Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Bazzi, Rana; Flores, Marco A.; Louis, Cédric; Lebbou, Kheirréddine; Zhang, W; Dujardin, Christophe; Roux, Stéphane; Mercier, Bruno; Ledoux, Gilles; Bernstein, E.; Perriat, Pascal; Tillement, Olivier

doi:10.1016/j.jcis.2003.10.031

Cited by 185 publications

(152 citation statements)

References 31 publications

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“…[1,2] Several works have been dedicated to the characterization of the optical dispersion and luminescence properties of pure, as well as doped, Gd 2 O 3 . [2][3][4][5][6] Gd 2 O 3 is a wide band gap oxide (5.37-6.36 eV) [6,7] with permittivity values of 10-14 for the epitaxial cubic phase. [8][9][10][11] Recently, Gd 2 O 3 has gained considerable interest as a potential candidate for high-permittivity (high-j) dielectric oxide in order to replace the SiO 2 dielectric in future silicon-based transistors, [8,[12][13][14][15][16][17][18][19] or capacitive sensors.…”

Section: Introductionmentioning

confidence: 99%

“…Regarding the CVD methods, various precursors and growth temperatures have been used: tris(2,4-pentadionato)(1,10-phenanthroline) gadolinium(III) in the range 450-800°C, [15] (1-methoxy-2-methyl-2-propoxy) gadolinium(III), i.e., Gd(mmp) 3 at 300-600°C, [23] Gd(thd) 3 (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) at 500°C. [11] The cubic phase (referring to the formation of stoichiometric Gd 2 O 3 ) has appeared, as a rule, at substrate temperatures higher than 450°C [23] or 500°C.…”

Section: Introductionmentioning

confidence: 99%

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Atomic Layer Deposition of Gadolinium Oxide Films

Kukli

Hatanpää

Ritala

et al. 2007

Chemical Vapor Deposition

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Thin cubic Gd 2 O 3 films are grown by atomic layer deposition (ALD), in the temperature range 300-400°C, using a novel tris(2,3-dimethyl-2-butoxy)gadolinium(III) precursor, Gd[OC(CH 3 ) 2 CH(CH 3 ) 2 ] 3 , and water. The films are crystalline in their as-deposited state. The films contain some residual hydrogen and carbon, and are probably oxygen-deficient in the as-deposited state, causing flat-band shifts in Gd 2 O 3 -based metal-oxide-semiconductor (MOS) capacitor structures. On the other hand, the permittivity of Gd 2 O 3 dielectric layers reaches 16, approximately, when calculated from the relationship between equivalent and physical oxide thicknesses, and breakdown fields as high as 8 MV cm -1 .

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Gadolinium Oxide Films

Kukli

Hatanpää

Ritala

et al. 2007

Chemical Vapor Deposition

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“…The average sizes are 6.1 ± 0.6 nm, 6.0 ± 0.6 nm, 5.3 ± 0.7 nm, and 5.3 ± 0.6 nm for NaY 0. 8 Figure S3, Supporting Information). Such relatively small sizes are compatible for use in many bioanalytical applications.…”

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confidence: 99%

A Strategy to Protect and Sensitize Near-Infrared Luminescent Nd³⁺ and Yb³⁺: Organic Tropolonate Ligands for the Sensitization of Ln³⁺-Doped NaYF₄ Nanocrystals

