Microemulsion-based synthesis and luminescence of nanoparticulate CaWO4, ZnWO4, CaWO4:Tb, and CaWO4:Eu

Mai, Marit; Feldmann, Claus

doi:10.1007/s10853-011-5923-8

Cited by 50 publications

(33 citation statements)

References 39 publications

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“…LED 용 형광체로서의 요건을 갖춘 형광물질을 찾기 위하여 단순 산화물(예를 들면 Y 2 O 3 , Gd 2 O 3 등)과는 특성이 다른 산소산염계 물 질, 즉, 인산염계, 3,4) 텅스텐산염계, 5) 붕산염계, 6) 몰리브덴 산염계, 7) 실리콘산염계, 8,9) 바나데이트산염계 10,11) ) 형 광체는 물질에 따라 모체 자체의 엑시톤 흡수 및 방출 밴드가 존재하는 경우가 많아 이를 이용한 형광 효율 향 상이 가능할 뿐만 아니라 우수한 화학적 안정성을 가지 고 있다. 1,2,12,13) 잘 알려진 텅스텐산 모체 물질은 AWO 4 (A = 2가 알칼리 토류 금속) [13][14][15][16][17][18][19] 이며 이미 많은 연구가 보고 되었지만 최근에는 복잡한 조성의 텅스텐산염계 형광체의 연구도 이루어 지고 있다. 예를 들면 희토류 이온이 첨가된 [24][25][26][27][28] 참 고 문 헌…”

Section: 서 론unclassified

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

장¹,

서²,

구³

et al. 2012

Korean. J. Mater. Res.

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Green phosphors K 2 BaW 2 O 8 :Tb 3+ (1.0 mol%) were synthesized by solid state reaction method. Differential thermal analysis was applied to trace the reaction processes. Three endothermic values of 95, 706, and 1055 o C correspond to the loss of absorbed water, the release of carbon dioxide, and the beginning of the melting point, respectively. The phase purity of the powders was examined using powder X-ray diffraction(XRD). Two strong excitation bands in the wavelength region of 200-310 nm were found to be due to the WO 4 2− exciton transition and the 4f-5d transition of Tb 3+ in K 2 BaW 2 O 8. The excitation spectrum presents several lines in the range of 310-380 nm; these are assigned to the 4f-4f transitions of the Tb 3+ ion. The strong emission line at around 550 nm, due to the 5 D 4 → 7 F 5 transition, is observed together with weak lines of the 5 D 4 → 7 F J (J = 3, 4, and 6) transitions. A broad emission band peaking at 530 nm is observed at 10 K, while it disappears at room temperature. The decay times of Tb 3+ 5 D 4 → 7 F 5 emission are estimated to be 4.8 and 1.4 ms, respectively, at 10 and 295 K; those of the WO 4 2− exciton emissions are 22 and 0.92 µs at 10 and 200 K, respectively.

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Section: 서 론unclassified

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

장¹,

서²,

구³

et al. 2012

Korean. J. Mater. Res.

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“…24 One study reported the use of an non-ionic surfactant TritonX-100 for production of CWO NPs within the cyclohexane phase of a microemulsion system. 22 …”

Section: Introductionmentioning

confidence: 99%

Block Copolymer-Encapsulated CaWO₄ Nanoparticles: Synthesis, Formulation, and Characterization

