Self-Assembly of 1,4-Benzenedimethanethiol Self-Assembled Monolayers on Gold

Hamoudi, Hicham; Prato, Mirko; Dablemont, Céline; Cavalleri, Ornella; Canepa, M.; Esaulov, Vladimir A.

doi:10.1021/la904317b

Cited by 83 publications

(156 citation statements)

References 63 publications

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“…However, the main component centered at 163.2 ± 0.2 eV, constituting 98 ± 2 %, can be assigned to unbound thiol moieties (-SH). 42 This confirms that the chemical interaction between MPTS and rGO is directed by the Si-O-C path, leaving the SH group exposed to bind to the QDs. 2) eV, a typical position for silanes.…”

Section: Resultssupporting

confidence: 53%

Efficient charge transfer in solution-processed PbS quantum dot–reduced graphene oxide hybrid materials

et al. 2015

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† Electronic Supplementary Information (ESI) available: XPS analysis of GO and rGO; Functionalization of the (r)GO; XPS analysis of ATP and ABA functionalized (r)GO and TEM images of the QD coupling results; Estimation of the density of PbS QDs on the (r)GO sheets; Complementary control experiments: Fluorescence spectroscopy characterization of MUA-capped PbS QDs and effect of EtOH washing; Raman characterization; and PL dynamics in core-shell PbS/CdS QDs and silane-f-(r)GO hybrid materials. SeeQuantum dot -graphene hybrid materials have raised significant interest due to the unique synergy of the optical properties of colloidal quantum dots (QDs) and the transport properties of graphene. This stimulated the development of low-cost and up-scalable solution-processed strategies for hybrid materials with potential application in light harvesting and opto-electronic devices. Here we report a versatile covalent-linking based approach for the functionalization of reduced graphene oxide (rGO), to prepare a variety of QD-rGO hybrid dispersions with QDs of different size and composition (PbS, PbS/CdS and CdSe QDs), and shape (CdSe/CdS dot-in-rods). We achieved a well-controlled QD coverage of the rGO sheets by functionalizing the rGO surface with mercapto-silane linkers. A further spectroscopic investigation of near-infrared PbS QD-rGO materials demonstrates efficient electronic coupling between both materials. The QD photoluminescence emission quenching and exciton lifetime shortening up to 95%, together with subtle graphene Raman G-band shifts upon QD linking, supports electron transfer as the dominant relaxation pathway from the QD to the rGO. The use of core/shell PbS/CdS QDs allows tuning of the transfer efficiency from 94% for a 0.2 nm thin CdS shell, down to 30% for a 1.1 nm thick shell.

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Section: Resultssupporting

confidence: 53%

Efficient charge transfer in solution-processed PbS quantum dot–reduced graphene oxide hybrid materials

et al. 2015

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“…3,) show quite steep Au-related slopes. Structures of this kind were already observed, with less evidence, in the case of some molecular systems on compact gold surfaces [46], where they could be related to a small shift of the intense reflectivity onset of flat gold. On the granular surface of this work, the effect could have been also magnified by conceivable surface plasmon resonance shifts [47].…”

Section: In Situ Difference Spectramentioning

confidence: 95%

Yeast Cytochrome c Monolayer on Flat and Nanostructured Gold Films Studied by UV–Vis Spectroscopic Ellipsometry

et al. 2011

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Spectroscopic ellipsometry (SE) has been used to investigate the adsorption of yeast cytochrome c (YCC) on gold films. YCC is a prototypical molecular system to evaluate the sensitivity and reliability of optical methods in probing conformational changes upon adsorption at surfaces. Measurements have been performed in situ in aqueous solutions at room temperature. We have applied to monolayer-thick YCC films the same scheme of analysis of SE spectra used in our recent works on thiolate self-assembled monolayers on gold, exploiting the so-called δ and δ difference spectra. A comparison between δ and δ spectra obtained from YCC adsorption on flat and cluster-assembled nanostructured gold films, obtained by supersonic cluster beam deposition is proposed. For both kinds of substrate δ and δ , difference spectra show well-defined features related to molecular optical absorptions typical of the so-called heme group, in particular the Soret band at about 410 nm. These features appear in the same position found for molecules in solution, suggesting that YCC native conformation is maintained upon adsorption also in the case of a substrate with typical roughness at the nanoscale.

