Photoluminescence of Adsorbed Dyes<sup>1</sup>

Lendvay, E.

doi:10.1021/j100887a005

Cited by 12 publications

(5 citation statements)

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“…Hence, at 5 μM, the observed photoelectrochemical responses qualitatively indicated the innate spectral profile for sensitization by each dye. Notably, for each plot in Figure , the wavelength corresponding to the maximum sub-bandgap external quantum yield was uniformly offset from the wavelength of maximum absorbance of the dissolved dye (Table ), consistent with the notion that sensitization occurred specifically through adsorbed dye at the photoelectrode surface. ,− Sensitized photocurrents at sub-bandgap wavelengths were not observed for all investigated dyes. Specifically, sensitization was not detected in electrolytes containing dissolved metal phthalocyanine tetrasulfonic acid dyes (SI, Figure S4) with standard potentials for oxidation that were more negative than E vb,GaP…”

Section: Resultssupporting

confidence: 71%

“…In all cases, the wavelength for maximum absorptance was red-shifted from the wavelength of maximum sensitization. Irrespective of whether the dye was purposely tethered to the electrode surface or partitioned from solution onto the electrode surface (i.e., physisorbed), a red-shift in the sensitized spectrum is a hallmark of sensitized injection from photoexcited chromophores specifically at a semiconductor electrode interface ,− and suggests that a sensitization process occurred at the semiconductor electrode/electrolyte interface. Second, sensitized cathodic currents were only measured in experiments featuring dyes with excited states that had enough oxidizing strength to abstract an electron from (i.e., inject a hole into) p-GaP(100).…”

Section: Discussionmentioning

confidence: 99%

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Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Chitambar¹,

Wang²,

Liu

et al. 2012

J. Am. Chem. Soc.

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The steady-state photoelectrochemical responses of p-GaP photoelectrodes immersed in aqueous electrolytes and sensitized separately by six triphenylmethane dyes (rose bengal, rhodamine B, crystal violet, ethyl violet, fast green fcf, and brilliant green) have been analyzed. Impedance measurements indicated that these p-GaP(100) photoelectrodes operated under depletion conditions with an electric field of ∼8.5 × 10(5) V cm(-1) at the p-GaP/solution interface. The set of collected wavelength-dependent quantum yield responses were consistent with sensitization occurring specifically from adsorbed triphenylmethane dyes. At high concentrations of dissolved dye, the measured steady-state photocurrent-potential responses collected at sub-bandgap wavelengths suggested unexpectedly high (>0.1) net internal quantum yields for sensitized hole injection. Separate measurements performed with rose bengal adsorbed on p-GaP surfaces pretreated with (NH(4))(2)S verified efficient sensitized hole injection. A modified version of wxAMPS, a finite-difference software package, was utilized to assess key operational features of the sensitized p-GaP photocathodes. The net analysis showed that the high internal quantum yield values inferred from the experimental data were most likely afforded by the internal electric field present within p-GaP, effectively sweeping injected holes away from the interface and minimizing their participation in deleterious pathways that could limit the net collection yield. These simulations defined effective threshold values for the charge carrier mobilities (≥10(-6) cm(2) V(-1) s(-1) and ≥10(-1) cm(2) V(-1) s(-1) at dopant densities of 10(18) and 10(13) cm(-3), respectively), hole injection rate constants (≥10(12) s(-1)), and surface trap densities (10(12) cm(-2)) needed to attain efficient hole collection with the quality of p-GaP materials used here. The cumulative experimental and modeling data thus provide insight on design strategies for assembling new types of dye-sensitized photocathodes that operate under depletion conditions.

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Section: Resultssupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Chitambar¹,

Wang²,

Liu

et al. 2012

J. Am. Chem. Soc.

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“…adsorbed xanthene dyes have been investigated on surfaces of various solid materials such as porous (2b, 2d, 7) and nonporous (8-11) silica type glasses, semiconductors (10,(12)(13)(14), various surface-hydroxylated materials (14), crystals of polycyclic aromatic hydrocarbons ( 15), silver islands ( 16), and gold films (8).…”

Section: Introductionmentioning

confidence: 99%

Adsorption characteristics of rhodamine 6G on montmorillonite and laponite, elucidated from electronic absorption and emission spectra

Grauer¹,

Avnir²,

Yariv³

1984

Can. J. Chem.

