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1.
LaF3 : Eu3+ nanocrystal/PNIPAM nanogels: Preparation,thermosensitive fluorescence performance and use as bioprobes for monitoring drug release
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Novel core–shell LaF3 : Eu3+ nanocrystals/PNIPAM nanogels were prepared by surface‐initiated living radical polymerization. The microstructure and performance of the LaF3 : Eu3+ nanocrystals and the hybrid nanogels were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD), X‐ray photoelectron spectrometer (XPS), and photoluminescence (PL). The thermosensitive fluorescence behaviors of the core–shell nanogels and the drug release behaviors were investigated by PL at various temperatures. The results suggested that the fluorescence performance of the nanogels was influenced greatly by the ambient temperature, either content of Aspirin absorbed in the nanogels. Compared to other reported systems, our discovery could tell how much the nanogels contain Aspirin by detecting the fluorescence intensity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39930. 相似文献
2.
Synthesis and luminescent properties of Sr4−xSi3O8Cl4: xEu3+ red phosphor by hydrothermal method
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Zhiren Wei Kun Zheng Tengxuan Hou Ruiqi Wang Zhe Wen Boyu Wang Xu Li Li Guan Zhiping Yang Feng Teng 《International Journal of Applied Ceramic Technology》2018,15(1):118-124
Sr4‐xSi3O8Cl4:xEu3+ (SSOC:Eu3+) phosphors were successfully synthesized by hydrothermal method. The crystallization of this phosphor was analyzed by means of X‐ray diffraction patterns. The size and morphology were recorded using SEM patterns of samples. And the PLE and PL spectra were characterized by a PL spectrophotometer. Excited by 394 nm UV light, the intense red emission is recognized in SSOC:Eu3+ phosphor and the main emission peak located at 620 nm. The influences of Eu3+ concentration, pH value of reaction solution, and charge compensator on PL spectra of SSOC:Eu3+ phosphors were investigated. The results revealed that this red phosphor had potential applications for white LEDs. 相似文献
3.
Macgregor Macintosh Qianting Yao Jie Xu Zhaohui Dong Lo-Yueh Chang Lijia Liu 《Ceramics International》2021,47(8):11387-11393
We present a study on the crystal structure and luminescence of Eu3+-doped calcium phosphate (Eu-CaP) nanoparticles. The sintering treatment on the pristine Eu-CaP leads to its crystallization into hydroxyapatite (HA) and further to biphasic structure that contains both HA and β-tricalcium phosphate (β-TCP). Photoluminescence spectroscopy has been a widely used technique to identify the site occupancy of Eu3+ and its thermal-induced migration behavior in pure phase CaP. However, for sintering process that involves the emergence of a second phase or the doped CaP is not luminescent, PL alone is insufficient to characterize how the dopant ions behave during the formation of a biphasic structure. In this work, we utilize X-ray absorption fine structure (XAFS) as an alternative structure probe, targeting the local structure around Eu3+, and track the change in the interatomic distance and coordination number of Eu with its neighboring O, P, and Ca atoms. A model describing formation process of a biphasic structure from HA with the presence of Eu3+ is proposed. 相似文献
4.
Dong Wang Xufeng Guan Guifang Li 《International Journal of Applied Ceramic Technology》2023,20(5):3171-3182
A series of LiCaGd(WO4)3 : xEu3+ (0 ≤ x ≤ 1.0) red phosphors with tetragonal scheelite structure were synthesized via the conventional solid-state reaction. Their crystal structure, photoluminescence excitation (PLE), and photoluminescence (PL) spectra, thermal stability and quantum efficiency were investigated. The phosphors exhibit a typical red light upon 395 nm near ultraviolet excitation, and the strongest emission peak at 617 nm is dominated by the 5D0→7F2 transition of Eu3+ ions. The PL intensity of the phosphors gradually increases with the increase of Eu3+ doping concentration, and the concentration quenching phenomenon is hardly observed. The quantum efficiency and the color purity of the phosphor reach maximum values of about 94.2 and 96.6% at x = 1.0, respectively. More importantly, LiCaGd(WO4)3:xEu3+ phosphors have prominent thermal stability. The temperature-dependent PL intensity of the phosphors at 423 K is only reduced to 89.1% of the PL intensity at 303 K, which is superior to that of commercial red phosphors Y2O3:Eu3+. Finally, LiCaGd(WO4)3:Eu3+ phosphor is packaged with near ultraviolet InGaN chips to fabricate white light emitting diodes, which has a low color temperature (CCT = 4622 K) and a high color rendering index (CRI= 89.6). 相似文献
5.