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“…We recall that the S Au component appears with a lower intensity, because of attenuation of intensity of electrons passing through the organic layer. 23,24 Because the BPD molecules are longer they result in a greater attenuation of electrons passing through the thicker layer and the S Au intensity is lower than for BDMT. We shall return to this point later.…”

Section: Xps Measurementsmentioning

confidence: 99%

“…The dJ BPD curve shows a dip for wavelengths less than 350 nm (minimum around 275 nm), a behavior similar to the BDMT case, for which it was previously 23 assigned to absorption, related to aromatic rings, eventually inuenced by intermolecular interactions in the SAM. 23 We performed a measurement of absorption on a sample of BPD solution in water (in which BPD is more easily soluble than in hexane), which indeed shows absorption below 325 nm wavelength range (rst peak at 293 nm; see inset in Fig. 5).…”

Section: Spectroscopic Ellipsometrymentioning

confidence: 99%

“…[52][53][54] Here we ask ourselves the question whether it is indeed possible to build a multilayer SAM starting from the highly quality dithiol SAM? We base ourselves on the results of these earlier works, 23,24,50 and have used a combination of SE, and XPS to study the formation of the bilayer of BDMT and also 5,5 0 -bis(mercaptomethyl)-2,2 0 -bipyridine (BPD) self-assembled lms on Au, with intercalated Ag atoms. In the following we refer to these generically as DT (dithiols).…”

Section: Introductionmentioning

confidence: 99%

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Going beyond the self-assembled monolayer: metal intercalated dithiol multilayers and their conductance

et al. 2014

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A study of the self-assembly of silver atom intercalated 5,5 0 -bis(mercaptomethyl)-2,2 0 -bipyridine (BPD; HS-CH 2 -(C 5 H 3 N) 2 -CH 2 -SH) and 1,4-benzenedimethanethiol (BDMT; HS-CH 2 -(C 6 H 4 )-CH 2 -SH)) dithiol (DT) multilayers on gold is presented. The bilayer of these SAMs can be obtained starting from the exposure of a DT monolayer to a concentrated silver ion solution. After grafting the silver atoms on the sulfur end group, the incubation of the resulting DT-Ag SAM in a DT solution leads to the formation of a DT-Ag-DT bilayer. This process was extended to make a multilayer structure. The corresponding changes in these self-assembled layers on Au are characterized by X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE) measurements, and I-V characteristics. Our interpretation of evolution in the absorbed layer are based on changes in intensities of peaks in XPS related to S bound to substrate or Ag and in -SH groups, as well as changes in thickness and absorption features in SE measurements. The latter show the evolution in absorbance wavelength as a function of thickness and indicate a decrease in the HOMO-LUMO gap from about 4.5 eV to 4 eV. The I-V characteristics show a significant bias dependence on the number of the BPD layers and there appears to be a transition from tunneling to a hopping regime when going from the single to the multiple layers.

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Self-Assembly of 1,4-Benzenedimethanethiol Self-Assembled Monolayers on Gold

Cited by 83 publications

References 63 publications

Efficient charge transfer in solution-processed PbS quantum dot–reduced graphene oxide hybrid materials

Efficient charge transfer in solution-processed PbS quantum dot–reduced graphene oxide hybrid materials

Yeast Cytochrome c Monolayer on Flat and Nanostructured Gold Films Studied by UV–Vis Spectroscopic Ellipsometry

Going beyond the self-assembled monolayer: metal intercalated dithiol multilayers and their conductance

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