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Tunable magnetic and fluorescent properties of Tb3Ga5O12 nanoparticles doped with Er3+, Yb3+, and Sc3+
摘要： In this study, we present the synthesis of Tb3Ga5O12 nanoparticles doped with Er3+, Yb3+, and Sc3+ ions, prepared using a co-precipitation method. These materials have well-defined magnetic-fluorescence properties. The effects of Yb3+ ion concentration on the structural characteristics, morphology, luminescence, and magnetic properties of the nanoparticles were investigated in detail using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, photoluminescence spectroscopy, and vibrating sample magnetometer measurements. Under 980-nm laser diode excitation, the nanoparticles displayed bright up-conversion luminescence, showing evidence of resonant energy transfer from the Yb3+ to Er3+ ions. Intense green and red emissions located at approximately 526, 548, and 656 nm were attributed to the radiant transitions of 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 of Er3+, respectively. These observations indicate that Tb3Ga5O12:Er3+, Yb3+, Sc3+ magnetic–fluorescent bifunctional nanoparticles are promising materials for use in bioimaging and magnetic bio-separation applications.
关键词： magnetic properties,lanthanide-doped materials,nanoparticles,rare-earth metal,terbium gallium garnet (Tb3Ga5O12),up-conversion luminescence
更新于2025-11-14 15:26:12
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Erbium-to-dysprosium energy-transfer mechanism and visible luminescence in lead-cadmium-fluorogermanate glass excited at 405?nm
摘要： Erbium-to-dysprosium energy-transfer and visible luminescence in the blue, green, yellow, red, and NIR is reported in PbGeO3:PbF2:CdF2 glass under 405 nm excitation. Absorption and excitation spectra were examined in the UV-VIS-IR spectral region. Emission showed a decrease in the Er3+ emissions around 520 and 545 nm when Dy3+ was added to the host matrix, while the Dy3+ emission around 576 nm (4F9/2 – 6H13/2) increased concomitantly. The recorded lifetime for Er3+ emissions also decreased, as Dy3+ concentration was increased for fixed Er3+ content. No similar behavior was observed when Er3+ concentration varied, confirming a one-way Er3+-to-Dy3+ energy transfer mechanism.
关键词： glass,energy-transfer,visible-light,rare-earth
更新于2025-11-14 15:25:21
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Eu and Dy doped borophosphosilicate glass-ceramics for near ultraviolet based light-emitting diode applications
摘要： The Eu and Dy doped borophosphosilicate glass-ceramics prepared using melt quenching technique are investigated for light-emitting diode applications. The X-ray diffraction results show that the precipitation of AlPO4 crystals in glass matrix occurred during the melt quenching process, leading to the formation of glass-ceramics. The content of AlPO4 crystals depends on the B2O3/P2O5 relative content in glass matrix composition. The spontaneous conversion of Eu3+ to Eu2+ takes place in the as-obtained glass-ceramics without using reducing atmosphere during the preparation process. The conversion extent of Eu3+ to Eu2+, optical properties and structure of the as-obtained materials are related to the B2O3/P2O5 relative content. The Eu/Dy co-doped borophosphosilicate glass-ceramics display the emission bands in the blue, yellow, and red light regions and their combinations generate near white light-emission. In addition, the tunable light emission can be realized by changing the concentration of Eu and B2O3/P2O5 relative content. The as-developed Eu and Dy doped borophosphosilicate glass-ceramics show promising prospects in light-emitting diode applications.
关键词： Rare earth,Luminescence,Light-emitting diode,Borophosphosilicate glass-ceramics
更新于2025-11-14 15:23:50
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Highly efficient transparent nanophosphor films for tunable white light-emitting layered coatings
摘要： Bright luminescence in rare-earth (RE) nanocrystals, so-called nanophosphors, is generally achieved by choosing a host that enable the 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 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 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. Total extinction of incoming radiation along with the high quantum yields achieved make these thin layered phosphors one of the most efficient transparent white converter coatings ever developed.
