Tuning the crystalline phase and morphology of the YF3:Eu3+ microcrystals through fluoride source

Sarkar, Shyam; Mahalingam, Venkataramanan

doi:10.1039/c3ce40554k

Cited by 35 publications

(23 citation statements)

References 39 publications

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“…Sufficient F − ions were provided around Yb 3+ ions due to the high F − /Yb 3+ molar ratio. Moreover, the capping effect of F − would decrease the chemical potential of the crystal, thus overcome the energy barrier of the phase transition as explained by Sarkar et al . Our results show that F − ions have positive effects on the formation of the hexagonal NaYbF 4 crystals.…”

Section: Resultssupporting

confidence: 70%

Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors

Jiang

Shen

et al. 2018

J Am Ceram Soc

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We demonstrate that self‐propagating sintering reaction could be activated and dramatically enhanced by laser excitation of ion dopants in the solid‐state reactants. Near‐resonant laser absorption and subsequent nonradiative decays make the solid‐state reactants be sintered efficiently while ionic excitations catalyze self‐propagating solid‐state reactions. As a prototype demo, we synthesized white light upconversion phosphors NaYbF4:Pr3+/Gd3+. A continuous‐wave laser at 980 nm was used to populate Yb3+ ions in YbF3 to excited level, which react with NaF to preform NaYbF4 nuclei. The preformed nuclei enhanced laser excitation and energy transfer to those ions that could not be directly excited by the pump laser and thus enabled self‐propagating solid‐state sintering synthesis of NaYbF4 microcrystals at quite low laser powers. Laser excitation of Yb3+ ions could also benefit facile rare‐earth ion doping through activated self‐propagating reactions. Gd3+ and Pr3+ ions were doped in NaYbF4 by simply adding Gd3+ and Pr3+ ionic oxides or fluorides in the raw materials. In addition, Gd3+ ions doping in F− anions ambient could transform the NaYbF4 microcrystal phase from cubic to hexagonal and tune upconversion photoluminescence. This synthetic method can be widely applied to synthesize many other solid‐state compounds, perovskite solar cells, photocatalysts, solid oxide fuel cells, and so forth.

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Section: Resultssupporting

confidence: 70%

Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors

Jiang

Shen

et al. 2018

J Am Ceram Soc

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“…In the aqueous solution, NaBF 4 releases the F − ion slowly, which induces the nucleation and growth to take place at the same time, thus resulting in the formation of smaller particles . The smaller nanoparticles self‐assemble to reduce the high surface energy and produce various morphologies.…”

Section: Resultsmentioning

confidence: 99%

Shape‐Tunable Selective Synthesis of Bismuth Fluoride Nanostructures for Versatile Applications

Bharat

Nagaraju

Raju

et al. 2018

Part & Part Syst Charact

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pacitors, and sensors due to the enhanced properties arising from the nanobuilding blocks and the way they are arranged. [2] Hollow hierarchical and porous microand nanostructures have attracted significant attention because of their interesting features, like low densities, large interior spaces, high specific surface areas with a broad range of potential applications in the fields of water treatment, energy conversion, gas sensing, catalysis, and drug delivery. [3] Similarly, synthesis of cube-like morphology also gained importance due to its structure and crystal facet exposure which helps in improving the properties such as gas sensing and catalysis. [4] The rare-earth ions doped micro/nanoparticles have enticed researchers because of their broad range of applications in solid-state light-emitting diodes and other optoelectronic devices. [5] In conjunction with the utilization in illumination devices, they are also used as fluorescent labels in biological applications. [6] Among different rare-earth doped materials, fluoride micro/nanoparticles have got more significant importance compared to other materials like oxides, carbonates, vanadates, and garnets, owing to their unique optical properties. [7] The materials show low toxicity, high photochemical stability, and long lifetime. Moreover, fluoride-based materials have low phonon energy (<350 cm −1 ) which reduces the nonradiative relaxation and are expected to improve the quantum efficiency. [8] Although there are lots of reports on rare-earthbased (Y, Ln) fluoride materials, when the rare-earth cations are replaced with Bi 3+ ions, they become more beneficial in economic viewpoint because of their ease of availability, good purification, and low cost, as compared with the rare-earths. Despite many advantages, like their use as cathode materials for batteries and photocatalysis, few reports were found about bismuth-based fluoride materials. [9] Zhao et al. reported the size and shape controlled synthesis of BiF 3 through solvent extraction route. [10] Likewise, Sarkar et al. reported the Ln 3+ doped BiF 3 nanoparticles enclosed in polymer matrix and explained the importance of poly (vinyl pyrrolidine) in reducing the size of the particle. The upconversion and downconversion optical properties were also studied by doping Yb 3+ /Er 3+ and Eu 3+ , respectively. [11] In addition, Escudero et al. reported the BiF 3 synthesis of quasispheres, and the spheres were of few µm size. [12] Recently, Feng et al. demonstrated the photocatalytic activity of BiF 3 particles under visible light illumination. [13] To the best of our knowledge, there were no reports found on the A facile approach for shape-tunable synthesis of bismuth fluoride nanoparticles is reported. The approach is based on the homogeneous precipitation of precursor materials in mixed solvents (H 2 O and ethylene glycol) and only ethylene glycol. The influencing factors on the morphology of the particles, i.e., solvent ratio, F/Bi ratio, and ethylenediaminetetraacetic acid, are studied in detail, a...

