Upconverting Ho–Yb doped titanate nanotubes

Pedroni, Marco; Piccinelli, Fabio; Polizzi, Stefano; Speghini, Adolfo; Bettinelli, Marco; Haro‐González, P.

doi:10.1016/j.matlet.2012.04.096

Cited by 16 publications

(14 citation statements)

References 25 publications

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“…The linked organic groups may then serve as a template for subsequent chemical reactions, e.g. polymer grafting for nanocomposite applications [78][79][80].…”

Section: Physical and Chemical Properties Of Titanate Nanomaterialsmentioning

confidence: 99%

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Kukovecz

Kordás

Kiss

2016

Surface Science Reports

104

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Titanates are salts of polytitanic acid that can be synthesized as nanostructures in a great variety concerning crystallinity, morphology, size, metal content and surface chemistry.Titanate nanotubes (open-ended hollow cylinders measuring up to 200 nm in length and 15 nm in outer diameter) and nanowires (solid, elongated rectangular blocks with length up to 1500 nm and 30-60 nm diameter) are the most widespread representatives of the titanate nanomaterial family. This review covers the properties and applications of these two materials from the surface science point of view. Dielectric, vibrational, electron and X-ray spectroscopic results are comprehensively discussed first, then surface modification methods including covalent functionalization, ion exchange and metal loading are covered. The versatile surface chemistry of onedimensional titanates renders them excellent candidates for heterogeneous catalytic, photocatalytic, photovoltaic and energy storage applications, therefore, these fields are also reviewed.

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“…The linked organic groups may then serve as a template for subsequent chemical reactions, e.g. polymer grafting for nanocomposite applications [78][79][80].…”

Section: Physical and Chemical Properties Of Titanate Nanomaterialsmentioning

confidence: 99%

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Kukovecz

Kordás

Kiss

2016

Surface Science Reports

104

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“…Yb 3+ -sensitized fluoride NCs have been believed to be one of the most efficient upconverters due to low energy lattice phonons which can minimize the quenching effect of the excited state of lanthanide ions [16][17][18] Nikon multiple camera (model D7100) without adding any filter. All the measurements were performed at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Colloidal β-KYF₄:Yb³⁺,Er³⁺/Tm³⁺nanocrystals: tunable multicolor up-conversion luminescence from UV to NIR regions

2015

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Pure β-KYF 4 nanocrystals codoped with Er 3+ /Yb 3+ and Tm 3+ /Yb 3+ were successfully synthesized via the thermal decomposition of trifluoroacetate precursors using oleic acid and octadecylene as coordinate solvents. The up-conversion optical properties of the β-KYF 4 nanocrystals with different lanthanide (Ln)-doped ions (Yb 3+ /Er 3+ , Yb 3+ /Tm 3+ ) were investigated. It is found that the colloidal dispersion of β-KYF 4 :Yb,Er/Tm nanocrystals display strong multiple up-conversion emission spanning from the deep UV-to-NIR region under 980 nm excitation. Pure β-KYF 4 nanocrystals codoped with Er 3+ /Yb 3+ and Tm 3+ /Yb 3+ can emit the bright eye-visible blue, green, yellow, and red emissions by adjusting concentration of Yb 3+ sensitizer ion and Er 3+ or Tm 3+ activator ions. Moreover, the UC luminescent colors can be tuned for the four colors from blue to green to yellow and finally to red emission in the average particle size, X-ray wavelength (0.15405 nm), the diffraction angle and full-width at half-maximum, respectively.The morphology and size of Yb 3+ ,Er 3+ /Tm 3+ codoped KYF 4 NCs are analyzed by TEM and HRTEM. Fig.2 shows the TEM images of KYF 4 :20% Yb 3+ /2% Er 3+ and KYF 4 :25% Yb 3+ /0.2% Tm 3+ NCs, respectively. It is shown that as-synthesized KYF 4 :Yb 3+ ,Er 3+ /Tm 3+ NCs contain smaller hexagonal nanorods particles and nanoplates with good monodispersity. From Fig. 2a,b the average grain size for KYF 4 :20% Yb/2% Er and KYF 4 :25% Yb/0.2% Tm NCs are calculated from random 100 nanoparticle to be 16nm, 18nm, respectively , which are in good consistent to XRD analysis result calculated by scherrer's formula. The lattice fringes are obviously observed in HR-TEM images of KYF 4 :Yb,Er/Tm ( Fig. 2c,d ), which indicated that as-synthesized KYF 4 NCs possessed highly crystallinity. The HRTEM images (Fig. 2c) of as-synthesized nanocrystals showed clear lattice fringes with a interplanar spacing of d = 0.33 nm, which corresponds to the (221) lattice plane of the hexagonal phase KYF 4 . In addition, the interplanar distances of 0.21nm was also observed by HR-TEM images in Fig. 2d, corresponding to the (600) lattice planes of the hexagonal phase KYF 4 , which was consistent with the XRD analysis. The corresponding elemental composition of KYF 4 codoped with 20% Yb 3+ /2% Er 3+ and 25% Yb 3+ /0.2% Tm 3+ NCs were obtained by the EDS analysis, as shown in Fig.2f.The EDS result for KYF 4 :20%Yb/2%Er (Fig. 2e) demonstrates that as-synthesizedNCs are mostly consist of K, Y, Yb, Er and F. The EDS result for KYF 4 :25% Yb/0.2% Tm as-synthesized NCs are mostly consist of K, Y, Yb, Tm and F. Based on