关键词： rare-earth nanocrystals,transparent coatings,nanophosphors,phosphor materials,white-light emission
更新于2025-11-14 15:23:50
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Theoretical Investigation of Thermal Effects in High Power Er <sup>3+</sup> /Yb <sup>3+</sup> - Codoped Double-Clad Fiber Amplifiers for Space Applications
摘要： In this paper, a multiphysics numerical model based on the spatial-dependent rate equations and 3-D non-homogeneous heat conduction model is used to investigate the performance of Er3t/Yb3t-codoped double-clad fiber amplifiers with respect to the constraints associated with space applications. The effects of fiber length, coating thickness, and core radius changes are analyzed. Furthermore, the impact of thermal heating due to the high power optical signals propagating along the fiber on the amplifier gain is examined. The temperature dependence of the refractive index, emission and absorption cross sections, as well as the radiation induced attenuation is derived and modeled. It is observed that the coating thickness affects the temperature distribution along the whole fiber length. Thicker coating mitigates the temperature variation along the fiber as well as it improves the temperature difference between the core center and the outer fiber surface. Moreover, larger core results in higher optical gain and shorter fibers. By numerical results, it is inferred that the thermal effects could strongly degrade the whole amplifier performance.
关键词： heat conduction,rare earth,fiber amplifier,thermal analysis
更新于2025-09-23 15:23:52
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A highly efficient fluorescent material based on rare-earth-modified polyhydroxyalkanoates
摘要： Fluorescent materials play an important role in biomedical fields. However, the main types of fluorescent materials suffer from several disadvantages especially the biotoxicity, which largely restrict its wider applications in biological fields. In this study, a highly efficient rare-earth-modified fluorescent material was successfully designed and fabricated based on polyhydroxyalkanoates, which are known as biodegradable and biocompatible material. A new Functional-PHA polymer was microbially synthesized by engineered Halomonas bluephagenesis and was used as a basal matrix to generate the rare-earth-modified PHA. N-acetyl-L-cysteine-grafted PHA (NAL-grafted-PHA) was first produced via a UV-initiated thiol-ene click reaction and the rare earth metal ions (Eu3+ and Tb3+) were subsequently chelated onto the NAL-grafted-PHA through the coordination effect. The composite material exhibited intense photoluminescence properties under UV laser excitation, indicating the excellent features as fluorescent material. The enhanced hydrophilicity and superior biocompatibility of rare earth-chelated PHA were confirmed, suggesting its great potential application value in biomedical fields.
关键词： Halomonas,photoluminescence,next generation industrial biotechnology,fluorescent material,polyhydroxyalkanoates,PHB,Rare-earth metal ions
更新于2025-09-23 15:23:52
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Non-Invasive Optical Guided Tumor Metastasis/Vessel Imaging by Using Lanthanide Nanoprobe with Enhanced Down-Shifting Emission beyond 1500 nm
摘要： Visualization of tumor vessels/metastasis and cerebrovascular architecture is vital important for analyzing pathological states of brain diseases and tumor's abnormal blood vessel to improve cancer diagnosis. In vivo fluorescence imaging using second near infrared emission beyond 1500 nm (NIR-IIb) is emerged as a next generation optical imaging method with significant improvement in imaging sensitivity and spatial resolution. Unfortunately, highly biocompatible probe capable of generating NIR-IIb emission with sufficient brightness and uniformed size is still scarce. Here, we have proposed the polyacrylic acid (PAA)-modified NaLnF4:40Gd/20Yb/2Er nanorods (Ln=Y, Yb, Lu, PAA-Ln-NRs) with enhanced downshifting NIR-IIb emission, high quantum yield (QY), relative narrow bandwidth (~160 nm) and high bio-compatibility via Ce3+ doping for high performance NIR-IIb bioimaging. The downshifting emission beyond 1500 nm is improved by 1.75~2.2 times with simultaneously suppressing the upconversion (UC) path in Y, Yb, and Lu hosts via Ce3+ doping. Moreover, compared with the traditionally used Y-based host, the QY of NIR-IIb emission in Lu-based probe in water is improved from 2.2% to 3.6%. The explored bright NIR-IIb emitted PAA-Lu-NRs were used for high sensitivity small tumor (~ 4 mm)/metastatic tiny tumor detection (~ 3 mm), tumor vessel visualization with high spatial resolution (41 μm) and brain vessel imaging. Therefore, our findings open up the opportunity of utilizing lanthanide based NIR-IIb probe with bright 1525 nm emission for in vivo optical-guided tumor vessel/metastasis and non-invasive brain vascular imaging.