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“…It offers several advantages such as excellent control over particle size and shape, high yields, the use of cheap raw materials, and a post‐treatment which does not require heat . Solvothermal methods also present several disadvantages such as: a) the use of high pressure and high temperature which does not allow the in situ introduction of several functionalities which will decompose under those conditions, b) long reaction times, c) formation of carbon‐based side products which complicates the purification process . The hydrothermal method solves some of these issues, and can be seen as a green method as no toxic waste products are generated.…”

Section: Introductionmentioning

confidence: 99%

“…‐, However, a post‐heat treatment (annealing) at high temperature is often required , The colloidal route (a variation of the coprecipitation method), performed at low (< 100 0 C) temperature, offers the mildest conditions, but this method has so far not been performed in water.…”

Section: Introductionmentioning

confidence: 99%

Versatile, Fast, and Easy One‐Step Method for the Synthesis of Hydrophilic Lanthanide‐Doped Nanoparticles

Graña-Suárez

Verboom

Sarkar³

et al. 2016

ChemistrySelect

Self Cite

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The preparation of hydrophilic lanthanide-doped nanoparticles (NPs) following a versatile one-step colloidal method at low temperature and short reaction time with different doped lanthanides, capping ligands, and fluoride sources is presented. The photoluminescence of the particles, via both downshifting (DS) and up-conversion (UC), was easily tuned from blue or green by simply changing the lanthanides used. When using the same core type of particles, the size and the photoluminescence intensity were tuned by changing the fluoride source or the capping ligand used: the size of the DSNPs varied from 9 nm (PAA) to 24 nm (PEI) when changing the capping ligand, while if PAA was used as capping ligand, the nanoparticles presented the most intense emission bands. Supramolecular host groups were introduced on the surface of the UCNPs by grafting cyclodextrin (CD) groups onto the capping ligand PiBMA prior to particle synthesis, reaching a CD surface density of 0.28 CD nm -2 . In this case, a small particle size (11.7 nm) and strong UC emission bands were observed.

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Tuning the crystalline phase and morphology of the YF3:Eu3+ microcrystals through fluoride source

Cited by 35 publications

References 39 publications

Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors

Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors

Shape‐Tunable Selective Synthesis of Bismuth Fluoride Nanostructures for Versatile Applications

Versatile, Fast, and Easy One‐Step Method for the Synthesis of Hydrophilic Lanthanide‐Doped Nanoparticles

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Tuning the crystalline phase and morphology of the YF3:Eu3+ microcrystals through fluoride source

Cited by 35 publications

References 39 publications

Laser excitation‐activated self‐propagating sintering of NaYbF4:Pr3+/Gd3+ white light microcrystal phosphors

Laser excitation‐activated self‐propagating sintering of NaYbF4:Pr3+/Gd3+ white light microcrystal phosphors

Shape‐Tunable Selective Synthesis of Bismuth Fluoride Nanostructures for Versatile Applications

Versatile, Fast, and Easy One‐Step Method for the Synthesis of Hydrophilic Lanthanide‐Doped Nanoparticles

Contact Info

Product

Resources

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Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors

Laser excitation‐activated self‐propagating sintering of NaYbF₄:Pr³⁺/Gd³⁺ white light microcrystal phosphors