Electron transfer dynamics of peptide‐derivatized Ru<sup>II</sup>‐polypyridyl complexes on nanocrystalline metal oxide films

Hanson, Kenneth; Wilger, Dale J.; Jones, Sean T.; Harrison, Daniel P.; Bettis, Stephanie E.; Luo, Hanlin; Papanikolas, John M.; Waters, Marcey L.; Meyer, Thomas J.

doi:10.1002/bip.22152

Cited by 7 publications

(11 citation statements)

References 62 publications

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“…Assuming that k r and k nr for TiO 2 −RuC and TiO 2 −(X)−Zr−RuC are similar to ZrO 2 − RuC, k inj can be calculated by using τ = 1/(k r + k nr + k inj ). 4 The calculated electron injection rate constant increases in the order a Measured using an integrating sphere. b Weighted average lifetime from the biexponential fit (ex: 445 nm).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Electron transfer from a photoexcited chromophore to a semiconducting metal oxide surface is a critical event in dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells. − Considerable efforts have been dedicated to manipulate electron transfer rates at these interfaces by reducing the electronic coupling between the dye and semiconductor which in turn slows the electron transfer rates. − Spatial separation of the dye and semiconductor is arguably the most common method of reducing electronic coupling and is achieved by two primary strategies: (1) atomic layer deposition (ALD) and (2) synthetic modification of the dye.…”

Section: Introductionmentioning

confidence: 99%

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Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

2015

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Forward and back electron transfer at dye−semiconductor interfaces are pivotal events in dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells. Here we introduce self-assembled bilayers as a strategy for manipulating electron transfer dynamics at these interfaces. The bilayer films are achieved by stepwise layering of bridging molecules, linking ions, and dye molecules on the metal oxide surface. The formation of the proposed architecture is supported by ATR-IR and UV−vis spectroscopy. By using time-resolved emission and transient absorption, we establish that the films exhibit an exponential decrease in electron transfer rate with increasing bridge length. The findings indicate that self-assembled bilayers offer a simple, straightforward, and modular method for manipulating electron transfer dynamics at dye−semiconductor interfaces. ■ INTRODUCTIONElectron transfer from a photoexcited chromophore to a semiconducting metal oxide surface is a critical event in dyesensitized solar cells and dye-sensitized photoelectrosynthesis cells. 1−3 Considerable efforts have been dedicated to manipulate electron transfer rates at these interfaces by reducing the electronic coupling between the dye and semiconductor which in turn slows the electron transfer rates. 4−8 Spatial separation of the dye and semiconductor is arguably the most common method of reducing electronic coupling and is achieved by two primary strategies: (1) atomic layer deposition (ALD) and (2) synthetic modification of the dye.ALD of "insulating" layers between the dye and semiconductor effectively increases their separation and is effective in manipulating electron transfer rates. 9−11 However, this method requires dedicated, high vacuum instrumentation that is less than ideal for large scale production of dye-sensitized devices.The second strategy involves covalently modifying the dye molecules with rigid bridging moieties terminated in a surfacebinding group. 12−15 Despite their elegant design, many of these elongated bridge-dyes lie down on the surface, negating the desired effect. Recently, Meyer and co-workers demonstrated thatwith at least some bridge-dyesincreasing bridge lengths can be effective in slowing electron transfer rates. 16 However, the covalent interaction between the dye and bridge influences the electrochemical and photophysical properties of the dye, making it difficult to differentiate the distance dependence from other variables. 8 Additionally, the multistep synthesis required for bridge-dye molecules limits the generalizability of these systems.In this report, we introduce an alternative strategy, selfassembled bilayers, as a means of controlling the distance between dye and the metal oxide surface. This approach, based on the work of Mallouk and Haga, 17,18 provides a simple and modular method for the self-assembly of bilayer structures on metal oxide surfaces via metal ion linkages. This stepwise assembly method has been successfully implemented with chromophore−catalyst and chromophore−chromophore assemblie...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

