Preparation and characterization of Ce-doped HfO2 nanoparticles

Gálvez-Barboza, Saúl; González, L.; Puente-Urbina, Bertha; Saucedo‐Salazar, Esmeralda; Garcı́a-Cerda, L.A.

doi:10.1016/j.jallcom.2014.12.165

Cited by 16 publications

(10 citation statements)

References 23 publications

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“…As can be seen from figure 1, similarity exists between the different phases. Moreover, metastable tetragonal or cubic phases can also be stabilized at room temperature by doping the HfO 2 matrix with RE atoms, as recently demonstrated for Ce-doped HfO 2 nanoparticles [10] and Ladoped HfO 2 films [11]. The tetragonal HfO 2 phase was also confirmed by XRD in the Er 3+ -doped SiO 2 -HfO 2 waveguide [8].…”

Section: Introductionsupporting

confidence: 55%

Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Demoulin¹,

Beainy²,

Castro³

et al. 2018

Nano Futures

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Structural, chemical, and luminescence properties of Pr 3+-doped HfSiO x layers fabricated by radiofrequency magnetron sputtering were examined as a function of annealing temperature. Phase separation between SiO 2 and HfO 2 as well as the location of Pr 3+ dopants were investigated using atom probe tomography and transmission electron microscopy while optical properties of Pr 3+ ions were studied using photoluminescence measurements. As a result, (i) we evidenced the location of the Pr 3+ dopants in the HfO 2 phase while the SiO 2 phase was discovered to be free of these dopants, (ii) the HfO 2 phase was identified to crystallize in the cubic phase until 1050°C annealing, (iii) no Pr clusters were detected as function of annealing, and (iv) luminescence properties were discussed in regard to the location of Pr in the HfO 2 cubic phase.

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Section: Introductionsupporting

confidence: 55%

Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Demoulin¹,

Beainy²,

Castro³

et al. 2018

Nano Futures

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“…HfO 2 nanoparticles were synthesized by three different methods. Figure a shows transmission electron microscopy (TEM) images of HfO 2 nanoparticles prepared by direct precipitation (I), , microwave-assisted precipitation (II), , and sol–gel precipitation (III). ,, Precipitated particles were initially amorphous as seen from the corresponding X-ray diffraction (XRD) patterns (Figure b). Subsequent calcination at 500 °C induced a transformation into a monoclinic crystal phase.…”

Section: Resultsmentioning

confidence: 99%

“…The sol–gel method was performed according to previous reports. ,, In short, 0.05 mol of citric acid was added to 24 mL of ddH 2 O to yield 31 mL of 2 M aqueous citric acid solution. To this, 2 g (0.00625 mol) of HfCl 4 (or Gd(NO 3 ) 3 × 6H 2 O for gadolinium oxide) was added and stirred overnight.…”

Section: Experimental Sectionmentioning

confidence: 99%

Lanthanide-Doped Hafnia Nanoparticles for Multimodal Theranostics: Tailoring the Physicochemical Properties and Interactions with Biological Entities