Effect of Crystallite Size and Crystallinity on Photoluminescence Properties and Energy Transfer of Y6MoO12:Eu
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Huaiyong Li Xipeng Pu Jie Yin Xiaoqin Wang Shujuan Yao Hyeon Mi Noh Jung Hyun Jeong 《Journal of the American Ceramic Society》2016,99(3):954-961
The phosphors Y6MoO12:Eu3+ have been synthesized via citrate complexation method at different calcination temperatures. The evolutions of the crystal structure and the photoluminescence (PL) properties were characterized by means of powder X‐ray diffraction (XRD), Raman and PL spectra, respectively. It was revealed that a red emission could be obtained via three excitation channels, namely f–f transition of Eu3+ ions, charge‐transfer transition from O2 to Eu3+, and interband transition (IBT) of MoO6 groups. The PL spectra and their temporal decay character of Eu3+ ions depended on both crystal structure and excitation channel. The emission reduced with the crystallite size when Eu3+ ions were excited directly, but the emission evolved in a different model with the host lattices were excited. The effect of grain boundary and other lattice defect on the energy transfer and dissipation within the phosphors were discussed. 相似文献
6.
A red long-lasting phosphorescent material, monodisperse Y2O2S: Eu3+, Mg2+, Ti4+ nanospheres have been prepared successfully. Y(OH)(CO3): Eu3+ nanospheres were firstly synthesized via an urea-based homogeneous precipitation technique to serve as the precursor. Nanospheres long-lasting phosphors Y2O2S: Eu3+, Mg2+, Ti4+ were obtained by calcinating the precursor in CS2 atmosphere. XRD investigation shows a pure phase of Y2O2S, indicating no other impurity phase appeared. SEM observation reveals that the structures are nanosphere. The Y2O2S: Eu3+, Mg2+, Ti4+ nanospheres with particle size about 100–150 nm show uniform size and well-dispersed distribution. After irradiation by ultraviolet radiation with 325 nm for 5 min, the phosphor emitted red color long-lasting phosphorescence corresponding to typical emission of Eu3+ ion. The main emission peaks are ascribed to Eu3+ ions transition from 5DJ (J = 0, 1, 2) to 7FJ (J = 0, 1, 2, 3, 4). Both the PL spectra and luminance decay revealed that this phosphor had efficient luminescent and long-lasting properties. It was considered that the red-emitting long-lasting phosphorescence was due to the persistent energy transfer from the traps to the Ti4+ and Mg2+ ions. 相似文献
7.
Riccardo Marin Gabriele Sponchia Enrico Zucchetta Pietro Riello Francesco Enrichi Goffredo De Portu Alvise Benedetti 《Journal of the American Ceramic Society》2013,96(8):2628-2635
In this work, we demonstrate that the martensitic t → m phase transformation of ZrO2 powder stabilized with Eu3+ and Eu3+/Y3+ ions, can be effectively monitored by photoluminescence (PL) spectroscopy. As the luminescent properties of Eu3+ from within a host lattice are strongly influenced by the coordination geometry of the ion, we used the emission spectrum to monitor structural changes of ZrO2. We synthesized Eu3+‐doped and Eu3+/Y3+‐codoped samples via the coprecipitation method, followed by calcination. We promoted the martensitic transformation by applying mechanical compression cycles with an increasing pressure, and deduced the consequential structural changes from the relative intensities of the 5D0 → 7F2 hypersensitive transitions, centered, respectively, at 606 and 613 nm whether the Eu3+ is in the eightfold coordinated site of the tetragonal phase or in the sevenfold coordinated site of the monoclinic phase. We suggest that the unique emission profile for Eu3+ ions in different symmetry sites can be exploited as a simple analytical tool for remote testing of mechanical components that are already mounted and in use. The structural changes observed by PL spectroscopy were corroborated by X‐ray powder diffraction (XRPD), with the phase compositions and volume fractions being determined by Rietveld analysis. 相似文献
8.
Dalai Jin Jingjing Yang Xiang Miao Lina Wang Longcheng Wang 《International Journal of Applied Ceramic Technology》2013,10(4):603-609
YBO3:Eu3+ microspheres were synthesized by a hydrothermal method. Size and surface morphology of the spheres were tailored by ion‐adding. Phase identification, morphology observation, and photoluminescence (PL) performance of the YBO3:Eu3+ microspheres were characterized byX‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), and PL spectrophotometer, respectively. Moderate particles with enlarged size and perfect surface were achieved by adding Li+ ion or/and Mg2+ ion. PL emissions of such YBO3:Eu3+ phosphors were enhanced. Significantly improved PL intensity was achieved when 1% Li+ ion and 5% Mg2+ ion were added, which was nearly doubled compared with the reference sample. 相似文献
9.