2015

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“…Photoinduced oxidation of RuBPY derivatives doped onto SnO 2 and TiO 2 dispersions and films has been well established and could explain the quenched lifetime of RuDCBPY in UiO-67/FTO. − Therefore, to ascertain the role of the FTO substrate as a potential quencher of the RuDCBPY 3 MLCT, films were also grown on conventional SiO 2 -based glass slides since SiO 2 is known to be insulating and, consequently, does not participate in electron transfer with adsorbed RuBPY. − It should be noted that RuDCBPY-UiO67/glass films loaded below 10 m m were difficult to obtain (even under synthetic conditions in which RuDCBPY mole ratios were <1% relative to BPDC). However, at RuDCBPY doping concentrations of 14 m m and above, the observed emission maxima of films on glass were found to be independent of doping concentration ranging between 630 and 640 nm (Figure S4 in Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Solvothermal Growth and Photophysical Characterization of a Ruthenium(II) Tris(2,2′-Bipyridine)-Doped Zirconium UiO-67 Metal Organic Framework Thin Film

et al. 2014

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A thin film of a Ru II (bpy) 2 (dcbpy)Cl 2 , RuDCBPY, doped metal−organic framework of Zr 6 O 4 (OH) 4 (bpdc) 6 , RuDCBPY-UiO67 (where bpy is 2,2′-bipyridine, dcbpy is 5,5′-dicarboxyphenyl-2,2′-bipyridine, and bpdc is 4,4′-biphenyldicarboxylic acid), has been prepared on fluorine-doped tin oxide and glass slides solvothermally. The film is shown to be isostructural with UiO-67 and similarly doped RuDCBPY-UiO67 powders. The photophysical properties of the film show significant line broadening of the diffuse reflectance spectra, a successive red shift of the emission maxima, and biphasic kinetics with increased RuDCBPY doping of UiO-67 films above 10 mm. The two lifetime components are consistent with a dual population of RuDCBPY within the UiO-67 material: a population of RuDCBPY incorporated into the framework of UiO-67 replacing a bpdc ligand and a second population of RuDCBPY encapsulated within the octahedral cavities. The RuDCBPY dopant within the UiO-67 films interact with each other and undergo self-quenching via a resonance energy transfer mechanism. It was determined that the average distance between RuDCBPY is decreased in the film relative to similarly doped powders. This is attributed to an electrostatic effect upon formation of the framework due to increased charge at the bpdc self-assembled monolayer at the surface of the substrate. ■ INTRODUCTIONMetal−organic framework (MOF) materials continue to gain increasing attention due to their large surface areas and applicability toward catalysis, sensing, separations, and photonics. MOF engineering has, in recent years, been extended by the development of thin films, allowing for more specific/specialized applications. 1−30 The current state of the art of MOF thin film fabrication and development has recently been reviewed extensively. 31−33 Films consisting of MOFs have been prepared and grown on a variety of substrates by a number of different methods. Of the preparative methods employed to date, the most straightforward involves incubating the substrate along with the reaction mixture during the solvothermal process. 32,34−37 Solvothermal synthesis of MOF thin films has been shown to be facilitated by prior formation of a self-assembled, oriented, organic layer terminally functionalized to mimic the connectivity of one of the native MOF ligands. 32,38−40 Thin films composed of robust, stable, and porous MOFs are of particular interest in light of the harsh conditions necessary to carry out a variety of reactions and processes. The UiO (University of Oslo) series of zirconium-based materials are promising candidates owing to their exceptional stability under a variety of thermal, mechanical, and solvent conditions. 41−43 The Zr 6 O 4 (OH) 4 (COO) 6 clusters of the UiO-66, -67, and -68 frameworks arrange in such a way that two types of cavities are formed: a tetrahedral and larger octahedral cavity. 44,45 For UiO-67, in which the connecting ligand is a biphenyldicarboxylate, the diameters of the tetrahedral and octahedral pores are 11.5 and 23 Å, respe...

