The photoelectrochemistry of and in polysulfide electrolyte is studied with particular emphasis on the pretreatments of the electrodes and on their output stability. The use of Cd doping, (photoelectro)chemical etching, and mild air oxidation all were found to improve electrode performance. The effect of air oxidation was reproducible only for the diselenide, where it improved the fill factor and, because of a negative shift of the flatband potential, the open‐circuit voltage. Optimized cells showed, at elevated temperatures, conversion efficiencies around 5 and 7.5% for the sulfide and selenide, respectively. The positive temperature dependence of the photo‐I‐V characteristics at both low and high illumination intensities, the existence of optimal polysulfide solution compositions, the linear dependence of the photocurrent on the light intensity, and the effects of temperature, solution composition, and initial current density on the photocurrent decrease during the first minute of operation of the cells, are ascribed to limitations of the charge‐transfer process across the solid/liquid interface. Thermally activated rates of ad‐ and desorption of sulfur containing solution species on the semiconductor surface and/or the presence of adsorption‐induced electronic states in the bandgap are postulated as causes for this behavior. Notwithstanding these limitations the cells are resistant to photocorrosion, after the initial decrease is arrested, in contrast to what is known for similar Cd‐chalcogenide‐based systems. We suggest that this stability, which persists under load and at high light intensities, is due to the strength and character of the bonds in , or to the presence of a top layer of indium oxide in which recombination will take place, or to both.

AbstractEs werden unterschiedliche Oberflächenbehandlungen an den Titel‐Photoelektroden durchgeführt, wie z.B. Cd‐Dotierung, chemisches Ätzen, milde Luftoxidation, die zeigen, daß diese Chalkogenide äußerst sensitiv gegenüber solchen Oberflächenveränderungen sind.

AbstractBei Culnsz‐Proben mit geringem Energieumwandlungswirkungsgrad (2%) wird eine relativ heterogene Oberfläche gefunden, die teilweise stark mit In angereichert ist.

The photoelectrochemical properties of the ternary semiconductor is further investigated. Photoelectrochemical etching increases the photocurrent of this material by an order of magnitude in various electrolytes. Cyclic voltametry, Auger analyses, and thermodynamic calculations suggest that oxide is unlikely to be produced during photoetching. Degradation of the photocurrent with time in polysulfide electrolyte due to photocorrosion is studied with x‐ray photoelectron spectroscopy (XPS). Thermodynamic and solid‐state data are used for the construction of the band diagram of system. It is shown that the time behavior of this system resembles that of photoelectrochemical cell.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTernary chalcogenide-based photoelectrochemical cells. 6. Is there a thermodynamic explanation for the output stability of copper indium sulfide (CuInS2) and copper indium selenide (CuInSe2) photoanodes?David Cahen and Yehudith MirovskyCite this: J. Phys. Chem. 1985, 89, 13, 2818–2827Publication Date (Print):June 1, 1985Publication History Published online1 May 2002Published inissue 1 June 1985https://pubs.acs.org/doi/10.1021/j100259a023https://doi.org/10.1021/j100259a023research-articleACS PublicationsRequest reuse permissionsArticle Views666Altmetric-Citations37LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

AbstractIn verschiedenen Elektrolyten verstärkt photoelektrochemisches Ätzen den Photostrom des ternären Halbleiters CdIn2Se4 um eine Größenordnung.

n-CuInSe2, n-CuInS2 and n-CuIn5S8 were used as photoanodes in electrochemical photovoltaic solar cells, using aqueous polysulfide electrolyte. CuIn5S8 was found to be less stable than CuInS2. Because of kinetic limitations of polysulfide-based systems, the CuInSe2/aqueous polyiodide cell was studied and optimized to yield stable, near 12% AM1 conversion efficiency. The strategy used to achieve this is described. (Photo)electrochemical methods were used to characterize the semiconductor materials and a photoelectrochemical test was developed to gauge the photovoltaic activity of p-CuInSe2 layers used in solid state cells. Solid-state chemical studies on the (Cu2X)2-(In2X3)(X=S,Se) system, and the use of photoelectrochemistry in them, are briefly described.

