Determination of flat-band position of cadmium sulfide crystals, films, and powders by photocurrent and impedance techniques, photoredox reaction mediated by intragap states

Finlayson, M. F.; Wheeler, B. L.; Kakuta, Narioyshi; Park, Koon H.; Bard, Allen J.; Campion, Alan; Fox, Marye Anne; Webber, S. E.; White, John

doi:10.1021/j100272a020

Cited by 75 publications

(53 citation statements)

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“…This means that in practice it might be difficult to discern where exactly the rise in absorbance coincides with the potential of the conduction band edge. Figure 11(a) [29,201] that draws on a similar method introduced previously by Bard et al [202][203][204] In Roy's method, the pH dependence of the potential of a platinum electrode immersed in an irradiated suspension of a semiconductor powder (Figure 12) is recorded in the presence of an electron acceptor with pH-independent reduction potential. As an electron acceptor, MV 2+ (methyl viologen; 1,1 -dimethyl-4,4 -bipyridinium dichloride; E MV 2+/+• = −0.45 V versus NHE) [130] is typically used (Figure 12(b)).…”

Section: Cb Vbmentioning

confidence: 99%

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

Beránek

2011

Advances in Physical Chemistry

331

183

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TiO 2 -based nanomaterials play currently a major role in the development of novel photochemical systems and devices. One of the key parameters determining the photoactivity of TiO 2 -based materials is the position of the band edges. Although its knowledge is an important prerequisite for understanding and optimizing the performance of photochemical systems, it has been often rather neglected in recent research, particularly in the field of heterogeneous photocatalysis. This paper provides a concise account of main methods for the determination of the position of the band edges, particularly those suitable for measurements on nanostructured materials. In the first part, a survey of key photophysical and photochemical concepts necessary for understanding the energetics at the semiconductor/solution interface is provided. This is followed by a detailed discussion of several electrochemical, photoelectrochemical, and spectroelectrochemical methods that can be applied for the determination of band edge positions in compact and nanocrystalline thin films, as well as in nanocrystalline powders.

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Section: Cb Vbmentioning

confidence: 99%

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

Beránek

2011

Advances in Physical Chemistry

331

183

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“…have been extensively studied for application in photocatalytic and photoelectrochemical [111,[118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136][137] production of hydrogen. The reason is that they absorb visible light, with the exception of ZnS.…”

Section: Non-oxide Chalcogenidesmentioning

confidence: 99%

“…Also these materials can be synthesized in the form of core-shell nanostructures [114,116,[138][139][140][141][142], which have greater stability. These competing factors fed a lot of research on these semiconductors, both in the past [97][98][99][100][101][102][103][104][105][106][107][108][109][118][119][120][121][122][123][124][125][126][127] and in recent years [110][111][112][113][114][115][116][117][128][129][130][131][132][133][134][135][136][137][138]…”

Section: Non-oxide Chalcogenidesmentioning

confidence: 99%

Production of electricity and hydrogen by photocatalytic degradation of organic wastes in a photoelectrochemical cell

Lianos

2011

Journal of Hazardous Materials

348

190

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“…The measurements were performed in a polysulfide solution (1 M NaOH, 1 M Na 2 S and 50 mM S) of the type used to stabilize CdX photoanodes (X ) S, Se; see refs [37][38][39][40][41]. All materials showed negative photopotentials at open circuit and anodic photocurrents, as typical of n-type semiconductors.…”

Section: Systematic Investigation Of the Ternary Sulfide Obtained Witmentioning

confidence: 99%

Ternary CdS_xSe₁_-_x Deposited on Ag(111) by ECALE: Synthesis and Characterization

Milani

Loglio

et al. 2005

Langmuir

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Morphology and electronic properties of CdS, CdSe, and the ternary compounds of formula CdSxSe1-x deposited on Ag(111) by ECALE have been characterized as a function of the composition. The number of the attainable x values is limited by the necessity of using well-defined CdS/CdSe deposition sequences. However, the quantitative analysis carried out by XPS and electrochemical stripping experiments indicates that the ECALE method has a good control on composition. The AFM images together with the electrochemical characterization indicate both two-dimensional and three-dimensional growth contributions.The photospectra recorded at CdS film electrodes in liquid junction with an alkaline (poly)sulfide electrolyte show good efficiency of photoconversion and band gap typical of the single crystal. Lower photoconversion efficiency and the presence of subband gap response are observed for CdSe; a possible reason is some crystalline disorder due to lower control of the layer-by-layer deposition in the case of Se. The dependence of band gap on composition of ternary CdSxSe1-x ECALE films is monotonic and in agreement with literature data reported for bulk materials. IntroductionThe interest in the electrochemical deposition of group II-VI compounds, in particular cadmium chalcogenides, stems from its ability to produce good quality materials with a relatively simple, soft procedure, operating at low temperature. Literature reports include preparation of layers of different thickness on various substrates, for potential applications going from solar energy conversion 1-3 to optoelectronics. 4,5 Recently, the electrochemical atomic layer epitaxy (ECALE) method has been proposed by Stickney and co-workers 6,7 for the deposition of well ordered group II-VI compounds. In the ECALE procedure, a binary compound is obtained by alternating the layerby-layer underpotential deposition of the metallic and nonmetallic elements. 6,7 The approach, initially developed for polycrystalline as well as for single-crystal gold substrates, was extended by our group to Ag(111) substrate. 8,9 One major advantage of ECALE method consists of the possibility of optimizing separately the different steps of the alternate electrodeposition by adjusting the solution and potential parameters.The deposition of ternary group II-VI compounds offers the possibility of tuning the band gap to meet specific

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Determination of flat-band position of cadmium sulfide crystals, films, and powders by photocurrent and impedance techniques, photoredox reaction mediated by intragap states

Cited by 75 publications

References 1 publication

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

Production of electricity and hydrogen by photocatalytic degradation of organic wastes in a photoelectrochemical cell

Ternary CdS_xSe₁_-_x Deposited on Ag(111) by ECALE: Synthesis and Characterization

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Determination of flat-band position of cadmium sulfide crystals, films, and powders by photocurrent and impedance techniques, photoredox reaction mediated by intragap states

Cited by 75 publications

References 1 publication

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2‐Based Nanomaterials

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2‐Based Nanomaterials

Production of electricity and hydrogen by photocatalytic degradation of organic wastes in a photoelectrochemical cell

Ternary CdSxSe1-x Deposited on Ag(111) by ECALE: Synthesis and Characterization

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(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

Ternary CdS_xSe₁_-_x Deposited on Ag(111) by ECALE: Synthesis and Characterization