Shao-Wen Cao Ying-Jie Zhu Jin Wu Ke-Wei Wang Qi-Li Tang 《Nanoscale research letters》2010,5(4):781-785
The P123/ACP nanocomposite with sizes less than 100 nm consisting of triblock copolymer P123 and amorphous calcium phosphate
(ACP) has been prepared by using an aqueous solution containing CaCl2, (NH4)3PO4, and P123 at room temperature. The P123/ACP nanocomposite is used as the nanocarrier for hydrophobic drug ibuprofen, based
on the combined advantages of both amphiphilic block copolymer and calcium phosphate delivery system. The P123/ACP nanocomposite
has a much higher ibuprofen loading capacity (148 mg/g) than the single-phase calcium phosphate nanostructures. The drug release
percentage of the P123/ACP nanocomposite in simulated body fluid reaches about 100% in a period of 156 h, which is much slower
than that of single-phase calcium phosphate nanostructures. It is expected that the P123/ACP nanocomposite is promising for
the application in the controlled delivery of hydrophobic drugs. 相似文献
10.
Akhil Jain Claudia A.E. González Elias M. Tejeda Alejandro Durán Oscar E. Contreras Gustavo A. Hirata 《Ceramics International》2018,44(2):1886-1893
In this work, YAG:RE3+ (RE = Pr3+, Tm3+, Tb3+, Ce3+, Eu3+, Nd3+, and Er3+;Yb3+) luminescent nanospheres with tunable photoluminescence (PL) emission were prepared by using fast and energy-saving microwave-assisted synthesis (MWAS). The nanopowders were post-annealed at 1100 °C for 3 h to obtain nanocrystalline phosphors. X-ray diffraction (XRD) analysis confirmed the presence of nanocrystals that were well indexed to the cubic YAG phase. Surface chemical groups were detected using Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopy (TEM) showed that the synthesized samples consist of nanospheres with an average size of ~ 110 nm. The effect of aluminum precursors on the morphology of synthesized nanoparticles is discussed. The produced nanophosphors showed strong emission at different wavelengths (ultraviolet, visible and near-infrared) corresponding to different RE3+ ions. Altogether, the merits of spherical morphology and PL emission at various wavelengths endow rare-earth-doped YAG nanoparticles with suitable characteristic for potential applications in the field of nanomedicine (e.g., bioimaging and nanoscintillators), light display systems, optoelectronic devices, and lasers. 相似文献
11.
Jaehan Park Woohyun Jung Young Jin Kim 《Journal of the American Ceramic Society》2017,100(5):2136-2143
Sr2‐xBaxSi(O,N)4:Eu2+ (SBxSON:Eu2+) oxynitridosilicate phosphors were prepared via incorporation of N3?, Eu2+, and Ba2+ ions into Sr2SiO4 (SSO) lattices. X‐ray diffraction patterns of the prepared powders revealed that SBxSON:Eu2+ was a solid‐solution form of SSO. An increase in x values caused a phase transition and an expansion of the unit cell. The photoluminescence excitation (PLE) spectra of SBxSON:Eu2+ were broad, covering the ultraviolet range to the visible range. Corresponding PL emission spectra strongly depended on the excitation wavelengths and consisted of two emission bands, one in the green‐blue region (A‐band) and the other in the red region (B‐band), which were assigned to Eu(I) and Eu(II), respectively. The B‐band resulted from a dramatic red‐shift of the green emission band assigned to Eu(II) of SSO:Eu2+, revealing that the nitridation process preferentially affected the Eu(II) sites. This behavior was explained by crystal field splitting, the fluorescence decay time, and thermal quenching. The Ba2+ substitution caused evolution of the PL spectra, and its effects on the spectra were discussed under consideration of ionic size and covalence. 相似文献
12.
Novel YVO4:Eu3+/YBO3 core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method.
X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures.
Photoluminescence (PL) study reveals that PL efficiency of the YVO4:Eu3+ nanocrystals (cores) can be improved by the growth of YBO3 nanocoatings onto the cores to form the YVO4:Eu3+/YBO3 core/shell heteronanostructures. Furthermore, shell ratio plays a critical role in their PL efficiency. The heteronanostructures
(SR = 1/7) exhibit the highest PL efficiency; its PL intensity of the 5D0–7F2 emission at 620 nm is 27% higher than that of the YVO4:Eu3+ nanocrystals under the same conditions. 相似文献
13.