et al. 2007

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A strategy to sensitize and protect near-infrared (NIR) emitting Nd 3+ and Yb 3+ is presented. Combining protection provided by the inorganic matrix of NaYF 4 nanocrystals and sensitization from tropolonate ligands capped on their surface, the lanthanide cation centered luminescence was observed through the ligand excitation. The extended lanthanide luminescence lifetimes indicate the success of this strategy.Lanthanide-based near-infrared (NIR) emitters have a great potential to serve as bioanalytical reporters for several reasons: (i) NIR photons scatter less than visible photons, improving image resolution. 1 (ii) Biological systems have low native autofluorescence in the NIR energy domain, 2 resulting in higher detection sensitivity due to improved signal-to-noise ratio. (iii) Most luminescent lanthanide complexes are not susceptible to photodecomposition, allowing long or repeated experiments and simplifying sample storage and preparation procedures. Since f−f transitions are Laporte forbidden, 3 free Ln 3+ have low extinction coefficients resulting in low luminescence intensity. Therefore, it is necessary to sensitize these cations through a suitable chromophore ("antenna effect"), 4 an area of research that has been highly active in recent years. 5 However, this approach has intrinsic limitations because lanthanide luminescence is easily quenched through nonradiative routes when the cations are in close proximity to the vibrational overtones of -OH, -NH, and -CH groups present in the sensitizing ligand and/or solvent. 6 This effect is particularly dramatic for NIR emitting Ln 3+ because of relatively small energy gaps between ground and excited electronic states. 6 12 These materials protect lanthanide cations from sources of nonradiative deactivation; however, they have either limited (e.g., LnVO 4 ) or no absorbance in the UV range. Thus, these inorganic materials are not able to sensitize lanthanide luminescence with the efficiency of organic sensitizers.Here we introduce a strategy to overcome the limited lanthanide sensitization by binding organic tropolonate chromophoric groups to the surface of NaYF 4 nanocrystals (NCs), doped with NIR emitting Nd 3+ or Yb 3+ (Scheme 1). Tropolonate (Trop -) was chosen as a capping ligand since it has been previously demonstrated to be a suitable sensitizer for several lanthanide cations emitting in the NIR range when coordinated in KLn(Trop) 4 complexes. 13 These novel systems use the NaYF 4 matrix to protect Ln 3+ from nonradiative deactivations, while a chromophoric coating sensitizes their luminescence.A synthetic method to prepare Nd 3+ or Yb 3+ doped NaYF 4 NCs was developed on the basis of a recently reported synthesis of NaYF 4 NCs (see Supporting Information). 14 The Trop -capped NCs were synthesized using the following procedure. Tropolone was dissolved in methanol, then deprotonated with an equimolar amount of KOH in methanol. Chloroform was added to obtain a 1/1 (v/v) MeOH/CHCl 3 solvent mixture. This solution was added to a purified solution...

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“…Moreover, ultrafine Gd 2 O 3 particles (1-3 nm in size) have been prepared by the most widely used low efficient multistage complex method of col loid chemistry-the polyol method [17][18][19]. In addi tion, the final stage of the preparation of aqueous sus pensions of contrast agents from Gd 2 O 3 nanoparticles obtained by the polyol method includes the long term procedure of the preliminary dialysis.…”

Section: Introductionmentioning

confidence: 99%

Properties of the amorphous-nanocrystalline Gd2O3 powder prepared by pulsed electron beam evaporation

et al. 2013

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Abstract-An amorphous-nanocrystalline Gd 2 O 3 powder with a specific surface area of 155 m 2 /g has been prepared using pulsed electron beam evaporation in vacuum. The nanopowder consists of 20 to 500 nm agglomerates formed by crystalline nanoparticles (3-12 nm in diameter) connected by amorphous-nanoc rystalline strands. At room temperature, the Gd 2 O 3 nanopowder exhibits a paramagnetic behavior. The phase transformations occurring in the powder have been investigated using differential scanning calorimetry and thermogravimetry (40-1400°C). The amorphous phase of the nanopowder is thermally stable up to a tem perature of 1080°C. It has been found that the amorphous phase has an inhibitory effect on the temperature of the polymorphic transformation from the cubic phase into the monoclinic phase. It has been revealed that, compared with the microcrystalline powder, the Gd 2 O 3 nanopowder is characterized by a complete quench ing of photoluminescence.

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Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Cited by 185 publications

References 31 publications

Atomic Layer Deposition of Gadolinium Oxide Films

Atomic Layer Deposition of Gadolinium Oxide Films

A Strategy to Protect and Sensitize Near-Infrared Luminescent Nd³⁺ and Yb³⁺: Organic Tropolonate Ligands for the Sensitization of Ln³⁺-Doped NaYF₄ Nanocrystals

Properties of the amorphous-nanocrystalline Gd2O3 powder prepared by pulsed electron beam evaporation

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Synthesis and properties of europium-based phosphors on the nanometer scale: Eu2O3, Gd2O3:Eu, and Y2O3:Eu

Cited by 185 publications

References 31 publications

Atomic Layer Deposition of Gadolinium Oxide Films

Atomic Layer Deposition of Gadolinium Oxide Films

A Strategy to Protect and Sensitize Near-Infrared Luminescent Nd3+ and Yb3+: Organic Tropolonate Ligands for the Sensitization of Ln3+-Doped NaYF4 Nanocrystals

Properties of the amorphous-nanocrystalline Gd2O3 powder prepared by pulsed electron beam evaporation

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A Strategy to Protect and Sensitize Near-Infrared Luminescent Nd³⁺ and Yb³⁺: Organic Tropolonate Ligands for the Sensitization of Ln³⁺-Doped NaYF₄ Nanocrystals