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Showing 1 to 20 of 62 for “"Upconversion"”.
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Quantum information applications of frequency upconversion
We demonstrate the utility of frequency upconversion in a non-linear crystal for quantum information applications. By combining a bright “escort” beam with a signal photon inside of a periodically poled lithium niobate (PPLN) crystal, we are able to achieve near unit conversion efficiency. We use …
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Upconversion luminescence in Er-codoped NaYF4 nanoparticles
… fluoride (NaYF4) represents an exciting class of upconversion nanomaterials (UCNM) which are suitable to bring forward developments in biomedicine and -biodetection. Despite the fact that among various fluoride based upconversion (UC) phosphors lanthanide doped NaYF4 is one of the most studied …
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Upconversion Phosphors for Efficient Solar Energy Harvesting
… NaBiF4:Yb0.18 - 0.20, Er0.005 - 0.04 powders for upconversion of 980nm radiation to UV-Visible emissions. NaYF4:Yb, Tm/Er upconverters were prepared via hydrothermal synthesis where the structure directing agent (citric acid (CA) or trisodium citrate (TC)), NaF concentration (0.4-2.4 M), pH (5-12) …
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Upconversion Nanoparticles for pH Sensing and Imaging
… range of these fluorescers. The ability of upconversion nanoparticles (UCNPs) to overcome these challenges through their unique optical properties (NIR excitation, long lifetimes) motivated this work to further the understanding of interactions between particle and pH dye before applying …
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Anisotropic surface functionalization and applications of upconversion nanoparticles
Lanthanide-doped upconversion nanoparticles (UCNPs) step-wise convert near-infrared adsorbed light into visible emitted light. Monodispersed UCNPs have a large anti-Stokes shift, sharp emission and long excited-state lifetimes. The controlled synthesis of their heterogeneous nanostructures can …
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Metal oxides for efficient infrared to visible upconversion
Upconversion phosphor materials are attracting considerable attention for their possible applications in solar cells with improved efficiency, nanomaterials for bio-imaging, lasers and novel display technologies. Upconversion materials, usually consisting of crystals doped with lanthanide ions, can …
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Strategies for High-Performance Solid-State Photon Upconversion
Photon upconversion, a process that converts multiple low-energy photons into higher energies, has promising applications such as photovoltaics, bio-imaging, and photo-chemistry. Among the techniques capable of achieving photon upconversion, manipulating the excited states of organic molecules is …
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Upconversion quantum yield and luminescence of beta-NaYF4:Yb3+,Er3+ nanoparticles
Lanthanide-based upconversion (UC) nanometer (nm)-sized particles (UCNPs) exhibit the unique ability to emit one higher-energy photon after the sequential absorption of two or more near-infrared (NIR) photons. This UC luminescence (UCL) makes UCNPs very attractive for the use as optical probes in …
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Surface conjugation of upconversion nanoparticles via supramolecular host-guest self-assembly
… applications. Lanthanide (Ln) ions doped upconversion nanoparticle (UCNP) is a good example: while it delivers a great promise as molecular probes, sensors, drug carriers and light transducers for a library of application in the area of biological and physical science. However, the …
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EXPLORING HETEROSTRUCTURED UPCONVERSION NANOPARTICLES: FROM RATIONAL PARTICLE ENGINEERING TO BIOMEDICAL APPLICATIONS
Upconversion nanoparticle (UCNP)-based photodynamic therapy (PDT) with unique anti-stokes luminescence features are of great interest. UCNP-based PDT affords greater tissue penetration depths than that of visible lights and serves as suitable nanoplatforms carrying photosensitizers as well. …
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Single-photon frequency upconversion for long-distance quantum teleportation and communication
… to quantum communication, including frequency upconversion, photon-counting detection, and photon-pair and entanglement generation. We demonstrate a near-unity efficient frequency conversion scheme that allows fast and efficient photon counting at wavelengths in the low-loss fiber optic and …
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Triplet-Triplet Annihilation Upconversion in Solid-State Organic-Inorganic Ureasil Polymer Hosts
Triplet–triplet-annihilation upconversion (TTA-UC) has attracted significant attention as an approach to harvest low energy solar photons that cannot be captured by conventional photovoltaic devices. However, device integration requires the design of solid-state TTA-UC materials that combine high …
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Digital Profiling of Circulating Extracellular Vesicles at Single-Upconversion Nanoparticle Sensitivity and Resolution
… development, bio-conjugation and application of upconversion nanoparticles (UCNPs). In chapter 2, we apply UCNPs for direct enumeration of single CD9 and EpCAM positive EVs (CD9+EpCAM+EVs). The achieved single-molecule sensitivity results in a femtomolar detection limit (1.8 × 106 EVs mL-1), …
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Infrared-to-visible upconversion in hybrid thin films of colloidal nanocrystals and organic molecules
Photon upconversion is a process where two or more low-energy photons are converted into a single higher-energy photon. Upconversion that turns infrared photons into visible ones is particularly useful, having potential applications in photovoltaics, infrared sensing, and biological imaging. In …
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Development of Nanoprobes for the Biological Imaging Using Positive Charged Quantum Dots and Upconversion Nanoparticles
… effect. Semiconductor quantum dots (QDs) or upconversion nanoparticles (UCNPs) exhibit interesting properties such as high photoluminescence, photostability, dual magnetic/optical modality. In this study, biocompatible and stable NPs were developed through the various surface modifications. …
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Design and Synthesis of Photoactive Metal-Organic Frameworks for Photon Upconversion and Energy Transfer Studies
… of 0.002 ± 0.0001. The propensity for photon upconversion through sensitized triplet-triplet annihilation (TTA-UC) was probed in the three anthracene-based MOFs. The MOFs were surface-modified with Pd(II) mesoporphyrin IX (PdMP) as the triplet sensitizer. Upconverted emission from the 9,10-MOF …
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Optical spectroscopy, crystal field analysis, upconversion and energy transfer studies of Er³⁺ doped yttrium vanadate single crystals
… lower lying $\sp4$S$\sb{3/2}$ was studied. The upconversion of red (652.7 nm) and near infrared (799.1 and 979 nm) radiation into green (due to the $\rm{\sp4S\sb{3/2}}\to{\sp4I\sb{5/2}}$ and the thermally populated $\rm{\sp2H\sb{11/12}}\to{\sp4I\sb{15/2}}$ transitions) and red (due to the …
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Optical Processes and Laser Dynamics in Holmium and Neodymium Upconversion -Pumped Visible and Ultraviolet Fluorozirconate Fiber Lasers
Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs
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Thiol-Ene Click Chemistry for Solid State Triplet-Triplet Annihilation Upconversion and Parts-Per-Billion Pyrophosphate Sensing in Artificial Seawater
… media. Chapter I focuses on the synthesis and upconversion performance of rubbery networks fabricated using thiol-ene click photopolymerization. The advancement of triplet-triplet annihilation based upconversion (TTA-UC) in emerging technologies necessitates the development of solid-state …
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Single-photon detection of 1.55 [mu]m entangled light and frequency upconversion in periodically poled lithium niobate for quantum communication
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
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