Reversible switching in self-assembled monolayers of azobenzene thiolates on Au (111) probed by threshold photoemission

Heinemann, N.; Grunau, Jan; Leißner, Till; Andreyev, O.; Kühn, Sonja; Jung, Ulrich; Zargarani, Dordaneh; Herges, Rainer; Magnussen, Olaf M.; Bauer, Michael

doi:10.1016/j.chemphys.2012.03.025

Cited by 17 publications

(20 citation statements)

References 45 publications

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“…44,47,49,[236][237][238][239][240] Terminal functional groups displayed at interfaces define both physical and chemical surface properties, making it possible to tailor surfaces down to the nanoscale through chemical patterning. 14,15,[241][242][243][244][245][246][247] In this section, we briefly discuss molecular patterning of SAMs through soft lithography, scanning probe lithography, and related techniques (Fig. 5).…”

Section: Molecular Patterning and Its Applicationsmentioning

confidence: 99%

From the bottom up: dimensional control and characterization in molecular monolayers

et al. 2013

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Self-assembled monolayers are a unique class of nanostructured materials, with properties determined by their molecular lattice structures, as well as the interfaces with their substrates and environments. As with other nanostructured materials, defects and dimensionality play important roles in the physical, chemical, and biological properties of the monolayers. In this review, we discuss monolayer structures ranging from surfaces (two-dimensional) down to single molecules (zero-dimensional), with a focus on applications of each type of structure, and on techniques that enable characterization of monolayer physical properties down to the single-molecule scale.

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Section: Molecular Patterning and Its Applicationsmentioning

confidence: 99%

From the bottom up: dimensional control and characterization in molecular monolayers

et al. 2013

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“…Self-assembled monolayers (SAMs) are frequently proposed as robust molecular coatings to tune surface properties. − The incorporation of molecular switches into SAMs allows for changing their properties by light. − Azo-biphenyl derivatives , or alkanethiols ω-functionalized with azobenzene − are commonly used to achieve this goal. Both classes of compounds form densely packed SAMs on gold. , For azo-biphenyl SAMs, the photoisomerization has been demonstrated by Pace et al , In azobenzenealkanethiolate SAMs, the chromophore density has to be reduced to enable photoisomerization. ,,− …”

Section: Introductionmentioning

confidence: 99%

Differing Isomerization Kinetics of Azobenzene-Functionalized Self-Assembled Monolayers in Ambient Air and in Vacuum

et al. 2016

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Azobenzene-alkanethiols in self-assembled monolayers (SAMs) on Au(111) exhibit reversible trans-cis photoisomerization when diluted with alkanethiol spacers. Using these mixed SAMs, we show switching of the linear optical and second harmonic response. The effective switching of these surface optical properties relies on a reasonably large cross section and a high photoisomerization yield as well as a long lifetime of the metastable cis isomer. We quantiﬁed the switching process by X-ray absorption spectroscopy. The cross sections for the trans-cis and cis-trans photoisomerization with 365 and 455 nm light, respectively, are one order of magnitude smaller than in solution. In vacuum the 365 nm photostationary state comprises 50-74% of the molecules in the cis form, limited by their rapid thermal isomerization back to the trans state. In contrast, the 455 nm photostationary state contains nearly 100% trans-azobenzene. We determined time constants for the thermal cis-trans isomerization of only a few minutes in vacuum and in a dry nitrogen atmosphere, but of more than one day in ambient air. Our results suggest that adventitious water adsorbed on the SAM's surface stabilizes the polar cis conﬁguration of azobenzene under ambient conditions. The back reaction rates differing by two orders of magnitude underline the huge inﬂuence of the environment and accordingly its importance when comparing various experiments.

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“…Likewise the case for alkanethiolates on Au surface, the Au surface state is quenched by the adsorbed layer through the Au-S bonding. 13,14 The molecular resonance states were not found in the examined spectrum range. In previous photoemission spectroscopy (PES) studies on alkanethiolate SAMs, electronic states were not observed obviously in the energy range AE3 V with respect to the Fermi level.…”

Section: Resultsmentioning

confidence: 89%

Tailoring electronic states of a single molecule using adamantane-based molecular tripods

Katano

Kim

Kitagawa

et al. 2013

Phys. Chem. Chem. Phys.

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Adsorption structures and electronic states of molecular tripods, having a Br atom (BATT) and a ferrocene derivative (Ferrocene-ATT) at the head part of the adamantane-based trithiolate, adsorbed on Au(111) have been investigated using low temperature scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). We found that BATT and Ferrocene-ATT form self-assembled monolayers (SAMs), and their orderings are identical to one another, which suggests that the adsorption structure of adamantane-based molecular tripods is independent of the type of functional substituent attached to the head part. The electronic states originated from the ferrocene group were confirmed in the STS spectrum of Ferrocene-ATT whereas those are absent in the BATT spectrum. We note that the ferrocene part has few interactions with the Au substrate owing not only to the upright geometry of Ferrocene-ATT but also to the insulative properties of the adamantane base. The STS mapping revealed the spatial distribution of the electronic state of Ferrocene-ATT.

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Reversible switching in self-assembled monolayers of azobenzene thiolates on Au (111) probed by threshold photoemission

Cited by 17 publications

References 45 publications

From the bottom up: dimensional control and characterization in molecular monolayers

From the bottom up: dimensional control and characterization in molecular monolayers

Differing Isomerization Kinetics of Azobenzene-Functionalized Self-Assembled Monolayers in Ambient Air and in Vacuum

Tailoring electronic states of a single molecule using adamantane-based molecular tripods

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