Lee

Rancilio

Poulson

et al. 2016

ACS Appl. Mater. Interfaces

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We envision that CaWO4 (CWO) nanocrystals have the potential for use in biomedical imaging and therapy because of the unique ways this material interacts with high energy radiation (Figure 1). These applications, however, require development of nanoparticle (NP) formulations that are suitable for in vivo applications; primarily, the formulated nanoparticles should be sufficiently small, chemically and biologically inert, and stable against aggregation under physiological conditions. The present study demonstrates one such method of formulation, in which CWO nanoparticles are encapsulated in bio-inert block copolymer (BCP) micelles. For this demonstration, we prepared three different CWO nanocrystal samples having different sizes (3, 10 and 70 nm in diameter) and shapes (elongated vs. truncated rhombic). Depending on the specific synthesis method used, the as-synthesized CWO NPs contain different surfactant materials (citric acid, cetyl trimethylammonium bromide, or a mixture of oleic acid and oleylamine) in the coating layers. Regardless of the type of surfactant, the original surfactant coating can be replaced with a new enclosure formed by BCP materials using a solvent exchange method. Two types of BCPs have been tested: poly(ethylene glycol-block-n-butyl acrylate) (PEG-PnBA), and poly(ethylene glycol-block-D,L-lactic acid) (PEG-PLA). Both BCPs are able to produce fully PEGylated CWO NPs that are stable against aggregation under physiological salt conditions for very long periods of time (for at least three months). The optical and radio-luminescence properties of both BCP-encapsulated and surfactant-coated CWO NPs were extensively characterized. The study confirms that the BCP coating structure does not influence the luminescence properties of CWO NPs.

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“…Much less attention has been paid to the synthesis of CaWO 4 -based particles in the nanometer-size range. In fact, only a few procedures have been reported on the formation of uniform nanospheres, [26] uniform nanorhomboids and nanocubes, [27] or nanoparticles with a less-defined shape, [28] most of them based on the use of cyclohexane/water microemulsions with cetyltrimethylammonium bromide (CTAB) as a stabilizing agent and different cosurfactants (hexanol, [27,28] penthanol [26] ). In this work, we demonstrate that by using cyclohexane/water-based microemulsions, with Triton X as the stabilizing agent and octanol as the cosurfactant, it is possible, under a certain set of experimental conditions, to obtain, for the first time, highly uniform nanoparticles with a new morphology (spindletype) for the CaWO 4 system.…”

Section: Introductionmentioning

confidence: 99%

Microemulsion‐Mediated Synthesis and Properties of Uniform Ln:CaWO₄ (Ln = Eu, Dy) Nanophosphors with Multicolor Luminescence for Optical and CT Imaging

et al. 2017

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Abstract:A new room-temperature method has been developed that yields, for the first time in the literature, uniform and well-dispersed CaWO 4 nanospindles. This method is based on the use of microemulsions consisting of aqueous solutions of Ca 2+ and WO 4 2-precursors, cyclohexane as the organic medium, Triton X-100 as the surfactant, and n-octanol as the cosurfactant. We show that the formation of uniform nanospindles requires a restrictive set of experimental conditions. These particles crystallize into the tetragonal CaWO 4 phase and emit bluegreen luminescence when excited by UV radiation. The reported method is also useful for doping the CaWO 4 spindles with Eu 3+ or Dy 3+ cations, resulting in multicolor emissions (red

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Microemulsion-based synthesis and luminescence of nanoparticulate CaWO4, ZnWO4, CaWO4:Tb, and CaWO4:Eu

Cited by 50 publications

References 39 publications

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

Block Copolymer-Encapsulated CaWO₄ Nanoparticles: Synthesis, Formulation, and Characterization

Microemulsion‐Mediated Synthesis and Properties of Uniform Ln:CaWO₄ (Ln = Eu, Dy) Nanophosphors with Multicolor Luminescence for Optical and CT Imaging

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Microemulsion-based synthesis and luminescence of nanoparticulate CaWO4, ZnWO4, CaWO4:Tb, and CaWO4:Eu

Cited by 50 publications

References 39 publications

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

Synthesis and Luminescence Properties of Tb3+-Doped K2BaW2O8 Phosphors

Block Copolymer-Encapsulated CaWO4 Nanoparticles: Synthesis, Formulation, and Characterization

Microemulsion‐Mediated Synthesis and Properties of Uniform Ln:CaWO4 (Ln = Eu, Dy) Nanophosphors with Multicolor Luminescence for Optical and CT Imaging

Contact Info

Product

Resources

About

Block Copolymer-Encapsulated CaWO₄ Nanoparticles: Synthesis, Formulation, and Characterization

Microemulsion‐Mediated Synthesis and Properties of Uniform Ln:CaWO₄ (Ln = Eu, Dy) Nanophosphors with Multicolor Luminescence for Optical and CT Imaging