Relationship between surface morphology and solar conversion efficiency of tungsten diselenide photoanodes

Lewerenz, H. J.; Heller, Adam; DiSalvo, F. J.

doi:10.1021/ja00526a019

Cited by 188 publications

(122 citation statements)

References 3 publications

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“…+ aq [14] Rh photoelectrodeposition was made at −0.2 V (SCE) for 4 min. ; the chronoamperometric deposition profile was monitored until a distinct current decay indicated saturation.…”

Section: Case Studies: Surface Transformationsmentioning

confidence: 99%

Semiconductor Surface Transformations for Photoelectrochemical Energy Conversion

Lewerenz¹

2014

J. Electrochem. Soc.

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The issue of photoelectrode stability, while simultaneously maintaining efficient operation in aqueous solutions, is addressed for energy converting half cells and complete photoelectrocatalytic structures. The historical development of stability concepts, their realization and recent advances are described. Examples are presented that span the time from the inception of photoelectrochemical energy conversion to present day's renewed interest in storable solar energy. The application of (photo)corrosion processes for in-situ synthesis of protective coatings is described and chemical and electronic analyses of the interphases formed are given. Future development and innovation routes will be discussed. The early days of light-induced processes at the solid-electrolyte interface were characterized by a series of fascinating effects. They encompass fundamental investigations of semiconductor-electrolyte junctions, 1,2 the first light-assisted water splitting, 3 photoemission from metals into solution, 4,5 hot electron processes 6,7 and the first carbon dioxide reduction at illuminated semiconductors. 8,9 The conceptual basis of energy conversion at the solid-liquid junction was provided by Gerischer in 1975 when the rectifying nature of the semiconductor-redox electrolyte contact was outlined.1 The elegance of formation of a conformal contact, simply by immersion of the samples into solution, was, however, neutralized by interfacial reactivity that gives rise to photocorrosion. 10,11 In the early assessment of stability of semiconductors at electrolyte junctions, thermodynamic decomposition potentials were introduced and their energy relation relative to the semiconductor band edges was analyzed.10,12 It soon turned out that stability is a predominant and major issue in photoelectrochemical energy conversion in both the photovoltaic and photoelectrocatalytic modes. Early development of stable photoelectrodes, based on the group VIb transition metal dichalcogenides, [13][14][15] which are also characterized by high absorptivity, was compromised by the problem of scalable preparation of efficient electrodes. Technologically advanced semiconductors from the III-V and II-VI groups typically showed rather high conversion efficiencies [16][17][18] but, also, often pronounced photocorrosion.19 A promising approach for stabilization was developed by the Bell Laboratories group where ∼ 10% efficient InP photocathodes had been operated for extended time in aqueous solution. 20The employed conditioning method resulted in the formation of interfacial films 21 that enabled electron transfer but that blocked access of solution components to the absorber surface thereby suppressing the corrosion reactions.In this text, fundamental aspects and recent developments and advances of this method will be outlined and discussed. Basic concepts on stability and photocorrosion are presented first, followed briefly by a discussion of carrier transport across interfacial films. A subsequent section describes the chronological development of ...

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“…+ aq [14] Rh photoelectrodeposition was made at −0.2 V (SCE) for 4 min. ; the chronoamperometric deposition profile was monitored until a distinct current decay indicated saturation.…”

Section: Case Studies: Surface Transformationsmentioning

confidence: 99%

Semiconductor Surface Transformations for Photoelectrochemical Energy Conversion

Lewerenz¹

2014

J. Electrochem. Soc.

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“…This latter option addresses the issue of stability that pertains to most integrated solution-contacted semiconductor structures. Other than TMOs, only a few semiconductors, including the group VI transition metal dichalcogenides [9,10], and oxide-film protected electrodes [11][12][13][14][15][16][17], are stable in aqueous electrolytes.…”

Section: Introductionmentioning

confidence: 99%

Operando Analyses of Solar Fuels Light Absorbers and Catalysts

Lewerenz

Lichterman

Richter

et al. 2016

Electrochimica Acta

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Operando synchrotron radiation photoelectron spectroscopy (SRPES) in the tender X-ray energy range has been used to obtain information on the energy-band relations of semiconductor and metal-covered semiconductor surfaces while in direct contact with aqueous electrolytes under potentiostatic control. The system that was investigated consists of highly doped Si substrates 2 that were conformally coated with ~70 nm titania films produced by atomic-layer deposition.The TiO 2 /electrolyte and the Si/TiO 2 /Ni electrolyte interfaces were then analyzed by synchrotron radiation photoelectron spectroscopy. The PES data provided a determination of the flat-band position and identified regions of applied potential in which Fermi level pinning, depletion, or accumulation conditions occurred. Operando X-ray absorption spectroscopy (XAS) techniques were additionally used to investigate the properties of heterogeneous electrocatalysts for the oxygen-evolution reaction. Operando XAS including the pre-edge, edge and EXAFS regions allowed the development of a detailed picture of the catalysts under operating conditions, and elucidated the changes that in the physical and electronic structure of the catalyst that accompanied increases in the applied potential. Specifically, XAS data, combined with DFT studies, indicated that the activity of the electrocatalyst correlated with the formation of Fe dopant sites in γ-NiOOH.

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“…This is very important for all applications of such systems, for example for the conversion of solar energy (1U, 26,27). It appears that high efficiencies can only be reached -with materials and surfaces where all the effects which favor recombination between electrons and holes can be minimized.…”

Section: Discussionmentioning

confidence: 99%

The Influence of Surface Orientation and Crystal Imperfections on Photoelectrochemical Reactions at Semiconductor Electrodes

Gerischer

1981

ACS Symposium Series

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It is well known that the surface orientation of crystals and imperfections in the surface, like grain boundaries or dislo cations, affect largely the reaction rates at electrodes made of metals or semiconductors. Such effects are most pronounced in those reactions where atoms leave their position in a crystal lat tice or have to be incorporated into such one. These processes are connected with activation barriers which are particularly high for semiconductors where the chemical bonds between the components of the crystal lattice are highly directed and localized. If we con sider photoelectrochemical reactions at semiconductors we have ad ditionally to discuss the influence of these factors on light ab sorption and its consequences. Factors which control the yield of photocurrentsPhotocurrents and photovoltages are induced by the generation of excessive mobile charge carriers. In a semiconductor these are electron hole pairs generated by light absorption. The size of the effects is largely dependent on how far the recombination between electrons and holes can be prevented. An efficient separation of electron hole pairs occurs only in the space charge layer beneath the semiconductor/electrolyte contact. Large efficiencies can be reached if this space charge layer forms a high enough energy bar rier for the two charge carriers to encounter each other. Such a situation is found in a depletion layer of n-type or p-type semi conductors or in an inversion layer (1,2). Here we shall not con sider insulating materials where one can use high external elec tric fields to obtain charge separation (3).Assuming

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Relationship between surface morphology and solar conversion efficiency of tungsten diselenide photoanodes

Cited by 188 publications

References 3 publications

Semiconductor Surface Transformations for Photoelectrochemical Energy Conversion

Semiconductor Surface Transformations for Photoelectrochemical Energy Conversion

Operando Analyses of Solar Fuels Light Absorbers and Catalysts

The Influence of Surface Orientation and Crystal Imperfections on Photoelectrochemical Reactions at Semiconductor Electrodes

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