Author
Nathan S. Lewis
Other affiliations: Lawrence Berkeley National Laboratory, Massachusetts Institute of Technology, Carnegie Institution for Science ...read more
Bio: Nathan S. Lewis is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Semiconductor & Silicon. The author has an hindex of 112, co-authored 720 publications receiving 64808 citations. Previous affiliations of Nathan S. Lewis include Lawrence Berkeley National Laboratory & Massachusetts Institute of Technology.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the currentvoltage and spectral response properties of polycrystalline n-GaAs photoanodes in contact with aqueous KOH-Se/sup -2/-/ and nonaqueous CH/sub 3/CN-ferrocene/sup +/0/-LiClO/sub 4/ electrolytes were determined.
Abstract: Current-voltage and spectral response properties were determined for polycrystalline n-GaAs photoanodes in contact with aqueous KOH-Se/sup -2/-/ and nonaqueous CH/sub 3/CN-ferrocene/sup +/0/-LiClO/sub 4/ electrolytes. The n-GaAs/KOH-Se/sup -/2-/ system initially exhibited poor junction behavior, but chemisorption of Ru/sup III/, Rh/sup III/, Ir/sup III/, Co/sup III/, or Os/sup III/ ions onto the GaAs photoanode was found to yield improved I-V properties. The trend in I-V improvement correlated with improved electrocatalysis of Se/sup 2/minus// oxidation at p-GaAs, N/sup +/-GaAs, and In/sub 2/O/sub 3/ electrode surfaces. The n-GaAs/CH/sub 3/CH system displayed excellent junction behavior and did not respond to metal chemisorption treatments. These results are consistent with the metal-ion-induced improvements being predominantly due to electrocatalytic effects.
TL;DR: In this article, the binding of CO 2 to metal macrocycles has been determined electrochemically by using cyclic voltammetry or differential pulse polarography, and the binding constants, K for a series of Co(I) tetraammacrocycle complexes in (CH3)_2SO showed a strong correlation with the Co(II/I) redox potential.
Abstract: The binding of CO_2 to metal macrocycles has been determined electrochemically by using cyclic voltammetry or differential pulse polarography. The CO_2 binding constants, K for a series of Co(I) tetraammacrocycle complexes in (CH3)_2SO showed a strong correlation with the Co(II/I) redox potential. Although meso and d,l stereoisomers of [Co^I(Me_6[14]4,11- diene)]^+ had identical redox potentials, K_(CO_)2 differed by a factor of 10^2 for these stereoisomers, suggesting a large steric effect on CO_2 binding. Binding of CO_2 to Ni(I) tetraazamacrocycles in (CH_3)_2SO yielded a redox potential dependence similar to that of Co(I) macrocycles. A weak correlation between K_(CO_2) and the solvent dielectric constant was found for d,l-[Co(Me_6[ 14]-4,11 -diene)]^+. In tetrahydrofuran (THF), d,l-[CO(Me_6[14]4,11-diene)]^+ was found to bind CO_2 more strongly in the presence of 0.1 M Li^+ than in the presence of 0.1 M tetrabutylammonium (TBA^+). Electrochemically determined K_(CO_2)'s for Co(salen)^- and Co(Me_2salen)^- in THF indicated a strong dependence on redox potential and electrolyte cation.
TL;DR: In this article, the reactivity of n-GaAs surfaces with transition-metal complexes has been studied and shown to increase carrier trapping rates. But little information is available regarding the chemistry of these surface treatments.
Abstract: The authors report studies of the reactivity of n-GaAs surfaces with transition-metal complexes. Generally, adsorption of metal ions at semiconductor junctions has been observed to increase carrier trapping rates. A notable exception is the improved performance of n-GaAs interfaces after exposure to acidic aqueous solutions of Ru(III) ions and other metal cations, but little information is available regarding the chemistry of these surface treatments. Except for systems in which metal ions act as precursors for the deposition of metals or metal alloys, no information is available regarding the oxidation state or chemical environment of chemisorbed transition-metal complexes on semiconductor electrodes. Possible but undocumented mechanisms of metal ion attachment to the semiconductor surface include electrostatic binding, ligand substitution processes, and redox reactions. To explore the various possible modes of reaction, they have investigated the chemistry of n-GaAs surfaces in contact with aqueous solutions of Co(III) complexes.
26 Mar 2014
TL;DR: In this article, an artificial photosynthetic system that utilizes sunlight and water as the inputs and produces hydrogen and oxygen as the outputs is developed. But the system is not suitable for indoor use.
Abstract: We are developing an artificial photosynthetic system that will utilize sunlight and water as the inputs and produce
hydrogen and oxygen as the outputs We are taking a modular, parallel development approach in which three distinct primary
components- the photoanode, the photocathode, and the product- sepg but ion- conducting membrane- are fabricated and
optimized sep before assembly into a complete water- splitting system The design principles incorporate two sep,
photosensitive semiconductor /liq junctions that will collectively generate the 17- 19 V at open circuit necessary to support both
the oxidn of H_2O (or OH-) and the redn of H+ (or H_2O) The photoanode and photocathode will consist of rod- like
semiconductor components, with attached heterogeneous multi- electron transfer catalysts, which are needed to drive the oxidn
or redn reactions at low overpotentials The high aspect- ratio semiconductor rod electrode architecture allows for the use of
low cost, earth abundant materials without sacrificing energy conversion efficiency due to the orthogonalization of light
absorption and charge- carrier collection Addnl, the high surface- area design of the rod- based semiconductor array electrode
inherently lowers the flux of charge carriers over the rod array surface relative to the projected geometric surface of the
photoelectrode, thus lowering the photocurrent d at the solid /liq junction and thereby relaxing the demands on the activity
(and cost) of any electrocatalysts A flexible composite polymer film will allow for electron and ion conduction between the
photoanode and photocathode while simultaneously preventing mixing of the gaseous products Sep polymeric materials will
be used to make elec contact between the anode and cathode, and also to provide structural support Interspersed patches of
an ion conducting polymer will maintain charge balance between the two half- cells
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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.
Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …
33,785 citations
TL;DR: In this article, the authors describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency.
Abstract: THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-µm-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.
26,457 citations
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
9,432 citations
TL;DR: This critical review shows the basis of photocatalytic water splitting and experimental points, and surveys heterogeneous photocatalyst materials for water splitting into H2 and O2, and H2 or O2 evolution from an aqueous solution containing a sacrificial reagent.
Abstract: This critical review shows the basis of photocatalytic water splitting and experimental points, and surveys heterogeneous photocatalyst materials for water splitting into H2 and O2, and H2 or O2 evolution from an aqueous solution containing a sacrificial reagent Many oxides consisting of metal cations with d0 and d10 configurations, metal (oxy)sulfide and metal (oxy)nitride photocatalysts have been reported, especially during the latest decade The fruitful photocatalyst library gives important information on factors affecting photocatalytic performances and design of new materials Photocatalytic water splitting and H2 evolution using abundant compounds as electron donors are expected to contribute to construction of a clean and simple system for solar hydrogen production, and a solution of global energy and environmental issues in the future (361 references)
8,850 citations