Synthesis and Upconversion Luminescence of Hexagonal‐Phase NaYF<sub>4</sub>:Yb, Er<sup>3+</sup> Phosphors of Controlled Size and Morphology

Zeng, Jinghui; Su, Jingtan; Li, Zhihua; Yan, Ruoxue; Li, Yadong

doi:10.1002/adma.200402046

Cited by 551 publications

(369 citation statements)

References 25 publications

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“…The hexagonal phase of NaYF 4 (β-NaYF 4 ) is one of the best host materials for upconversion due to its low phonon energies (27), being several orders of magnitude more efficient than the cubic, α-NaYF 4 phase (28). Several chemical approaches including coprecipitation (29) and hydrothermal synthesis (30) have been employed to synthesize β-NaYF 4 -based UCNPs. However coprecipitation methods usually necessitate postsynthesis treatments to improve crystallinity of the products, and hydrothermal approaches typically involve long reaction times (ranging from a few hours up to several days) in pressurized reactors (e.g., autoclaves).…”

mentioning

confidence: 99%

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Collins

Kang

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

421

376

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We report a one-pot chemical approach for the synthesis of highly monodisperse colloidal nanophosphors displaying bright upconversion luminescence under 980 nm excitation. This general method optimizes the synthesis with initial heating rates up to 100°C∕ minute generating a rich family of nanoscale building blocks with distinct morphologies (spheres, rods, hexagonal prisms, and plates) and upconversion emission tunable through the choice of rare earth dopants. Furthermore, we employ an interfacial assembly strategy to organize these nanocrystals (NCs) into superlattices over multiple length scales facilitating the NC characterization and enabling systematic studies of shape-directed assembly. The global and local ordering of these superstructures is programmed by the precise engineering of individual NC's size and shape. This dramatically improved nanophosphor synthesis together with insights from shape-directed assembly will advance the investigation of an array of emerging biological and energy-related nanophosphor applications.doped nanocrystals | superlattice | lanthanides | luminescence R ecent advances in synthesis and controlled assembly of monodisperse colloidal nanocrystals (NCs) into superlattice structures have enabled their applications in optics (1), electronics (2), magnetic storage (3), etc. Single-and multicomponent superlattices composed of spherical NCs are increasingly studied and a rich family of structures is now accessible (4, 5), where the electronic and magnetic interactions between the constituents gives rise to new cooperative properties (6, 7). New synthetic approaches are yielding nonspherical NCs with physical properties unobtainable by simply tuning the size of the spheres (8-11), providing an even broader array of nanoscale building blocks. The size and shape dependence of NC's biological activity (12, 13) and toxicity (14) is also of intense interest. However, the challenge of precisely controlling particle shape while maintaining uniformity in size and surface functionality has limited studies of NC environmental health and safety just as it has hindered efforts to organize anisotropic building blocks and to establish methods to capture their unique properties in NC superlattice thin films.Lanthanide-doped nanophosphors are an emerging class of optical materials (15). These NCs often possess "peculiar" optical properties [e.g., quantum cutting (16) and photon upconversion (17)], allowing the management of photons that could benefit a variety of areas including biomedical imaging (18, 19) and therapy (20), photovoltaics (16, 21), solid state lighting (22), and display technologies (23). Colloidal upconversion nanophosphors (UCNPs) are capable of converting long-wavelength near-infrared excitation into short-wavelength visible emission through the long-lived, metastable excited states of the lanthanide dopants (24). In contrast to the Stokes-shifted emissions from semiconductor NCs or organic fluorophores and the multiphoton process employing fluorescent dyes, UCNPs offer several ...

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mentioning

confidence: 99%

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Collins

Kang

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

421

376

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“…[19][20][21] However, most of these nanoparticles are synthesized at high temperatures. 22,23 In recent years, a hydrothermal synthesis method at lower temperature has been found. 24 Different constitutions of nanoparticles have various upconverting effects.…”

Section: Results and Discussion Characters Of The Ucnps-curcuminmentioning

confidence: 99%

Upconversion nanoparticles conjugated with curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in lung under near infrared light