The performance of photoelectrochemical cells, containingn-CuInX2 (X=S, Se) semiconductor electrodes, has been studied as a function of solution composition and temperature. Significant differences with cells using CdSe or CdIn2Se4 electrodes are found, also in terms of output stability. These results, together with surface analyses, suggest the occurrence of binary chalcogenides on the electrode surfaces, which seems to influence the behaviour of these cells favourably

The stability and relative quantum yields of n-CdSe/polysulfide photoelectrochemical cells under different applied potentials, light intensities and electrolyte concentrations, and after different photoelectrode surface preparation techniques, were investigated. It was deduced that the availability at the electrode surface of polysulfide ions, which serve as hole acceptors, decreases with forward bias. On the other hand, the flow of the photogenerated holes towards the surface of the semiconductor is affected to a lesser extent by increasing (forward) bias up to the point of maximum power, beyond which the hole flux drops sharply with the bias. Consequently, the polarization of the cell (as given by the ratio between the peak and the steady-state photocurrents) is maximal near the point of maximum power and there the stability is lowest at moderate light intensities (ca. AM1). Under strong illumination, depletion of the polysulfide ions from the surface of the electrode due to photooxidation, together with increasing sulfur to sulfide ratio at the surface, leads to considerable band flattening (decrease in the flat-band potential), and consequently electrodes under forward bias show considerably smaller photocurrents and thus greater stability than electrodes under short-circuit (and reverse bias) conditions (at constant illumination). Increasing the surface area of the electrode by photoetching or increasing the concentration of the electrolyte leads to the behavior which is observed under moderate light intensities, which shows the interdependency of all these factors.

We report that n-type single crystals of n-CuInSe2 in aqueous polysulfide solution exhibit high quantum efficiencies of 0.8–0.9 in the wavelength region between 600–1150 nm when used as photoanodes in photoelectrochemical cells. Photocurrents of 28 mA/cm2 were measured on a ’’winter’’ day in Rehovot (71 mW/cm2) which corresponds to 40 mA/cm2 under AM1 (Air Mass 1) conditions (100-mW/cm2 sunlight). Stability tests of n-CuInSe2 photoanodes (20 000-C/cm2 photocharge passage) at short circuit current densities of 40 mA/cm2 have shown no deterioration whatsoever of the measured photocurrents.

AbstractDie untersuchte Zelle enthielt n‐CdIn2Se4 (ein crosssubstitutional‐Analogon von CdSe mit unvollständigem Kationengitter) als Photoelektrode und eine wäßrige Lösung von je 2 M KOH, Sund Na2S als Elektrolyt.

Electrodes of n-CdSe0.65Te0.35 were prepared either by electroplating or by pasting of a slurry of the semiconductor. Analyses of spectral response measurements indicate that the high quantum efficiencies we obtained are probably due to the rather low doping of about 1015 cm-3. Diffusion lengths were found to be 0.1–0.5 μm, a result that is reflected in the moderate open-circuit voltages and fill factors obtained. Scanning electron microscopy shows very different morphologies for electrodes prepared by the two methods, but they showed similar efficiencies and electronic properties.

is a cross‐substitutional analogue of with an incomplete cation lattice. We have carried out an investigation of the polysulfide photoelectrochemical cell. A selective photoelectrochemical etching of the semiconductor surface leads to a dramatic increase in the photocurrent of the cell (up to 15 mA · cm−2 at small reverse bias) and greatly improved output stability. The spectral response of the cell reveals a considerable sub‐bandgap photocurrent for the etched electrode. This is attributed to excitation via surface states located ∼0.27 eV within the bandgap. After photoetching the electrode, most of the sub‐bandgap response disappears and the response to supra‐bandgap excitation increases by at least an order of magnitude that shows that these surface states serve also as recombination centers or traps for the photogenerated holes. We have analyzed the shape of the spectral response and observed two distinct transition modes: an indirect transition at 1.55 eV and a direct one at 1.72 eV, both of which are within the acceptable range for efficient solar energy conversion. Preliminary results using thin film polycrystalline photoelectrodes of this semiconductor are presented. They show that this material tends to lend itself fairly well to preparation of such electrodes.

CdSe and Cd(Se, Te) alloy layers were electroplated onto titanium substrates from both acid and alkaline baths. When annealed, these layers show good photoelectrode behaviour in a polysulphide electrolyte with high quantum efficiencies and stability. Donor densities are found to be in the range of 1014–1015 cm-3. Scanning electron microscopy studies show the layers to have a very irregular morphology and generally to be composed of elongated spherical particles. Annealing conditions can be chosen such that the layers are of cubic or hexagonal structure.