Nathan S. Lewis

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.

Voltammetry of semiconductor electrodes. 2. Cyclic voltammetry of freely diffusing redox species and rotating semiconductor disk voltammetry

Abstract: A model electrode circuit has been utilized to describe the cyclic voltammetric response of a semiconductor photoelectrode in contact with a freely diffusing reversible redox system. This equivalent circuit formalism also has been used to generate a set of working curves for the steady-state voltammetric behavior of a reversible redox system at a rotating semiconductor disk electrode. The model electrode circuit consisted of an ideal photodiode in series with a metal electrode. The current-voltage solutions have been obtained under varying conditions of illumination, scan rate, or rotation velocity, and the results are presented in a working curve format.

Studies of silicon photoelectrochemical cells under high injection conditions

Abstract: The behavior of Si/CH3OH-dimethylferrocene+/0 junctions has been investigated under high injection conditions. Open circuit voltages of (626±5) mV were obtained at short circuit photocurrent densities of 20 mA/cm^2 for samples with an n + -diffused back region, point contacts on the back surface, and with a base of thickness 390 µm and a 1 ms hole lifetime. The diode quality factor and recombination current density were 1.8±0.1 and (2.6±1.5)×10–8 A/cm^2, respectively. These data are consistent with recombination dominated by the base and back contact regions, and not at the Si/CH3OH interface.

Studies of polycrystalline n-GaAs junctions: effects of metal ion chemisorption on the photoelectrochemical properties of n-GaAs/KOH-Se-/2-, n-GaAs/CH3CN-ferrocene+/0, and n-GaAs/Au interfaces

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.

Reaction entropy measurements for transition-metal ions bound to Nafion-coated electrode surfaces

Abstract: Comparaison des potentiels redox, des entropies de reaction et des energies libres differentielles pour les ions metalliques dans les films de Nafion dans le cas des complexes: Fe(bpy) 3 3+/2+ , Ru(bpy) 3 3+/2+ , Co(bpy) 3+/2+ , Ru(NH 3 ) 6 3+/2+ , Ru(NH 3 ) 5 (pyr) 3+/2+ , etc, avec bpy=bipyridine-2,2' et pyr=pyridine. Donnees sur l'influence de l'environnement local autour des sites metalliques sur les mesures de l'entropie des reactions electrochimiques

Light assisted reactions of dinuclear diisocyano ligand bridged complexes

Abstract: A complex ion containing rhodium, Rh 2 (1,3-diisocyanopropane) 4 2+ is called "rhodium bridge." Because of the nature of its molecular structure, it is deep blue in water solution. Irradiation of the blue complex between 500 and 600 nm leads to direct reduction of the protons in water to hydrogen gas. In this reaction rhodium bridge is converted to a yellow form, in which each of the two rhodiums has lost one electron. The H 2 -producing visible photoreaction of rhodium bridge can be utilized in a solar-driven water splitting cycle.

I and i

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 …

A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films

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.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

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。

Heterogeneous photocatalyst materials for water splitting

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)