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Fracto-mechanoluminescence in Mn/Cu doped ZnS induced by steel ball and cylindrical piston
摘要： Herein, we present a comparison of fracto-mechanoluminescence (FML) from ZnS: Mn and ZnS:Cu phosphors prepared by solid state reaction (SSR) route. The FML emitted by two phosphors was compared in terms of its dependence on time and velocity. The FML intensity initially increases with time attains a peak value followed by decrease at still longer times. Peak ML intensities in both the cases are found to linearly increase with impact velocity and total ML intensity linearly increases with mass of the phosphor samples. ML and photoluminescence (PL) spectra of ZnS: Mn and ZnS: Cu phosphors are recorded to lie at 540 nm and 580 nm, respectively.
关键词： Sensor,ZnS: Cu,ZnS: Mn,Mechanoluminescence,Phosphors
更新于2025-11-21 11:18:25
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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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Luminescence properties in relation to controllable morphologies of Ba <sub/>3</sub> [Ge <sub/>2</sub> B <sub/>7</sub> O <sub/>16</sub> (OH) <sub/>2</sub> ](OH)(H <sub/>2</sub> O):Eu <sup>3+</sup> and its thermal conversion product Ba <sub/>3</sub> Ge <sub/>2</sub> B <sub/>6</sub> O <sub/>16</sub> :Eu <sup>3+</sup>
摘要： Luminescence properties in relation to controllable morphologies of Ba3[Ge2B7O16(OH)2](OH)(H2O):Eu3+ and its thermal conversion product Ba3Ge2B6O16:Eu3+ were investigated. Three types of morphologies of Eu3+-doped Ba3[Ge2B7O16(OH)2](OH)(H2O) phosphors were obtained via hydrothermal reactions by different kinds of raw materials. In addition, Ba3Ge2B6O16:Eu3+ phosphors were obtained by calcining the precursor Ba3[Ge2B7O16(OH)2](OH)(H2O):Eu3+. The structure and morphology of the obtained samples were characterized by XRD, EDS, FT-IR, TG-DTA, SEM and HRTEM. Herein, the effects of the synthesis parameters, including the reaction temperature, boron sources and the dosage, doping of rare earth on the photoluminescence (PL) properties of Ba3[Ge2B7O16(OH)2](OH)(H2O) were investigated in detail. The lifetime and absolute quantum yield (QY) of different morphologies of Ba3[Ge2B7O16(OH)2](OH)(H2O):Eu3+ were also measured. The PL properties of the Ba3Ge2B6O16:Eu3+ phosphor prepared by the precursor calcination method compared with those prepared by the high-temperature solid-state method are discussed.
关键词： Morphologies,Eu3+ doping,Hydrothermal,Borogermanates,Phosphors,Luminescence
更新于2025-11-14 17:04:02
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Luminescence properties of novel Eu <sup>3+</sup> ‐doped tantalate NaCaTiTaO <sub/>6</sub> red‐emitting phosphors for solid‐state lighting
摘要： A novel tantalate red-emitting phosphors NaCa1-xEuxTiTaO6 (x = 0.02-0.50) is synthesized via the traditional solid-state reaction sintering. The photoluminescence properties, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal stability are characterized in detail. Photoluminescence spectra show strong red emission monitored at 614 nm at λex = 395 nm. The spectral properties exhibit excellent color purity, chromaticity coordinate (CIE) characteristics. White light emitting diodes (w-LEDs) device are fabricated by the prepared phosphors and show high quality of color-rendering index. The investigated results suggest that the Eu3+-doped NaCaTiTaO6 phosphors can be as potential substitute red phosphors for w-LEDs.
关键词： Phosphors,Tantalate,NaCaTiTaO6:Eu3+,Luminescence
更新于2025-11-14 15:13:28
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Narrow-Band Green-Emitting Sr <sub/>2</sub> MgAl <sub/>22</sub> O <sub/>36</sub> :Mn <sup>2+</sup> Phosphors with Superior Thermal Stability and Wide Color Gamut for Backlighting Display Applications
摘要： The narrow-band emitting phosphors have been extensively investigated in recent years, with the expectation that a wide color gamut of phosphor-converted backlighting device could be fabricated. Due to the weak electric–phonon interaction and low structural relaxation caused by the high rigid crystal structure and symmetric coordination environment, Sr2MgAl22O36:Mn2+ (SMAO:Mn2+) shows a narrow full-width at half-maximum of 26 nm, a high color purity of 81.5%, and a low thermal quenching (82% at 473 K of the initial intensity at 298 K). Using K2SiF6:Mn4+ as the red phosphor, SMAO:Mn2+ as the green one, and GaN-based chip as the blue component, the white light-emitting diode exhibits a National Television Standard Committee value of 127%. All the results demonstrate that the SMAO:Mn2+ phosphor has a promising application in the field of advanced wide-color-gamut backlight display, and the establishment of the relationships between the narrow-band emission and crystal structure can also be applied to design other novel narrow-band phosphors for backlighting technologies.