Wenzhi Sun Liyan Fan Xinxin Zhang Denghu Wei Mengmeng Jiao Wenlong Xu Hongwu Zhang 《Journal of the American Ceramic Society》2023,106(4):2443-2454
We report orange-emitting Sr8La0.5Na0.5Mg1.5(PO4)7:Eu2+ (SLNMPO-0.5:Eu2+) and Sr7LaNaMg1.5(PO4)7:Eu2+ (SLNMPO-1:Eu2+) phosphors with broad emission bands covering from 450 to 800 nm. The phosphors can be excited by n-ultraviolet and blue light efficiently. Their crystal structure, diffuse reflection spectra, photoluminescence (PL) spectra, fluorescence decay curves and thermal stability were investigated systematically. Under the excitation of 365 and 400 nm, SLNMPO-0.5:Eu2+ and SLNMPO-1:Eu2+ both exhibit better PL properties and contain more red emissions than SMPO:Eu2+. CIE coordinates of SLNMPO-0.5:Eu2+ and SLNMPO-1:Eu2+ under 365 nm excitation are (0.460, 0.497) and (0.457, 0.494), respectively. Furthermore, high-quality warm white light can be generated by fabricating warm white light-emitting diode (WLED) devices with 370 nm LED chips, BaMgAl10O17:Eu2+ commercial blue phosphor and orange-emitting SLNMPO-0.5:Eu2+ (or SLNMPO-1:Eu2+) phosphor. The correlated color temperature, Ra and color coordinates are 3880 K, 94.05, (0.3895, 0.3922) and 3736 K, 91.73, (0.4005, 0.4078) for the fabricated WLED devices with SLNMPO-0.5:Eu2+ and SLNMPO-1:Eu2+, respectively. The excellent performances indicate that SLNMPO-0.5:Eu2+ and SLNMPO-1:Eu2+ have great potential to be attractive candidates in the application of warm WLEDs. 相似文献
14.
In this paper, Ba3P4O13:Eu2+ phosphor was synthesized by a solid-state reaction. The photoluminescence (PL) emission spectrum and luminescence decay kinetics confirm that the doped Eu2+ ions can occupy two different Ba2+ sites. The PL excitation spectrum shows a broad band matching well with the emission of near-UV chip. Ba3P4O13:Eu2+ is a promising phosphor for near-UV chip excited white LEDs. The doped Eu3+ ions can also be reduced to Eu2+ ions in air atmosphere at high temperature. Charge compensation mechanism is applied to explain this kind of abnormal reduction. 相似文献
15.
Go Okada Kenji Shinozaki Daiki Shiratori Noriaki Kawaguchi Takayuki Yanagida 《Ceramics International》2019,45(7):9376-9380
Radio-photoluminescence (RPL), which is an infrequent phenomenon observed in phosphor materials where new luminescent centre is generated by interacting with ionizing radiation, was observed in Eu-doped BaAlBO3F2 (BABF) glass-ceramics. The as-prepared material shows photoluminescence (PL) only due to the 4f‐4f transitions of Eu3+ whereas an additional broad emission band appears around 510?nm, which is due to the 5d‐4f transitions of Eu2+. The appearance of the Eu2+ as a new emission centre is an evidence of RPL. The RPL in this system is based on intra-valence reduction of Eu ion (Eu3+→Eu2+), which was confirmed as a decrease of PL intensity by Eu3+ and increase of PL intensity by Eu2+ as a function of irradiation dose. Moreover, additional RPL centre is observed after heat-treatment of irradiated material, which is seen as a broad PL peak centering around 480?nm. Based on the luminescence features, the latter RPL is characterized to defect-related luminescence. 相似文献
16.
《Ceramics International》2020,46(8):12111-12119
The Na+ co-doped CaTiO3:Eu3+ powders were produced through the solution combustion method. The phase structure and optical properties of the synthesized samples were adequately characterized by X-ray diffraction (XRD), photoluminescence (PL) spectra, ultraviolet–visible (UV–vis) diffuse reflection spectroscopy and scanning electron microscopy (SEM). The XRD patterns revealed that a low level of Eu3+ doping could not cause lattice distortion of CaTiO3. Photoluminescence (PL) displayed the CaTiO3:0.5% Eu3+ sample synthesized at 900 °C has the weakest PL emission and the low electrons and holes recombination rate. The morphology of the sample was small nanoscale spherical particles. The UV–vis diffuse reflection spectra proved that doping Na+ and Eu3+ enlarged the absorption region and reduced band energy of pure CaTiO3. The photocatalytic properties of Na+ co-doped CaTiO3:Eu3+ samples were investigated via degrading methylene blue (MB) under ultraviolet light irradiation. The CaTiO3:0.5% Eu3+, 0.5% Na+ sample, by contrast, exhibited the greatest photocatalytic property and the degradation rate was as high as 96.62%, which makes it a promising multi-functional material (photocatalytic material and red phosphor) for decreasing organic pollution in water. 相似文献
17.