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“…As can be seen in Figure 16(c), when excited with 452 nm, emission spectra in the range of 500-700 nm show dominant emissions from 5 F 4 / 5 S 2 → 5 I 8 transitions at about 545, 554, and 559 nm, and emission from 5 F 5 → 5 I 8 transition with maximum centred at 665 nm. Emissions from the same transitions can also be observed in samples sensitized with Yb 3+ ions, when excitation wavelength was 980 nm that corresponds to the absorption of Yb 3+ ions, and the mechanism of obtaining luminescence is upconversion [50].…”

Section: Holmiummentioning

confidence: 80%

“…The synthesis has been used to produce homogeneous, high-purity, crystalline nanostructured RE-doped TiO 2 with different morphologies: nanotubes, nanobelts, nanowires or spherical nanoparticles. Alkoxide Ti precursors and water-soluble RE precursors are activated by acids or bases prior to the temperature treatments in Teflon-liners autoclave up to several days [28,[44][45][46][47][48][49][50][51][52][53]. Obtained precipitates should be washed to neutral pH [47] before calcination in order to gain well-defined TiO 2 nanoparticles.…”

Section: Synthesis Of Rare Earth-doped Anatase Tio 2 Nanoparticlesmentioning

confidence: 99%

Rare Earth‐Doped Anatase TiO2 Nanoparticles

Đorđević¹,

Milićević²,

Dramićanin³

2017

Titanium Dioxide

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Titanium dioxide is a wide band-gap semiconductor of high chemical stability, nontoxicity and large refractive index. Because of the high photocatalytic activity, anatase is a preferred TiO 2 form in many applications such as for air and water splitting and purification. Doping of TiO 2 with various ions can increase the photocatalytic activity by enhancing light absorption in visible region and can alter structure, surface area and morphology. Also, by doping TiO 2 with optically active ions, visible light via up-or downconversion luminescence can be produced. It is a challenge to optimize the synthesis procedure to incorporate rare earth RE 3+ ions into the TiO 2 structure due to large mismatch in ionic radii between the Ti 4+ and RE 3+ and because of the charge imbalance. Visible (VIS) and ultraviolet (UV) luminescence of several RE 3+ ions can be obtained when incorporated into anatase TiO 2 , also affecting microstructural characteristics of TiO 2. It is of great importance to summarize publications on rare earth-doped anatase TiO 2 nanoparticles to find correct TiO 2-RE combination to sensitize trivalent rare earths luminescence, as well as to predict or tune structural and morphological properties. A better understanding on these topics may progress the desired design of this kind of material towards specific applications.

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Upconverting Ho–Yb doped titanate nanotubes

Cited by 16 publications

References 25 publications

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Colloidal β-KYF₄:Yb³⁺,Er³⁺/Tm³⁺nanocrystals: tunable multicolor up-conversion luminescence from UV to NIR regions

Rare Earth‐Doped Anatase TiO2 Nanoparticles

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Upconverting Ho–Yb doped titanate nanotubes

Cited by 16 publications

References 25 publications

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Colloidal β-KYF4:Yb3+,Er3+/Tm3+nanocrystals: tunable multicolor up-conversion luminescence from UV to NIR regions

Rare Earth‐Doped Anatase TiO2 Nanoparticles

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Colloidal β-KYF₄:Yb³⁺,Er³⁺/Tm³⁺nanocrystals: tunable multicolor up-conversion luminescence from UV to NIR regions