Abstract:Cluster-like, flower-like and sphere-like EuPO 4 nano/microstructures and uniform core-shell SiO 2 @EuPO 4 nanostructures have been controllably synthesized by the hydrothermal route and co-precipitation method, respectively. The as-synthesized products are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). The possible formatio… Show more
“…Also, the PL intensity of the magnetic‐dipole transition of 5 D 0 – 7 F 1 is stronger than that of the electronic‐dipole transition of 5 D 0 – 7 F 2 . In addition, the same situation can be observed in hexagonal EuPO 4 ·H 2 O nanorods and nanowires, EuPO 4 nano/microstructures and core–shell SiO 2 @EuPO 4 nanostructures in the literature [17–21]. Moreover, Yan et al concluded that the dominant 5 D 0 − 7 F 1 emission for Eu 3+ ions in the hexagonal environment of LnPO 4 :Eu 3+ nanowires originated from a magnetic‐dipole transition [24].…”
Section: Resultsmentioning
confidence: 64%
“…Phase transition temperature was observed at approximately 700°C [17]. Significant effort has been made to develop various monoclinic and hexagonal EuPO 4 nanostructures such as nanoparticles, nanorods, nanowires, and nanospheres, and their luminescent properties have been investigated [17][18][19][20][21]. However, there are no known reports about the fabrication of uniform and monodisperse EuPO 4 hollow spheres in the literature up to now.…”
Submicrometre-sized EuPO 4 hollow spheres were synthesised by utilising the colloidal spheres of Eu(OH)CO 3 as the sacrificial template, for the first time. The EuPO 4 hollow spheres were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence, respectively. The EuPO 4 hollow spheres exhibit red colour emission from 5 D 0-7 F J (J = 1, 2, 3, 4) transitions of the Eu 3+ ions. The obtained EuPO 4 hollow spheres may have potential applications in cell biology, drug release, diagnosis, due to the high chemistry stability and luminescence function.
“…Also, the PL intensity of the magnetic‐dipole transition of 5 D 0 – 7 F 1 is stronger than that of the electronic‐dipole transition of 5 D 0 – 7 F 2 . In addition, the same situation can be observed in hexagonal EuPO 4 ·H 2 O nanorods and nanowires, EuPO 4 nano/microstructures and core–shell SiO 2 @EuPO 4 nanostructures in the literature [17–21]. Moreover, Yan et al concluded that the dominant 5 D 0 − 7 F 1 emission for Eu 3+ ions in the hexagonal environment of LnPO 4 :Eu 3+ nanowires originated from a magnetic‐dipole transition [24].…”
Section: Resultsmentioning
confidence: 64%
“…Phase transition temperature was observed at approximately 700°C [17]. Significant effort has been made to develop various monoclinic and hexagonal EuPO 4 nanostructures such as nanoparticles, nanorods, nanowires, and nanospheres, and their luminescent properties have been investigated [17][18][19][20][21]. However, there are no known reports about the fabrication of uniform and monodisperse EuPO 4 hollow spheres in the literature up to now.…”
Submicrometre-sized EuPO 4 hollow spheres were synthesised by utilising the colloidal spheres of Eu(OH)CO 3 as the sacrificial template, for the first time. The EuPO 4 hollow spheres were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence, respectively. The EuPO 4 hollow spheres exhibit red colour emission from 5 D 0-7 F J (J = 1, 2, 3, 4) transitions of the Eu 3+ ions. The obtained EuPO 4 hollow spheres may have potential applications in cell biology, drug release, diagnosis, due to the high chemistry stability and luminescence function.
“…When the size of the nanoparticles decreased, the ratio of Eu 3+ ions in the surface of nanoparticles would be increased. Therefore, the decrease of the symmetry around the Eu 3+ ions would lead to the enhancement of the 5 D 0 → 7 F 2 transition 32,36,37 . To further understand the f-f transition and the local symmetry properties of Eu 3+ ions in the LaPO 4 crystal lattice, the optical transition strength parameters (Ω 2 and Ω 4 ) were calculated by the well-known Judd-Ofelt (J-O) theory.Figure 6Excitation spectra of the products: S1, S2 and S3.Figure 7Emission spectra of the products: S1, S2 and S3.…”
The novel submicro-spheres SiO2@LaPO4:Eu@SiO2 with core-shell-shell structures were prepared by connecting the SiO2 submicro-spheres and the rare earth ions through an organosilane HOOCC6H4N(CONH(CH2)3Si(OCH2CH3)3 (MABA-Si). The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (IR). It is found that the intermediate shell of the submicro-spheres was composed by LaPO4:Eu nanoparticles with the size of about 4, 5–7, or 15–34 nm. A possible formation mechanism for the SiO2@LaPO4:Eu@SiO2 submicro-spheres has been proposed. The dependence of the photoluminescence intensity on the size of the LaPO4:Eu nanoparticles has been investigated. The intensity ratios of electrical dipole transition 5D0 → 7F2 to magnetic dipole transition 5D0 → 7F1 of Eu3+ ions were increased with decreasing the size of LaPO4:Eu nanoparticles. According to the Judd-Ofelt (J-O) theory, when the size of LaPO4:Eu nanoparticles was about 4, 5–7 and 15–34 nm, the calculated J-O parameter Ω2 (optical transition intensity parameter) was 2.30 × 10−20, 1.80 × 10−20 and 1.20 × 10−20, respectively. The increase of Ω2 indicates that the symmetry of Eu3+ in the LaPO4 lattice was gradually reduced. The photoluminescence intensity of the SiO2@LaPO4:Eu@SiO2 submicro-spheres was unquenched in aqueous solution even after 15 days.
“…Xu et al have synthesized a luminescent and mesoporous core-shell structured Gd 2 O 3 :Eu 3+ @SiO 2 nanocomposite and make it as a drug carrier [19]. In our previous studies, we have synthesized SiO 2 @EuPO 4 by co-precipitation using triethyl phosphate [20]. It was found that the core-shell nanostructure can significantly improve the emission strength of the material.…”
SiO
2
@GdPO
4
:Tb@SiO
2
nanoparticles with core-shell-shell structure were successfully synthesized by a cheap silane coupling agent grafting method at room temperature. This method not only homogeneously coated rare-earth phosphate nanoparticles on the surface of silica spheres but also saved the use of rare-earth resources. The obtained nanoparticles consisted of SiO
2
core with a diameter of approximately 210 nm, GdPO
4
:Tb intermediate shell with thickness of approximately 7 nm, and SiO
2
outer shell with thickness of approximately 20 nm. This unique core-shell-shell structured nanoparticles exhibited strong luminescence properties compared with GdPO
4
:Tb nanoparticles. The core-shell-shell structured nanoparticles can effectively quench the intrinsic fluorescence of bovine serum albumin through a static quenching mode. The as-synthesized nanoparticles show great potential in biological cell imaging and cancer treatment.
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