R. Klement K. Drdlíková M. Kachlík D. Drdlík D. Galusek K. Maca 《Journal of the European Ceramic Society》2021,41(9):4896-4906
Transparent Eu3+-doped (0.05–0.15 at. %) alumina ceramics with fine-grained microstructure were prepared and studied in terms of optical properties and photoluminescence (PL). The light transmission through ceramics up to dopant concentrations 0.125 at. % is dominated by birefringence scattering at grain boundaries. As confirmed by HRTEM/EDS element mapping, high photoluminescence intensity was achieved as the result of the dopant segregation at grain boundaries. The PL emission spectra of Al2O3:Eu3+ ceramics exhibited red light emissions with the highest intensity (394 nm excitation) for material containing 0.125 at. % of Eu3+. The luminescence decay was single-exponential with a lifetime ~1.5 ms. The post-sintering reduction of Eu3+→Eu2+ under an H2 atmosphere (at 1300 °C) was difficult. Two simultaneously coexisting Eu2+ emitting PL centers were identified, one emitting blue light with average decay constant of 150 ns, and the other green light (more intense) with average decay constant of 1.3 μs. 相似文献
18.
Photoluminescence Enhancement of SiO2‐Coated LaPO4:Eu3+ Inverse Opals by Surface Plasmon Resonance of Ag Nanoparticles
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Jun Li Zhengwen Yang Bo Shao Jianzhi Yang Yida Wang Jianbei Qiu Zhiguo Song 《Journal of the American Ceramic Society》2016,99(10):3330-3335
The surface plasmon resonance of Ag nanoparticles (NPs) and SiO2 coating had been extensively employed to improve the photoluminescence (PL) intensity of nanomaterials. In the article, the LaPO4:Eu3+ inverse opal photonic crystals were fabricated via combining a self‐assembly process with a sol–gel method. The SiO2 shells were formed on the skeleton surface of LaPO4:Eu3+ inverse opals and the Ag NPs were added into the voids of LaPO4:Eu3+ inverse opals with the SiO2 shells. The influence of the SiO2 shells and Ag NPs on the PL of the LaPO4:Eu3+ inverse opals were investigated. About sevenfold luminescence enhancement of LaPO4:Eu3+ inverse opals was obtained by the coordination action of surface plasmon absorption effects of Ag nanoparticle and silica‐coating effects. The luminescence enhancement mechanisms of LaPO4:Eu3+ inverse opals were discussed. 相似文献
19.
Using the conventional high temperature solid‐state reaction method Ba2Ca(PO4)2:Eu2+ phosphors were prepared. The phase structure, photoluminescence (PL) properties, and the PL thermal stability of the samples were investigated, respectively. Under the excitation at 365 nm, the phosphor exhibited an asymmetric broad‐band blue emission with peak at 454 nm, which is ascribed to the 4f–5d transition of Eu2+. It was further proved that the dipole–dipole interactions results in the concentration quenching of Eu2+ in Ba2Ca1?x (PO4)2:xEu2+ phosphors. When the temperature turned up to 150°C, the emission intensity of Ba2Ca0.99(PO4)2:0.01Eu2+ phosphor was 59.07% of the initial value at room temperature. The activation energy ΔE was calculated to be 0.30 eV, which proved the good thermal stability of the sample. All the properties indicated that the blue‐emitting Ba2Ca(PO4)2:Eu2+ phosphor has potential application in white LEDs. 相似文献
20.
《Ceramics International》2016,42(12):13476-13484
A novel green phosphor composed of Ca4LaO(BO3)3:Tb3+ (CLBO:Tb) has been synthesized by a combustion method with urea. Its crystal structure, temperature-dependent luminescence, and quantum yield (QY) have been characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra with heating device and integrate sphere. No concentration quenching has been observed when all of La3+ ions are substituted with Tb3+ ions. Green phosphor Ca4TbO(BO3)3 (CTBO) has 200% luminescence intensity of commercially available phosphor LaPO4:Ce, Tb (LPO:Ce, Tb) under 378 nm excitation. The QY of CTBO is as high as 98%. Through a Dexter energy transfer mechanism, Eu3+ ions are efficiently sensitized by Tb3+, resulting in an emission with color tunable from green to red under ultraviolet excitation. A possible mechanism of energy transfer from Tb3+ to Eu3+ has been investigated by PL spectra and decay measurements. The energy transfer efficiency from Tb3+ to Eu3+ increases linearly with concentration of Eu3+ increasing. 相似文献