Synthesis of K2Se solar cell dopant in liquid NH3 by solvated electron transfer to elemental selenium

This study explores the rich chemistry of elemental selenium reduction to monoselenide anions. The simplest possible homogeneous electron transfer occurs with free electrons, which is only possible in plasmas; however, alkali metals in liquid ammonia can supply unbound electrons at much lower temperatures, allowing in situ analysis. Here, solvated electrons reduce elemental selenium to K2Se, a compound relevant for alkali metal doping of Cu(In,Ga)Se2 solar cell material. It is proposed that the reaction follows pseudo first-order kinetics with an inner-sphere or outer-sphere oxidation semi reaction mechanism depending on the concentration of solvated electrons

Electrodeposition of In2S3 buffer layer for Cu(In,Ga)Se2 solar cells

AbstractThe electrochemical deposition of In2S3 thin films was carried out from an aqueous solution of InCl3 and Na2S2O3. The effect of the potential of deposition was studied on the cell parameters of CIGSe based solar cells. The obtained films depending on the deposition potential and thickness exhibited complete substrate coverage or nanocolumnar layers. XPS measurements detected the presence of indium sulphide and hydroxide depending on the deposition parameters. Maximum photoelectric conversion efficiency of 10.2% was obtained, limited mainly by a low fill factor (56%). Further process optimization is expected to lead to efficiencies comparable to CdS buffer layers

Las tres brechas del desarrollo sostenible y el cierre de la brecha ambiental en Chile: oportunidades para una recuperación pospandemia más sostenible y con bajas emisiones de carbono en América Latina y el Caribe

Las tres crisis del sistema internacional se expresan en tres brechas desde la perspectiva de la periferia latinoamericana y caribeña: la brecha del bajo crecimiento, la brecha de la desigualdad y la brecha de la destrucción del ambiente, en economías que dependen de las exportaciones de recursos naturales para sostener el crecimiento. En este documento se utiliza el concepto de “límites planetarios” para analizar la brecha ambiental en Chile. Estos se definen a partir de parámetros que circunscriben un área dentro de la cual los procesos biofísicos se mantienen en condiciones relativamente estables. El objetivo de definir dichos límites ambientales es lograr que la humanidad pueda operar sin alterar de manera drástica el estado del sistema terrestre, a fin de mantener la condición de habitabilidad del planeta y su resiliencia, así como el bienestar humano.Introducción .-- I. Antecedentes. A. Definición y relevancia del concepto de límites ambientales planetarios. B. La relevancia de analizar los límites ambientales planetariosa nivel nacional. C. Brechas en identificación de límites ambientales a niveles globales y nacional .-- II. Selección de límites: el caso de Chile .-- III. Una nueva forma de crecimiento .-- IV. Los límites planetarios y el modelo de las tres brechas .-- V. Brechas de conocimiento y recomendaciones de política pública .-- VI. Conclusiones

Peptide immobilisation on porous silicon surface for metal ions detection

In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis) peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization

Dissertatio theologica de descriptione & attributis Dei quam ... præside Jordano Edenio ... publicè defendendam suscipit, Uno Joannis Terserus. In aud. Gust. die 17 Decembr. anno 1664, horis ante meridiem ord.

This study explores the rich chemistry of elemental selenium reduction to monoselenide anions. The simplest possible homogeneous electron transfer occurs with free electrons, which is only possible in plasmas; however, alkali metals in liquid ammonia can supply unbound electrons at much lower temperatures, allowing in situ analysis. Here, solvated electrons reduce elemental selenium to K2Se, a compound relevant for alkali metal doping of Cu(In,Ga)Se2 solar cell material. It is proposed that the reaction follows pseudo first-order kinetics with an inner-sphere or outer-sphere oxidation semi reaction mechanism depending on the concentration of solvated electrons. Keywords: Solvated electron, Liquid ammonia, Microelectrode, Alkali metal selenide extrinsic doping, Chalcopyrite, Copper indium gallium diselenid

Growth of Phosphazene Film Onto Undoped n-InP

International audienc

Electrochemistry at capped platinum nanoparticle Langmuir Blodgett films: A study of the influence of platinum amount and of number of LB layers

International audiencePlatinum nanoparticles (n-Pt), over-grafted with 2-thiophenecarbonyl chloride are assembled on gold electrodes, by the Langmuir Blodgett (LB) technique using behenic acid (BHA) as promoting agent. These layers are electrochemically active without any preliminary activation. The [Fe(CN)6]3−/4− redox couple was used as electrochemical probe. This paper reports on the influence of the number of deposited LB layers, and the n-Pt density on the electrochemical response. n-Pt density was modified by the change of the “BHA/n-Pt” ratio. Cyclic voltammograms of “[Fe(CN)6]3−/4−” were observed whatever the coating conditions. As soon as the first layer was deposited the electrochemical response was associated to the n-Pt coverage, its response slightly increased up to a steady state for five or seven layers. As expected, the increase of the Pt density favored the increase of the current density. XPS analysis performed before and after electrochemical cycling showed that 4-mercaptoaniline capped platinum nanoparticles, and their over grafting were chemically and electrochemically stable. Analysis of influence of the number or the n-Pt density of the layers showed that the electrochemically active part of LB electrodes was provided by the last layer plus a part of the underlying one