Effects of Fe cations in ruthenium-complex multilayers fabricated by a layer-by-layer method

Oyama, Makiko; Ozawa, Hiroaki; Nagashima, Takumi; Haga, Masa‐aki; Ishida, Takao

doi:10.1039/c5cp07970e

Cited by 6 publications

(5 citation statements)

References 39 publications

(78 reference statements)

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“…The kinetics were comparable at 456 and 380 nm, and decayed with a rate constant of 3.0 × 10 8 s –1 . Similar excited state quenching of ruthenium coordination complexes by Cu II , , Mn II , , and Fe II ions − was observed previously and attributed to either energy (eq ) or electron transfer (eq ). …”

Section: Resultsmentioning

confidence: 90%

Elucidating the Role of the Metal Linking Ion on the Excited State Dynamics of Self-Assembled Bilayers

et al. 2018

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Metal ion-linked, self-assembled multilayers on nanocrystalline metal oxide surfaces have recently emerged as an effective strategy for manipulating energy and electron transfer dynamics at organic−inorganic interfaces. The choice of metal ion can have a large impact on the stability, loading concentration, and other properties of the films. Here we report our investigation into the role of the linking ion on the subnanosecond excited state dynamics in the bilayer films (TiO 2 −B−M−RuP). While metal linkers like Cd II , La III , Sn IV , Zn II , and Zr IV are photochemically inert, paramagnetic linking ions such as Cu II , Fe II , and Mn II quench the excited state of the dye with a rate constant on the order of 10 8 s −1 . The absence of new spectral features in the transient absorption spectrum suggests that energy transfer, and not electron transfer, is responsible for the excited state quenching. On TiO 2 , the electron injection rate for TiO 2 −B−M−RuP is an order of magnitude slower (∼1 × 10 9 s −1 ) than for the dye directly on TiO 2 (∼3 × 10 10 s −1 ) due to increased spatial separation and reduced electronic coupling between the dye and the surface. In dye-sensitized solar cells, the TiO 2 −B−M−RuP devices exhibit a notably lower J sc but higher V oc compared to TiO 2 −RuP with even lower photocurrents for Cu II , Fe II , and Mn II bilayers presumably at least in part due to competitive quenching of the excited state by the metal ion. The increases in V oc are offset by the decrease in J sc ; thus, the overall efficiency of the bilayer devices is lower than the that of the parent, monolayer device.

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Section: Resultsmentioning

confidence: 90%

Elucidating the Role of the Metal Linking Ion on the Excited State Dynamics of Self-Assembled Bilayers

et al. 2018

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“… Although the metal ion loading process can be fast (<15 min), , MO 2 -B films were submerged in metal ion solution overnight to ensure complete coordination. For these films, the metal ion coordination is not surprising given that these ions were specifically selected because the metal ions and the starting salts are known to readily coordinate to CO 2 H and/or PO 3 H 2 groups as described in the metal–organic framework literature. − …”

Section: Resultsmentioning

confidence: 99%

Self-Assembled Bilayers on Nanocrystalline Metal Oxides: Exploring the Non-Innocent Nature of the Linking Ions

et al. 2017

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Self-assembled bilayers on nanocrystalline metal oxide films are an increasingly popular strategy for modulating electron and energy transfer at dye-semiconductor interfaces. A majority of the work to date has relied on Zr and Zn linking ions to assemble the films. In this report, we demonstrate that several different cations (Cd, Cu, Fe, La, Mn, and Sn) are not only effective in generating the bilayer assemblies but also have a profound influence on the stability and photophysical properties of the films. Bilayer films with Zr ions exhibited the highest photostability on both TiO and ZrO. Despite the metal ions having a minimal influence on the absorption/emission energies and oxidation potentials of the dye, bilayers composed of Cu, Fe, and Mn exhibit significant excited-state quenching. The excited-state quenching decreases the electron injection yield but also, for Cu and Mn bilayers, significantly slows the back electron transfer kinetics.

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“…39 Incorporation of redox active linking ions like Fe 2+ increased the electron transport capabilities of the film via both hopping and tunneling mechanisms. 40 XPS, ellipsometry, and TOF-SIMS measurements indicated that multilayer growth was initially limited to 6−7 layers, which the authors attribute to the large tilt angle creating a domain boundary as depicted in Figure 6. 41 However, through variation in the film loading conditions, Haga and co-workers increased the monolayer loading and film uniformity, enabling the formation of at least 65 monolayers.…”

Section: Redox Active Ruthenium Polypyridyl Multilayersmentioning

confidence: 99%

“…Cyclic voltammograms of the films exhibited nonequivalent anodic and cathodic currents depending on the energetic/redox ordering of the species, indicating that multilayers can potentially serve as a rectifying interface . Incorporation of redox active linking ions like Fe 2+ increased the electron transport capabilities of the film via both hopping and tunneling mechanisms …”

Section: Metal Ion-linked Assemblies On Planar Surfacesmentioning

confidence: 99%

Metal Ion-Linked Molecular Multilayers on Inorganic Substrates: Structure and Applications

Arcidiacono

Hanks

Hanson

2023

ACS Appl. Opt. Mater.

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Metal ion-linked multilayers have emerged as a simple and modular means of assembling molecular components on an inorganic substrate. The choice of molecules, based on their excited state energies and redox potentials, has enabled the directional control of energy and electron transfer events for application in electrochromics, solar energy harvesting, molecular rectifiers, photocatalysis, and more. Here, we recount the more than 35-year journey of metal ion-linked multilayers and their transition from planar to mesoporous substrates and from homogeneous to heterogeneous multilayers. This includes showcasing the vast range of components (i.e., substrates, metal ions, and molecules), structural insights, and applications. We also highlight current limitations in our knowledge of and ability to control these systems which must be overcome to realize the full potential of metal ion-linked multilayers.

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Effects of Fe cations in ruthenium-complex multilayers fabricated by a layer-by-layer method

Cited by 6 publications

References 39 publications

Elucidating the Role of the Metal Linking Ion on the Excited State Dynamics of Self-Assembled Bilayers

Elucidating the Role of the Metal Linking Ion on the Excited State Dynamics of Self-Assembled Bilayers

Self-Assembled Bilayers on Nanocrystalline Metal Oxides: Exploring the Non-Innocent Nature of the Linking Ions

Metal Ion-Linked Molecular Multilayers on Inorganic Substrates: Structure and Applications

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