directly excited from 4f ground states to the conduction band or from valence band to conduction band in (Sr,Ca)AlSiN3:Eu2+; while, in SrAl2O4:Eu2+,Dy3+, they are first excited to 5d level and then stimulated thermal process to the conduction band. The effect of Eu2+ concentration on red persistent luminescence in (Sr,Ca)AlSiN3:Eu2+ were discussed. The proposed mechanism of persistent luminescence can help us to design and find new persistent luminescence materials.
关键词： Persistent luminescence,SrAl2O4:Eu,Dy,Red emission,(Sr,Ca)AlSiN3:Eu,Persistent luminescence mechanism
更新于2025-09-23 15:23:52
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Low-temperature red long-persistent luminescence of Pr3+ doped NaNbO3 with a perovskite structure
摘要： Long persistent luminescence (LPL) phosphors can keep emitting light after the removal of excitation sources under thermal disturbances at room temperature, which provides a wide application from emergency signs to in vivo biological imaging. Unfortunately, these phosphors will exhibit poor LPL performance once the thermal activation energy is not sufficient to release the captured carriers from the traps at low-temperature. Herein, a red phosphor of Pr3+ doped NaNbO3 with a perovskite structure is designed, which realizes a low-temperature LPL. The red emission (λem=612 nm) is ascribed to the 1D2→3H4 transition of Pr3+ ions, and LPL can be visually recognized over 16 hours after the removal of the excitation source at 200 K. Low-temperature thermoluminescence curves, temperature-dependent photoluminescence spectra indicate that abundant traps (≤ 0.6 eV) exist in NaNbO3: Pr3+, which is critical for ensuring the low-temperature LPL. The investigation on low-temperature LPL properties of NaNbO3: Pr3+ helps us to reveal the importance of defects structure, and provides new opportunities in exploring luminescence materials applied in an extreme conditions.
关键词： low-temperature,persistent luminescence,defects structure,phosphors
更新于2025-09-23 15:23:52
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Zn <sub/>3</sub> Ga <sub/>2</sub> Ge <sub/>2</sub> O <sub/>10</sub> :Cr <sup>3+</sup> Uniform Microspheres: Template-Free Synthesis, Tunable Bandgap/Trap Depth, and <i>In Vivo</i> Rechargeable Near-Infrared-Persistent Luminescence
摘要： Near-infrared (NIR) emitting persistent phosphors of Cr3+-doped zinc gallogermanate have emerged for in vivo bio-imaging with the advantages of no need for in situ excitation. However, it is challenging to synthesize well-dispersed and uniform spherical particles with high brightness, high resolution, and distinguished NIR long afterglow. In this work, Zn3Ga2Ge2O10:Cr3+ (ZGGC) monospheres were directly synthesized by a facile hydrothermal method with the assistance of citric anions (Cit3-), which emit a NIR emission at ~696 nm and exhibit excellent NIR persistent luminescence with rechargeability. Controlled experiments indicated that the shape evolution of ZGGC product is significantly affected by Cit3-, solution pH, and the duration and temperature of hydrothermal reaction. Furthermore, compositional influence on the crystal structure, bandgap, trap depth, and luminescence characteristics of ZnyGa2Ge2O10-δ:Cr3+ (y = 2.8, 3.0, 3.2) were investigated in details, which allows to construct an energy level diagram of the ZGGC host, Cr3+ ions, and electron traps. It was found that the bandgap and conduction-band minimum (CBM) are significantly affected by the Zn content, while the valence-band maximum (VBM) is not. The y = 3.0 sample exhibited the best persistent luminescence, owing to its deepest defects. The ZGGC-NH2 prepared through surface functionalization of ZGGC spheres showed distinguished NIR long afterglow, low toxicity, and great potential for in vitro cell imaging and in vivo bio-imaging in the absence of excitation. Moreover, the persistent-luminescence signal from the ZGGC-NH2 can be repeated in vivo through in situ recharge with external excitation of a red LED lamp, indicating that the ZGGC-NH2 is suitable for applications in long-term in vivo imaging.
关键词： in vivo imaging,Near infrared persistent luminescence,conduction band minimum,monospheres
更新于2025-09-23 15:23:52
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Multicolor Persistent Luminescence Realized by Persistent Color Conversion
摘要： Spectral tuning is important for the development of persistent phosphors. Here we introduce a color conversion concept to obtain abundant persistent luminescence spectra in addition to existing methods of exploring new matrix and/or dopants. In this study, CaAl2O4:Eu,Nd was chosen as a blue persistent donor phosphor, while Lu3Al5O12:Ce and other four commercial phosphors were explored as conversion phosphors to obtain colorful persistent luminescence spectra. Both the persistent donor phosphor and conversion phosphors were embedded into resin, forming ternary composite chips to ensure efficient energy transfer. Continuous color tuning were realized by simply changing the mass ratio of the persistent donor phosphor vs. conversion phosphor. Our work will be significant in indicating other persistent/conversion composite materials or nanostructures with abundant spectral properties.