100

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The adsorption of the cationic dye rhodamine 6G by montmorillonite (Wyoming bentonite) and laponite (synthetic hectorite) was studied by visible and fluorescent spectroscopy and by X-ray diffraction methods. Adsorption of the dye takes place by the mechanism of cation exchange. X-ray data indicate that the adsorbed cationic dye is located in the interlayer spaces of both minerals. It was found that adsorption prevents the dimerization of the dye, and gives rise to red shifts of the principal absorption band of the dye. A study of the effect of varying concentration of dye or clay on the location and intensity of this band proved to be useful in determining the adsorption capacity of the clay. The observed spectral changes are linked to surface polarity and to clay flocculation. At concentrated suspensions of montmorillonite, an additional weak absorption shoulder is obtained at 470-490 nm, which may be attributed to aggregated dye molecules, probably trapped within the cavities of book-house structured flocs. Due to steric hindrance rhodamine 6G does not give IT interactions with the oxygen plane of the silicate layer. Therefore the adsorption of the dye by expanding clay minerals does not give rise to metachromasy. Fluorescence of the adsorbed dye is reported: it is red shifted and quenched relative to aqueous solutions. The use of fluorescence spectra to determine the saturation point is described, and aging and ultrasonic effects on spectral features are presented and discussed.ZVl GRAUER, DAVID AVNIR et SHMUEL YARIV. Can. J. Chem. 62, 1889 (1 984).Faisant appel a la diffraction des rayons-X et a la spectroscopie visible et de fluorescence, on a CtudiC l'adsorption du colorant cationique rhodamine 6G par la montmorillonite (bentonite du Wyoming) et par la laponite (hectorite synthCtique). L'adsorption du colorant se fait par un mCcanisme impliquant un Cchange de cations. Les donnCes de rayons-X indiquent que, dans le cas de chacun des deux minkraux, le colorant cationique est adsorb6 dans les espaces interstitiels. On a trouvt que l'adsorption empeche la dimCrisation du colorant. A la suite de l'adsorption, la principale bande d'adsorption du colorant se dCplace vers le rouge. Une ttude de l'effet d'un changement de concentration du colorant ou de l'argile sur la position et I'intensitC de cette bande s'avkre un outil utile pour dkterminer la capacitC d'adsorption de l'argile. Les changements spectraux obsewCs sont lies a la polarit6 de la surface et a la floculation de l'argile. Pour des suspensions concentries de montmorillonite, on observe une adsorption supplCmentaire faible qui apparait comme un Cpaulement a 470-490 nm et que I'on peut attribuer une aggregation de molCcuies de colorant qui sont probablement emprisonnCes dans les cavitCs des flocons. i a rhodamine 6G, a cause de I'encombrement stkrique, n'a pas d'interactions IT avec le plan d'oxygenes de la couche de silicate. Par conskquent, l'adsorption du colorant par la dilatation des minkraux argileux ne provoque pas de mCtachromasie. On rapporte la...

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“…This result shows that electron injection into the conduction band of Sn02, in fact, takes place via excited H2TPP. (2) It has been shown10,11 that the rate of intersystem crossing from St to Tx is enhanced in some molecules adsorbed on solids containing heavy atoms (external heavy atom effect). This effect should result in quenching of fluorescence and the enhancement of phosphorescence.…”

Section: Discussionmentioning

confidence: 99%

Fluorescence quenching via charge injection at the interface between tetraphenylporphine and tin(IV) oxide

Tanimura¹,

Kawai²,

Sakata³

1979

J. Phys. Chem.

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Photoluminescence of Adsorbed Dyes¹

Cited by 12 publications

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Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Adsorption characteristics of rhodamine 6G on montmorillonite and laponite, elucidated from electronic absorption and emission spectra

Fluorescence quenching via charge injection at the interface between tetraphenylporphine and tin(IV) oxide

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Photoluminescence of Adsorbed Dyes1

Cited by 12 publications

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Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Dye-Sensitized Photocathodes: Efficient Light-Stimulated Hole Injection into p-GaP Under Depletion Conditions

Adsorption characteristics of rhodamine 6G on montmorillonite and laponite, elucidated from electronic absorption and emission spectra

Fluorescence quenching via charge injection at the interface between tetraphenylporphine and tin(IV) oxide

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Photoluminescence of Adsorbed Dyes¹