Ye¹,

Li²,

Fang³

2014

IJN

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Curcumin has phototoxic effects on bacteria under <450 nm irradiation, but it is unstable in vivo and cannot exert effects on deep tissues. Near infrared light (NIR) is harmless to the body and has stronger penetration than visible light. In order to improve the effects of curcumin, upconversion nanoparticles conjugated with curcumin (UCNPs-curcumin) are designed to upconvert NIR to the excitation wavelength of curcumin. UCNPs-curcumin were synthesized using polyethyleneimine to combine curcumin and UCNPs, based on typical composition of lanthanide nitrates Re(NO) 3 (Y:Yb:Er=78%:20%:2%) linked by ethylenediaminetetraacetic acid in sodium fluoride (NaF) matrix, to upconvert NIR to 432 nm light. The product was characterized by size distribution, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Growth inhibition of methicillin-resistant Staphylococcus aureus (MRSA) was not only measured in vitro but also investigated on MRSA-induced pneumonia in mice. The results showed that curcumin was covered by UCNPs to form stable nanoparticles whose average size was 179.5 nm and zeta potential was −33.7 mV in normal saline. The UCNPs-curcumin produced singlet oxygen, which reaches a stable level after 30 minutes of irradiation, and took effect on MRSA through bacterial cytoplasm leakage. They alleviated MRSA-induced pneumonia and reduced bacterial counts in lungs with 980 nm irradiation (0.5 W/cm 2 ) on chests of mice. It is confirmed that the UCNPs-curcumin in lungs are activated under NIR irradiation and strengthen their antibacterial effects on MRSA. This research provides a new type of NIR photosensitizer, which plays an important role in phototoxic effects of curcumin in deep tissues under NIR.

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“…1). I n o r d e r t o o b t a i n t h e U C N P s w i t h g o o d biocompatibility, "one step" method was developed in recent years with the help of hydrophilic or binary cooperative ligands, such as polyols [10,35,36], EDTA [37][38][39][40], citrate [37,[41][42][43][44][45], sodium dodecyl sulfate (SDS) [46], PVP [47], small-molecule binary acid [48,49], polyethylene glycol (PEG) [49], PVP [50], PAA [51,52], PEI [51], 3-mercaptopropionic acid (3MA) and 6-aminocaproic acid (6AA) [53] etc. This "one step" method has the advantages of high efficiency and could be operated at mild reaction conditions [54,55].…”

Section: Synthesis Of Rare Earth Doped Ucnpsmentioning

confidence: 99%

Up-Conversion Nanoparticles for Gastric Cancer Targeted Imaging and Therapy

Yang¹,

Han²,

Yue³

2016

Nano BioMed ENG

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As a new generation of fluorophores, up-conversion nanoparticles (UCNPs) exhibit high penetration depth in tissues, low photodamage to biological samples, large Stokes shifts, sharp emission bands, free auto-fluorescence background and high photostability, thus making them an ideal kind of fluorescent labels for a variety of assay formats ranging from bio-imaging to cancer therapy. In this article, the method for the synthesis of biocompatible UCNPs, the recent progress regarding the UCNPs for multimodal targeted tumor imaging, drug delivery, photodynamic therapy (PDT), and photothermal therapy (PTT) are discussed on emphasis. The challenges and opportunities in this emerging field are also presented.

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Synthesis and Upconversion Luminescence of Hexagonal‐Phase NaYF₄:Yb, Er³⁺ Phosphors of Controlled Size and Morphology

Cited by 551 publications

References 25 publications

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Upconversion nanoparticles conjugated with curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in lung under near infrared light

Up-Conversion Nanoparticles for Gastric Cancer Targeted Imaging and Therapy

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Synthesis and Upconversion Luminescence of Hexagonal‐Phase NaYF4:Yb, Er3+ Phosphors of Controlled Size and Morphology

Cited by 551 publications

References 25 publications

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly

Upconversion nanoparticles conjugated with&nbsp;curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in&nbsp;lung&nbsp;under near infrared light

Up-Conversion Nanoparticles for Gastric Cancer Targeted Imaging and Therapy

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Synthesis and Upconversion Luminescence of Hexagonal‐Phase NaYF₄:Yb, Er³⁺ Phosphors of Controlled Size and Morphology

Upconversion nanoparticles conjugated with curcumin as a photosensitizer to inhibit methicillin-resistant Staphylococcus aureus in lung under near infrared light