Upconversion
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. Green Synthesis of Upconverting NaYF4 and NaGdF4 Materials and Energy Levels Determination
An alternative green route using a domestic microwave oven to synthesize NaGdF4:Yb,Tm and NaYF4:Yb,Er was successfully developed. Decreasing dopants concentration increased the β-NaREF4/α-NaREF4 ratio in NaGdF4. The scanning electron microscopy (SEM) images of NaGdF4 showed particles ranging from 500 nm to 1 μm with formation of aggregates up to 100 μm,
J. Braz. Chem. Soc.. Publicado em: 2021-08
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2. Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer
The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hy
J. Braz. Chem. Soc.. Publicado em: 2021-02
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3. Upconversion 3D Printed Composite with Multifunctional Applications for Tissue Engineering and Photodynamic Therapy
Upconversion nanoparticles (UCNPs) are suitable materials for bioapplications due to their ability to emit visible light under near infrared (NIR) excitation, in the biological transparency range. Polycaprolactone(PCL)-based scaffolds are widely used in tissue engineering in combination with inorganic compounds to improve bioactivity and osteoconductive prop
J. Braz. Chem. Soc.. Publicado em: 2020-04
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4. JUDD-OFELT ANALYSIS OF Tb3+ AND UPCONVERSION STUDY IN Yb3+-Tb3+ CO-DOPED CALIBO GLASSES
We report on the study of the spectroscopic properties in Ytterbium-Terbium (Yb3+-Tb3+) co-doped calcium lithium borate (CaLiBO) glasses, with the study’s focus being on the upconversion process. Intensity parameters Ωλ for CaLiBO:Tb3+ are determined by the Judd-Ofelt method to be Ω2 = 15.5 × 10-20 cm2, Ω4 = 1.90 × 10-20 cm2 and Ω6 = 3.69 × 10-20 c
Quím. Nova. Publicado em: 2020-02
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5. The Effect of Hydrothermal Treatment on the Morphologies and Optical Properties of Upconversion NaYF 4:Ln 3+ Crystals
This work deals with the synthesis and characterization of upconversion NaYF4:Ln3+ crystals. Co-precipitation and hydrothermal methods were used to synthesize NaYF4:Ln3+ crystals. The experimental procedures were modified to obtain crystals in the cubic (α) phase, hexagonal (β) phase or a mixture between cubic and hexagonal (α/β) phases. Reaction tempera
J. Braz. Chem. Soc.. Publicado em: 2017-09
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6. An Analytical Solution for Fiber Optic Links with Photonic-Assisted Millimeter Wave Upconversion Due to MZM Nonlinearities
Abstract Photonic-assisted technique employed in the generation of stable and high-purity signals in the millimeter wave band has been investigated using dual-parallel Mach-Zehnder modulator. Indeed, this type of generation performs a high order RF multiplier, whose operation principle steams out from the nonlinear characteristic of the external modulators.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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7. Down- and Up-Conversion Photoluminescence of Carbon-Dots from Brewing Industry Waste: Application in Live Cell-Imaging Experiments
Simple synthetic procedures have been applied to obtain luminescent carbon quantum dots, also referred as C-dots, from an abundant carbon source, that is, from the brewing industry waste. The synthetic procedures have been conducted aiming to investigate the effects of the oxidation stage on the properties of the nanomaterial. C-dots down- and up-conversion
J. Braz. Chem. Soc.. Publicado em: 2015-12
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8. Optically Detected Thermal Effects in Rare-Earth Doped Materials for Host Characterization, Thermometric Devices, Nanothermometry and Biothermometry
We present a review of recent works on optically investigated thermal effects in crystalline and amorphous materials doped with trivalent rare-earth (RE) ions. The paper describes how the frequency upconversion (UC) photoluminescence (PL) technique is used to investigate the thermal behavior of samples and how to perform optical measurements of temperature.
J. Braz. Chem. Soc.. Publicado em: 2015-12
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9. Estudos estruturais e espectroscópicos de materiais vitrocerâmicos à base de SiO2-Ta2O5 dopados com Er3+ luminescentes nas regiões do visível e infravermelho próximo / Structural and spectroscopic studies of visible and near-infrared emitting glass ceramic materials based on Er3+- doped SiO2-Ta2O5
Neste trabalho foram realizadas preparação e caracterizações estrutural e espectroscópica de materiais à base de óxidos nanoestruturados de Ta2O5 dispersos em matrizes amorfas de SiO2, dopados com íons Er3+ e Eu3+. Os materiais foram sintetizados através da metodologia sol-gel e caracterizados com o intuito tanto de estudar a estrutura e a distribui
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/07/2012
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10. Laser a base de pó de neodímio com granulação nanométrica / Powder neodymium laser with nanometric granulation
O interesse na pesquisa de Lasers randômicos, meios dispersivos com alto ganho, tem crescido nos últimos anos em virtude das novas possibilidades advindas ao se trabalhar com estes sistemas, como emissões em bandas com baixo ganho, bicromaticidade, localização da luz em meios difusos e sistemas ópticos mais compactos. Nesse trabalho serão discutidos t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/07/2011
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11. Produção e caracterização de vidros de telureto tridopados com íons de terras raras e nanopartículas metálicas para uso em displays coloridos. / Production and characterization of tellurite glasses doped with rare earth ions and metallic nanoparticles for use in color displays.
This works presents studies of the production and the characterization of TeO2 -PbO-GeO2 doped with erbium, thulium and ytterbium ions and also prepared with different metallic nanoparticles for applications in displays. This glass system presents a broad transmission window in the visible and infrared (350 - 6500 nm), high solubility for rare earth ions, lo
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/04/2011
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12. Estudos das propriedade óticas não lineares em meios dopados com absorvedores lentos
Neste trabalho, usando um laser de Ti3+:Safira sintonizado em 803nm como comprimento de onda de excitação, foram realizadas medidas de Z-scan resolvidas no tempo para caracterizar as propriedades óticas não lineares de matrizes vítreas à base de fosfato. Tal matriz denominada PAN (P2O5-Al2O3-Na2CO3) foi dopada com concentrações crescentes de Nd3+, va
Publicado em: 2011