关键词： color gamut,inorganic phosphors,narrow-band emission,white light-emitting diodes,Sr2MgAl22O36:Mn2+,thermal stability,backlight displays
更新于2025-09-23 15:23:52
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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
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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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Shock synthesis of Sr2Si5N8:Eu2+ phosphor
摘要： A new approach to synthesise the red-emitting nitridosilicate phosphor Sr2Si5N8:Eu2+ using shock waves is described. The solid state reaction of a mixture of Si3N4, Sr3N2 and EuN was induced using a detonation-driven shock wave apparatus. The obtained products consist of Sr2Si5N8:Eu2+ with a purity of 80–89 %, containing 7–9 % of SrSi7N10 and 4–11 % α-Si3N4, according to Rietveld analyses. Crystallites with sizes of 240–310 nm are formed, yielding particles of 2–3 μm grain size. The luminescence properties are similar to conventionally produced Sr2Si5N8:Eu2+ phosphors.
关键词： High-pressure,Phosphors,Luminescence,Solid state reaction
更新于2025-09-23 15:23:52
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Near-infrared quantum cutting via energy transfer in Bi3+, Yb3+ co-doped Lu2GeO5 down-converting phosphor
摘要： In recent years, down-converting phosphors have grown rapidly and been still growing for their potential to significantly improve the photoelectric conversion efficiency of silicon-based solar cells. However, the discovery of new optical materials with optimized properties (in terms of emission intensity, chemical and thermal stability and quantum yield) would still be of the utmost importance. Herein, we report a novel down-converting phosphor Lu2GeO5: Bi3+, Yb3+. Our research results show that the energy transfer efficiency from Bi3+ to Yb3+ in Lu2GeO5 is as high as 65%. Via such an energy transfer from Bi3+ to Yb3+, an absorbed ultraviolet photon gives rise to almost two emitted infrared photons. The theoretical quantum yield of Lu2GeO5: Bi3+, Yb3+ system is calculated to reach up to 165%. The mechanism of the energy transfer from Bi3+ to Yb3+ is proved to be an electric dipole-dipole interaction. Meanwhile, Lu1.87GeO5: 0.03Bi3+, 0.10 Yb3+ phosphor exhibits an excellent resistance against thermal quenching. The present investigation provides people a new down-converting phosphor Bi3+, Yb3+ co-doped Lu2GeO5 with near-infrared quantum cutting to achieve high photoelectric conversion efficiency of silicon-based solar cells.
关键词： Lu2GeO5: Bi3+, Yb3+,Quantum cutting,Energy transfer,Down-converting phosphors
更新于2025-09-23 15:23:52
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Preparation and Enhancement of Luminescent Intensity of New Rare Earth Molybdate NaLa(MoO4)2:Eu3+ Phosphors
摘要： Novel red-emitting rare earth molybdate phosphors NaLa(MoO4)2:Eu3+ have been successfully synthesized by sol-gel method assisted by microwave. The as-synthesized samples were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction and Fluorescence spectrophotometer, respectively. The results show that the target product NaLa(MoO4)2:Eu3+ have been synthesized by calcining precursor at 800 oC. The obtained samples belong to tetragonal Scheelite-structure and I41/a space group. The excitation spectrum of NaLa(MoO4)2:Eu3+ has a broad band in the range of 250-350 nm and the main peak is at 301 nm. The broad band can be ascribed to the charge transfer band of Mo-O and Eu-O. The sharp lines in 350-500 nm range are due to 4f-4f transitions of Eu3+. The emission spectrum contains a series of narrow peaks, with the main peak at 616 nm originated from the electric dipole transition of 5D0 → 7F2 of Eu3+. The appropriate doping amount of Bi3+ and flux NH4F can enhance luminescent intensity of the sample effectively.
关键词： Rare earth molybdate,Sol-gel method assisted by microwave,Red-emitting phosphors,NaLa(MoO4)2:Eu3+
更新于2025-09-23 15:23:52