Gerken¹,

Keevend²,

Zhang³

et al. 2018

ACS Appl. Mater. Interfaces

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High-Z metal oxide nanoparticles hold promise as imaging probes and radio-enhancers. Hafnium dioxide nanoparticles have recently entered clinical evaluation. Despite promising early clinical findings, the potential of HfO 2 as a matrix for multimodal theranostics is yet to be developed. Here, we investigate the physicochemical properties and the potential of HfO 2 -based nanoparticles for multimodal theranostic imaging. Undoped and lanthanide (Eu 3+ , Tb 3+ , and Gd 3+ )-doped HfO 2 nanoparticles were synthesized and functionalized with various moieties including poly-(vinylpyrrolidone) (PVP), (3-aminopropyl)triethoxysilane (APTES), and folic acid (FA). We show that different synthesis routes, including direct precipitation, microwave-assisted synthesis, and sol−gel chemistry, allow preparation of hafnium dioxide particles with distinct physicochemical properties. Sol−gel based synthesis allows preparation of uniform nanoparticles with dopant incorporation efficiencies superior to the other two methods. Both luminescence and contrast properties can be tweaked by lanthanide doping. We show that MRI contrast can be unified with radio-enhancement by incorporating lanthanide dopants in the HfO 2 matrix. Importantly, ion leaching from the HfO 2 host matrix in lysosomal-like conditions was minimal. For Gd:HfO 2 nanoparticles, leaching was reduced >10× compared to Gd 2 O 3 , and no relevant cytotoxic effects have been observed in monocyte-derived macrophages for nanoparticle concentrations up to 250 μg/mL. Chemical surface modification allows further tailoring of the cyto-and hemocompatibility and enables functionalization with molecular targeting entities, which lead to enhanced cellular uptake. Taken together, the present study illustrates the manifold properties of HfO 2 -based nanomaterials with prospective clinical utility beyond radio-enhancement.

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“…However, at 950 • C, four intense diffraction peaks are observed at 2θ = 30.3 • 35 • , 50.3 • and 60 • . These peaks can respectively be attributed to the (111), (200), (220) and (311) lattice planes of HfO 2 that crystallizes in the cubic fluorite type structure with a space group F m3m (JCPDS: n • 53-0550).The stabilization of the cubic form of HfO 2 (c-HfO 2 ) due to the introduction of RE 3+ ions is a well-known effect and has already been highlighted throughout the doping of pure HfO 2 thin layers or nanoparticles[17][18][19]33]. It must be mentioned that, at 1050 • C, new diffraction peaks of weak intensity are detected on the XRD…”

mentioning

confidence: 99%

Correlation of luminescence measurements to the structural characterization of Pr3+-doped HfSiOx

Demoulin

Khomenkova

Labbé

et al. 2021

Journal of Luminescence

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Luminescence and structural properties of Pr 3+ doped HfSiO x thin layer elaborated by magnetron sputtering have been investigated as a function of the annealing temperature. The emission properties of Pr 3+ ions were studied using photoluminescence (PL) and cathodoluminescence (CL) spectroscopies. Phase separation between amorphous SiO 2 and crystallized HfO 2 nano-grains occurring in the HfSiO x matrix has been investigated by atom probe tomography and transmission electron microscopy with particular consideration for the Pr distribution. Both PL and CL measurements evidenced a strong emission originating from Pr 3+ ions in the visible range for an annealing temperature higher than 950 • C. At 950 • C, Pr 3+ ions are clearly located in HfO 2 nano-grains of cubic structure. Regarding PL, no significant changes are observed between 950 • C and 1050 • C. However, CL measurements revealed new emission peaks in the infrared range after an annealing at 1050 • C, corresponding to the appearance of a new orthorhombic crystalline structure of HfO 2 nano-grains in the thin layer. The CL signal evolution as a function of the annealing treatment is discussed in regard to the evolution of structural properties.

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Preparation and characterization of Ce-doped HfO2 nanoparticles

Cited by 16 publications

References 23 publications

Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Lanthanide-Doped Hafnia Nanoparticles for Multimodal Theranostics: Tailoring the Physicochemical Properties and Interactions with Biological Entities

Correlation of luminescence measurements to the structural characterization of Pr3+-doped HfSiOx

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Preparation and characterization of Ce-doped HfO2 nanoparticles

Cited by 16 publications

References 23 publications

Origin of Pr3+ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Origin of Pr3+ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Lanthanide-Doped Hafnia Nanoparticles for Multimodal Theranostics: Tailoring the Physicochemical Properties and Interactions with Biological Entities

Correlation of luminescence measurements to the structural characterization of Pr3+-doped HfSiOx

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Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations

Origin of Pr³⁺ luminescence in hafnium silicate films: combined atom probe tomography and TEM investigations