Effect of pH on the optical and structural properties of HfO2:Ln3+, synthesized by hydrothermal route

Montes, Emilio Fontela; Martínez-Merlin, I.; Guzmán-Olguín, J.C.; Guzmán‐Mendoza, J.; Martı́n, I.R.; Garcı́a-Hipólito, M.; Falcony, C.

doi:10.1016/j.jlumin.2016.03.009

Cited by 22 publications

(8 citation statements)

References 22 publications

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“…In particular, according to Štefanić et al, , hydrous hafnia crystallizes with the formation of m-HfO 2 phase, regardless of pH, during the treatment. In the case of HfO 2 and ZrO 2 , the hydrothermal crystallization proceeded much more slowly in neutral pH conditions than in alkaline conditions. , Similar results were obtained by Montes et al Note that the same influence of the hydrothermal media was observed for ThO 2 NP growth in the present study.…”

Section: Resultssupporting

confidence: 91%

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Size Effects in Nanocrystalline Thoria

et al. 2019

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The facile chemical precipitation method and subsequent thermal treatment were shown to be suitable for preparation of crystalline ThO2 nanoparticles (NPs) in a wide range of particle sizes (from 2.5 to 34.3 nm). The obtained NPs were investigated with X-ray diffraction, high-resolution transmission electron microscopy and X-ray absorption techniques to find out the possible size effects associated with nanocrystalline thoria. For 2.5 nm NPs, the lattice parameter of ThO2 was found to increase by up to 1.1 %, in comparison with the bulk material. The decrease in the particle size was also accompanied by a significant decrease in the Th-Th coordination number.

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Section: Resultssupporting

confidence: 91%

“…In the case of HfO2 and ZrO2, the hydrothermal crystallization proceeded much more slowly in neutral pH conditions than in alkaline conditions. [56][57] Similar results were obtained by Montes et al 58 Note that the same influence of the hydrothermal media was observed for ThO2 NPs growth in the present study.…”

Section: Resultssupporting

confidence: 91%

Size Effects in Nanocrystalline Thoria

et al. 2019

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“…Regarding this point, in literature on subject, it is suggested that presence of dopant ions affects the crystallization kinetics of growing material. [34] SEM and HRTEM images show the presence of particles with different sizes and shapes in ZrO 2 and ZrO 2 :Sm 3þ samples. In these samples, it is possible to observe submicroscopic single crystals, polycrystalline particles, nanoparticles (%10 nm) and aggregated particles.…”

Section: Semmentioning

confidence: 97%

Luminescence from ZrO₂ Nanopowders Doped with Sm³⁺ Ions Processed by Polyol Method at Low Processing Temperature

Martínez-Martínez

Juárez-López

Garcia

et al. 2021

Physica Status Solidi (a)

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ZrO2 and ZrO2:Sm3+ nanopowders are synthesized by means of polyol method, from [Zr(NO3)2.xH2O] and (SmCl3·6H2O) precursors dissolved in a diethylene glycol medium. X‐ray diffraction (XRD) results show polymorphic powders because monoclinic structure and tetragonal are exhibited. The crystal size is estimated by Scherrer formula; an averaged crystallite size of 9 nm is obtained. Surface morphology study, by means of SEM, evidences multiform particles, some with straight edges associated with monoclinic or tetragonal structure. The chemical composition microanalysis results indicate agreement with ideal stoichiometry for ZrO2 and ZrO2:Sm3+ powders. The photoluminescence emission spectra show that maximum intensity is reached at λ = 614 nm due to transition 4G5/2→6H7/2, exciting with λex = 240 nm, which corresponds to sample ZrO2:Sm3+ (0.75 at%); this sample is labeled as M3. Very similar results are obtained by cathodoluminescence studies. On the contrary, exciting with λex = 380 nm (monitoring emission band peaked at 614 nm), emission bands of host lattice and ZrO2:Sm3+ are favored simultaneously. The luminescent quenching phenomenon occurs when doping concentration (Sm3+ ions) is >=0.75 at%. The photoluminescent emission exhibits a reddish orange color, characteristic of Sm3+ ions, and yellowish‐orange for cathodoluminescence emission.

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“…[37,38]. They have been synthesized through a variety of physical and chemical techniques, including: Hidrothermal/Solvothermal [39,40,41], solid-state reaction [42], sol-gel [43,44], laser ablation [45,46], sputtering [47], Pechini Method [48], plasma electrolitic oxidation [49], conventional melt-quenching method [50,51], combustion synthesis [52], solvent evaporation method [53,54,55], and co-precipitation process [56]. Among these techniques, spray pyrolysis began to be used for this purpose in the mid-1980s, and it is still used today [57,58]—proving to be a practical, low cost, easy to extrapolate for large area deposition technique.…”

Section: Luminescent Materialsmentioning

confidence: 99%

Spray Pyrolysis Technique; High-K Dielectric Films and Luminescent Materials: A Review

2018

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The spray pyrolysis technique has been extensively used to synthesize materials for a wide variety of applications such as micro and sub-micrometer dimension MOSFET´s for integrated circuits technology, light emitting devices for displays, and solid-state lighting, planar waveguides and other multilayer structure devices for photonics. This technique is an atmospheric pressure chemical synthesis of materials, in which a precursor solution of chemical compounds in the proper solvent is sprayed and converted into powders or films through a pyrolysis process. The most common ways to generate the aerosol for the spraying process are by pneumatic and ultrasonic systems. The synthesis parameters are usually optimized for the materials optical, structural, electric and mechanical characteristics required. There are several reviews of the research efforts in which spray pyrolysis and the processes involved have been described in detail. This review is intended to focus on research work developed with this technique in relation to high-K dielectric and luminescent materials in the form of coatings and powders as well as multiple layered structures.

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Effect of pH on the optical and structural properties of HfO2:Ln3+, synthesized by hydrothermal route

Cited by 22 publications

References 22 publications

Size Effects in Nanocrystalline Thoria

Size Effects in Nanocrystalline Thoria

Luminescence from ZrO₂ Nanopowders Doped with Sm³⁺ Ions Processed by Polyol Method at Low Processing Temperature

Spray Pyrolysis Technique; High-K Dielectric Films and Luminescent Materials: A Review

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Effect of pH on the optical and structural properties of HfO2:Ln3+, synthesized by hydrothermal route

Cited by 22 publications

References 22 publications

Size Effects in Nanocrystalline Thoria

Size Effects in Nanocrystalline Thoria

Luminescence from ZrO2 Nanopowders Doped with Sm3+ Ions Processed by Polyol Method at Low Processing Temperature

Spray Pyrolysis Technique; High-K Dielectric Films and Luminescent Materials: A Review

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Luminescence from ZrO₂ Nanopowders Doped with Sm³⁺ Ions Processed by Polyol Method at Low Processing Temperature