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“…Since there is a parallel between our recent work in understanding the role of semiconducting oxide nanoparticles in enhancing the Raman activities of molecules adsorbed on them − and the characteristics of peptide–metal oxide nanointerfaces, − we thought it would be interesting to investigate them. In our work on surface enhanced Raman scattering (SERS) on semiconducting nanoparticles, we have shown that the enhancement of Raman activities arises from a large increase in polarizability due to charge transfer from the molecule to the semiconducting nanoparticle. , Furthermore, we have delineated the specific role of factors like metal oxide composition, nanoparticle size, solvent, and pH on the observed Raman activities .…”

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confidence: 99%

“…Given the recent interest in biophotovoltaic devices and the necessity of understanding the role played by small polypeptide chains adsorbed on semiconducting nanoparticles in directing and controlling rates of electron transfer, , we directed our attention to investigating the nature of charge transfer at peptide–metal oxide nanointerfaces. − Our focus is to examine the role of both peptide secondary structure and the presence of cationic amino acids in the peptide in influencing both the binding energetics and the interfacial electronic characteristics. In order to address these twin issues, we carried out calculations on the A6K and A7 (Ac-AAAAAAA-NH 2 ) peptides.…”

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confidence: 99%

Probing the Nature of Charge Transfer at Nano–Bio Interfaces: Peptides on Metal Oxide Nanoparticles

Tarakeshwar

Palma

Holland

et al. 2014

J. Phys. Chem. Lett.

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Characterizing the nano-bio interface has been a long-standing endeavor in the quest for novel biosensors, biophotovoltaics, and biocompatible electronic devices. In this context, the present computational work on the interaction of two peptides, A6K (Ac-AAAAAAK-NH2) and A7 (Ac-AAAAAAA-NH2) with semiconducting TiO2 nanoparticles is an effort to understand the peptide-metal oxide nanointerface. These investigations were spurred by recent experimental observations that nanostructured semiconducting metal oxides templated with A6K peptides not only stabilize large proteins like photosystem-I (PS-I) but also exhibit enhanced charge-transfer characteristics. Our results indicate that α-helical structures of A6K are not only energetically more stabilized on TiO2 nanoparticles, but the resulting hybrids also exhibit enhanced electron transfer characteristics. This enhancement can be attributed to substantial changes in the electronic characteristics at the peptide-TiO2 interface. Apart from understanding the mechanism of electron transfer (ET) in peptide-stabilized PS-I on metal oxide nanoparticles, the current work also has implications in the development of novel solar cells and photocatalysts.

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Electron transfer dynamics of peptide‐derivatized Ru^II‐polypyridyl complexes on nanocrystalline metal oxide films

Cited by 7 publications

References 62 publications

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Solvothermal Growth and Photophysical Characterization of a Ruthenium(II) Tris(2,2′-Bipyridine)-Doped Zirconium UiO-67 Metal Organic Framework Thin Film

Probing the Nature of Charge Transfer at Nano–Bio Interfaces: Peptides on Metal Oxide Nanoparticles

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Electron transfer dynamics of peptide‐derivatized RuII‐polypyridyl complexes on nanocrystalline metal oxide films

Cited by 7 publications

References 62 publications

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Modulating Electron Transfer Dynamics at Dye–Semiconductor Interfaces via Self-Assembled Bilayers

Solvothermal Growth and Photophysical Characterization of a Ruthenium(II) Tris(2,2′-Bipyridine)-Doped Zirconium UiO-67 Metal Organic Framework Thin Film

Probing the Nature of Charge Transfer at Nano–Bio Interfaces: Peptides on Metal Oxide Nanoparticles

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Electron transfer dynamics of peptide‐derivatized Ru^II‐polypyridyl complexes on nanocrystalline metal oxide films