关键词： enhancement of downshifting emission,tiny metastatic tumor detection,tumor vascular imaging,rare-earth nanoprobes,brain vascular imaging
更新于2025-09-23 15:23:52
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Optical, magnetic and ferroelectric properties of Ba0.2Cu0.8-xLaxFe2O4 (x?=?0.2–0.6) nanoparticles
摘要： The Ba0.2Cu0.8-xLaxFe2O4 (x = 0.2, 0.4 & 0.6) (BCLF) nanoparticles were prepared by hydrothermal method and further characterized for structural, morphological, optical, magnetic, and ferroelectric properties. The structural analysis was carried out using X-ray diffraction spectra. These results revealed that all the samples showed the presence of cubic spinel phases. The Fourier transform infrared (FTIR) studies expressed the formation of broad (ν1) and narrow (ν2) absorption bands which can reflect the arrangement of cations between tetrahedral (ν1) and octahedral (ν2) sites. The surface morphology was studied using the field emission scanning and transmission electron microscopes (FESEM & TEM). The FESEM pictures expressed the gradual formation of nanofibers with increase of La-content. The variation of optical bandgap (Eg~1.96–2.15 eV) as a function of substituent concentration was elucidated. The magnetization versus applied magnetic field (M–H) loops of BCLF nanoparticles showed the superparamagnetic nature which can be useful for the biomedical applications. The cation distribution was made between the octahedral (B) and tetrahedral (A) sites using the Neel's two-sublattice model.
关键词： Nanoparticles,Structure,Optical properties,Rare Earth,Magnetic properties
更新于2025-09-23 15:23:52
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Excellent photoluminescence and temperature sensing properties in Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics
摘要： Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics were prepared by a high temperature solid-state reaction method. SEM observation confirms that there are no obvious impurities or pores existed in the grain boundaries of the samples. Accordingly, all the samples show excellent transparency in the visible and near-infrared range. Upon 980 nm excitation, strong green emission peaked at 549 nm, red emissions centered at 667 and 756 nm, as well as near infrared emission located at 2 μm respectively from Ho3+ ions are observed. By utilizing the fluorescence intensity ratio (FIR) technique, the temperature sensing behaviors of the optimal sample (Yb0.03Ho0.01Y0.84La0.09Zr0.03)2O3 are investigated at different excitation power densities based on the non-thermally coupled levels of 5F4/5S2 and 5F5. The thermometry is found to be immune to the excitation power density, leading to the consistent calibration curves and sensing sensitivities at the different power densities. The maximal sensing sensitivity is about 71.28×10?4 K?1 at 563 K. The results indicate that the Ho3+/Yb3+ codoped (Y0.88La0.09Zr0.03)2O3 transparent ceramics are promising for the temperature sensors, display devices and 2 μm solid-state lasers.
关键词： Upconversion luminescence,Rare earth,Optical thermometry,Transparent ceramics
更新于2025-09-23 15:23:52
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Polysiloxane-based Hyperbranched Fluorescent Materials Prepared by Thiol-ene “Click” Chemistry as Potential Cellular Imaging Polymers
摘要： Hyperbranched polymers have attracted increasing interest due to their unique properties which possess excellent RI and thermal stability, and have been widely used in fields of drug delivery, catalysts, liquid crystal and so on. Herein, polysiloxane-based hyperbranched fluorescent materials (P1 and P2) were synthesized by thiol-ene “click” chemistry. Then, novel polysiloxane-based hyperbranched fluorescent materials (P1-Ln3+) has been prepared by rare earth ions coordination. In view of the splendid fluorescence characteristics and favorable stability of P1-Ln3+, it has been applied in biological imaging. P1-Ln3+ has gained commendable applications in bioimaging.
关键词： Fluorescence materials,Living cells imaging,Hyperbranched polymers,Thiol-ene "click" chemistry,Coordination,Rare earth ions
更新于2025-09-23 15:23:52