关键词： composite,Persistent luminescence,afterglow,persistent phosphor,spectral tuning
更新于2025-09-23 15:21:01
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Full-color persistent luminescence tuning: A marriage of perovskite quantum dots and lanthanide ions
摘要： In modern society, luminescent materials capable of emitting various colored lights are critically important for lighting and display systems. As a typical kind of luminescent materials, the persistent luminescence phosphors have been widely investigated as night-light vision materials due to their many significant applications such as emergency route signage and security signals, bio-labels, photocatalysts, anti-counterfeiting, optical sensors, and optical data storage. However, realizing multicolored persistent luminescence phosphors has been a long-standing challenge, thus posing a serious problem in their practical applications. In a recent publication in Angewandte Chemie International Edition, Prof. Xueyuan Chen and co-workers demonstrated a simple but effective approach to fine-tuning the persistent luminescence colors, based upon the composites of lanthanide ions doped CaAl2O4:Eu2+,Nd3+ (CAO) blue persistent phosphors with all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite quantum dots (PeQDs). With the help of the radiative energy transfer from CAO blue persistent phosphors to CsPbX3 PeQDs, the persistent luminescence colors can be precisely controlled through tailoring of the PeQDs bandgap. The approach allowed access to full-spectrum persistent luminescence with wavelengths covering the entire visible spectral range by single-wavelength excitation, thus offering new opportunities for persistent luminescence materials in many important emerging applications.
关键词： persistent luminescence,lanthanide ions,full-color tuning,perovskite quantum dots
更新于2025-09-16 10:30:52
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Photostimulated and persistent luminescence of samarium ions in BaFCl
摘要： Storage phosphors with e?cient photostimulated luminescence (PSL) and/or persistent luminescence (PersL) are in great demand for a range of applications. In this paper, PSL, PersL and thermoluminescence (TL) of samarium ions doped in a macroscopic and sub-micron crystals of BaFCl are reported, and it is demonstrated that the co-precipitated BaFCl:Sm3+ sub-micron crystals become an e?cient photostimulable X-ray storage phosphor upon annealing in the temperature range of 200–500 °C. The dependence of storage phosphor properties on annealing temperature was investigated and it was found that the X-irradiated co-precipitated BaFCl:Sm3+ crystallites (~400 nm size) showed maximum PSL and PersL from both Sm2+ and Sm3+ ions when annealed at 500 °C for 4 h. From a comparison with data for the macroscopic crystal (~3 mm) and ball-milled nanopowders (~30 nm), it also followed that PSL and PersL in the BaFCl:Sm system is a?ected by the crystal size. TL from Sm2+ of the macroscopic crystal is compared with the TL of sub-micron powders annealed at di?erent temperatures.
关键词： Storage phosphor,Photostimulated luminescence,Samarium,Thermoluminescence,Persistent luminescence
更新于2025-09-10 09:29:36
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Chromium-Doped Zinc Gallogermanate@Zeolitic Imidazolate Framework-8: A Multifunctional Nanoplatform for Rechargeable In Vivo Persistent Luminescence Imaging and pH-Responsive Drug Release
摘要： Multifunctional theranostic nanoplatforms greatly improve the accuracy and effectiveness in tumor treatments. Much effort has been made in developing advanced optical-imaging-based tumor theranostic nanoplatforms. However, autofluorescence and irradiation damage of the conventional fluorescence imaging technologies as well as unsatisfied curative effects of the nanoplatforms remain great challenges against their wide applications. Herein, we constructed a novel core-shell multifunctional nanoplatform, i.e. chromium-doped zinc gallogermanate (ZGGO) near-infrared (NIR) persistent luminescent nanoparticles (PLNPs) as a core and zeolitic imidazolate framework-8 (ZIF-8) as a shell (namely ZGGO@ZIF-8). The ZGGO@ZIF-8 nanoplatform possessed dual functionalities of the autofluorescence-free NIR PersL imaging as well as the pH-responsive drug delivery, thus was highly expected in tumor theranostics. Notably, the loading content of doxorubicin (DOX) in ZGGO@ZIF-8 (?LC = 93.2%) was quite high, and the drug release of DOX-loaded ZGGO@ZIF-8 was accelerated in an acidic microenvironment such as tumor cells. The ZGGO@ZIF-8 opens up a new material system in the combination of PLNPs with metal–organic frameworks (MOFs) and may offer new opportunities for the development of advanced multifunctional nanoplatforms for tumor theranostics, chemical sensing, and optical information storage.
关键词： persistent luminescence imaging,metal–organic frameworks,core-shell nanostructure,pH-responsive drug delivery,tumor theranostics
更新于2025-09-04 15:30:14