Author
Christopher B. Murray
Other affiliations: Universal Display Corporation, Lawrence Berkeley National Laboratory, University of Chicago ...read more
Bio: Christopher B. Murray is an academic researcher from University of Pennsylvania. The author has contributed to research in topics: Nanocrystal & Quantum dot. The author has an hindex of 88, co-authored 336 publications receiving 54410 citations. Previous affiliations of Christopher B. Murray include Universal Display Corporation & Lawrence Berkeley National Laboratory.
Topics: Nanocrystal, Quantum dot, Nanoparticle, Nanorod, Materials science
Papers published on a yearly basis
Papers
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TL;DR: In this article, a theory of the electronic-structure and excitonic absorption spectra of PbS and PbSe nanowires and nanorods in the framework of a four-band effective mass model is presented.
Abstract: A theory of the electronic-structure and excitonic absorption spectra of PbS and PbSe nanowires and nanorods in the framework of a four-band effective-mass model is presented. Calculations conducted for PbSe show that dielectric contrast dramatically strengthens the exciton binding in narrow nanowires and nanorods. However, the self-interaction energies of the electron and hole nearly cancel the Coulomb binding, and as a result the optical absorption spectra are practically unaffected by the strong dielectric contrast between PbSe and the surrounding medium. Measurements of the size-dependent absorption spectra of colloidal PbSe nanorods are also presented. Using room-temperature energy-band parameters extracted from the optical spectra of spherical PbSe nanocrystals, the theory provides good quantitative agreement with the measured spectra.
132 citations
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TL;DR: The template-based coassembly scheme utilized here for plasmonic coupling offers a versatile platform for improving the understanding of optical interactions among individual chemically prepared nanocrystal components.
Abstract: We demonstrate plasmonic enhancement of upconversion luminescence in individual nanocrystal heterodimers formed by template-assisted self-assembly. Lithographically defined, shape-selective templates were used to deterministically coassemble single Au nanorods in proximity to single hexagonal (β-phase) NaYF4:Yb3+,Er3+ upconversion nanophosphors. By tailoring the dimensions of the rods to spectrally tune their longitudinal surface plasmon resonance to match the 977 nm excitation wavelength of the phosphors and by spatially localizing the phosphors in the intense near-fields surrounding the rod tips, several-fold luminescence enhancements were achieved. The enhancement effects exhibited a strong dependence on the excitation light’s polarization relative to the rod axis. In addition, greater enhancement was observed at lower excitation power densities due to the nonlinear behavior of the upconversion process. The template-based coassembly scheme utilized here for plasmonic coupling offers a versatile platfor...
129 citations
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TL;DR: In this paper, the authors present a rapid and efficient synthesis of metallic gold and silver nanoparticles using ascorbic acid (vitamin C), which acts both as reducing and stabilizing agent.
Abstract: In this study, we present a rapid and efficient synthesis of metallic gold and silver nanoparticles using ascorbic acid (vitamin C), which acts both as reducing and stabilizing agent. The size of the particles obtained, in the range of 8 to 80 nm for gold and 20 to 175 nm for silver, and their polydispersity (10–50%) are subtly affected, therefore tunable, by the pH of either the metal salt solution or the ascorbic acid solution. We also show that one of the main features of this synthetic approach is the simple, fast and versatile nanoparticle surface modification with a large variety of water soluble surfactants that can be neutral, positively or negatively charged.
126 citations
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TL;DR: The carbon supported nanorods have comparable activity but are remarkably more stable than conventional Pt catalysts for the oxygen reduction reaction in alkaline environments.
Abstract: Low temperature fuel cells are clean, effective alternative fuel conversion technology. Oxygen reduction reaction (ORR) at the fuel cell cathode has required Pt as the electrocatalyst for high activity and selectivity of the four-electron reaction pathway. Targeting a less expensive, earth abundant alternative, we have developed the synthesis of cobalt phosphide (Co2P) nanorods for ORR. Characterization techniques that include total X-ray scattering and extended X-ray absorption fine structure revealed a deviation of the nanorods from bulk crystal structure with a contraction along the b orthorhombic lattice parameter. The carbon supported nanorods have comparable activity but are remarkably more stable than conventional Pt catalysts for the oxygen reduction reaction in alkaline environments.
123 citations
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Air Force Research Laboratory1, University of Alberta2, Purdue University3, Boston University4, University of Pennsylvania5, University of Salford6, City University of New York7, Heriot-Watt University8, Vanderbilt University9, University of Michigan10, Stanford University11, University of Texas at Austin12, State University of New York System13, Norfolk State University14, University of Southampton15, University of Chicago16, University of Warsaw17, University of Maryland, College Park18, Towson University19, University of Central Florida20
TL;DR: This roadmap is an effort to present emerging fronts in areas of optical metamaterials that could contribute and apply to other research communities by anchoring each contribution in current work and prospectively discussing future potential and directions.
Abstract: Optical metamaterials have redefined how we understand light in notable ways: from strong response to optical magnetic fields, negative refraction, fast and slow light propagation in zero index and trapping structures, to flat, thin and perfect lenses. Many rules of thumb regarding optics, such as mu = 1, now have an exception, and basic formulas, such as the Fresnel equations, have been expanded. The field of metamaterials has developed strongly over the past two decades. Leveraging structured materials systems to generate tailored response to a stimulus, it has grown to encompass research in optics, electromagnetics, acoustics and, increasingly, novel hybrid materials responses. This roadmap is an effort to present emerging fronts in areas of optical metamaterials that could contribute and apply to other research communities. By anchoring each contribution in current work and prospectively discussing future potential and directions, the authors are translating the work of the field in selected areas to a wider community and offering an incentive for outside researchers to engage our community where solid links do not already exist.
120 citations
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
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TL;DR: In this article, the authors focus on the properties of quantum dots and their ability to join the dots into complex assemblies creates many opportunities for scientific discovery, such as the ability of joining the dots to complex assemblies.
Abstract: Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.
10,737 citations
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9,432 citations
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7,711 citations
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TL;DR: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection and these nanometer-sized conjugates are water-soluble and biocompatible.
Abstract: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection. In comparison with organic dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-soluble and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomolecules recognized specific antibodies or antigens.
7,393 citations