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Bossard-Giannesini L, Cardenas L, Cruguel H, Demessence A, Loffreda D, Pluchery O. How far the chemistry of self-assembled monolayers on gold surfaces affects their work function? NANOSCALE 2023; 15:17113-17123. [PMID: 37850381 DOI: 10.1039/d3nr03172a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Self-assembled monolayers composed of various long-chain aliphatic molecules and different tail functional groups have been synthesized on the Au(111) surface and characterized by Kelvin probe force microscopy and ultraviolet photoelectron spectroscopy. Carboxy, amino, thio and methyl terminal groups have been considered in the design of self-assembled monolayers with different aliphatic chain lengths (from C6 to C16). Work function measurements by Kelvin probe force microscopy have been carried out under a controlled and room atmosphere. Remarkably, a reduction of the relative humidity from 40% to 3% has induced a work function shift of up to 0.3 eV. As expected, the changes of the chain length of the aliphatic moiety and of the tail group have a significant impact on the tuning of the measured work function (3.90 eV for dodecanethiol versus 4.57 eV for mercaptohexadecylamine). Surprisingly, the change of the net dipole moment of the tail group (sign and amplitude) does not dominate the work function variations. In contrast, the change of the chain length and the possibility of the tail group to form a complex hydrogen bond network between molecules lead to significant modulations of the work function. In order to interpret these original findings, density functional theory models of equivalent self-assembled monolayers adsorbed on the Au(111) surface have been developed at an unprecedented level of description with large supercells including simultaneously 27 co-adsorbed molecules and weak van der Waals interactions between them. Such large systems have allowed the theoretical modeling of complex hydrogen bond networks between molecules when possible (carboxy tail group). The comparison between computed and measured work functions shows a striking agreement, thus allowing the disentanglement of the previously mentioned competing effects. This consistency between experiment and theory will help in designing the electronic properties of self-assembled monolayers in the context of molecular electronics and organic transistors.
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Affiliation(s)
- Léo Bossard-Giannesini
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
| | - Luis Cardenas
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON - UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France
| | - Hervé Cruguel
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
| | - Aude Demessence
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON - UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France
| | - David Loffreda
- ENSL, CNRS, Laboratoire de Chimie UMR 5182, 46 Allée d'Italie, 69364 Lyon Cedex, France.
| | - Olivier Pluchery
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
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Pang B, Iqbal D, Sarfraz A, Biedermann PU, Erbe A. Differences in perchlorate adsorption to azobenzene monolayers on gold formed from thioacetate and thiol precursors. Z PHYS CHEM 2022. [DOI: 10.1515/zpch-2021-3143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Modification of metal surfaces with complex molecules opens interesting opportunities to build additional functionality into these surfaces. In this work, self assembled monolayers (SAMs) based on the same photoswitchable azobenzene motif but with different head groups have been synthesized and their SAMs on Au(111)/Si substrates have been characterized. 3-[(4-phenylazo)phenoxy]propyl thiol (PAPT) and its acetyl group protected analog, 3-[(4-phenylazo)phenoxy]propyl thioacetate (PAPA), have been synthesized. SAMs from PAPT and PAPA have been characterized by infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ellipsometry and cyclic voltammetry (CV). The SAM-forming units of both SAMs are the same, as confirmed by IR and XPS, and the SAMs have similar surface coverage, as evidenced by analysis of the reductive desorption peaks in CVs. The tilt angle of the azobenzene moiety was ca. 75° with respect to the surface normal as determined by IR spectroscopy, i.e., the molecules are lying quite flat on the gold surface. Despite similar surface coverages, the CVs for PAPT in aqueous perchlorate solution show a typical perchlorate adsorption peak to gold, whereas the corresponding experiments with PAPA show no perchlorate adsorption at all. In conclusion, SAM formation can lead to an increase in the number of electrochemically accessible surface sites on the final, SAM covered surface. Whether the amount of such sites increases or decreases, depends on the precursor. The precursor most likely affects the adsorption mechanism and thus the atomic surface structure of the metal at the metal/SAM interface. Thus, details of the SAM formation mechanism, which is affected by the precursor used, can have quite strong effects on the electrochemical properties, and likely also electrocatalytic properties, of the resulting modified surface.
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Affiliation(s)
- Beibei Pang
- Max-Planck-Institut für Eisenforschung GmbH , Max-Planck-Str., 1, 40237 Düsseldorf , Germany
| | - Danish Iqbal
- Max-Planck-Institut für Eisenforschung GmbH , Max-Planck-Str., 1, 40237 Düsseldorf , Germany
| | - Adnan Sarfraz
- Max-Planck-Institut für Eisenforschung GmbH , Max-Planck-Str., 1, 40237 Düsseldorf , Germany
| | - P. Ulrich Biedermann
- Max-Planck-Institut für Eisenforschung GmbH , Max-Planck-Str., 1, 40237 Düsseldorf , Germany
| | - Andreas Erbe
- Department of Materials Science and Engineering , NTNU, Norwegian University of Science and Technology , 7491 Trondheim , Norway
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Kunfi A, Ábrahám Á, Gyulai G, Kiss É, London G. Light‐Induced and Thermal Isomerization of Azobenzenes on Immobilized Gold Nanoparticle Aggregates. Chempluschem 2022; 87:e202200153. [DOI: 10.1002/cplu.202200153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/24/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Attila Kunfi
- Research Centre for Natural Sciences: Termeszettudomanyi Kutatokozpont Institute of Organic Chemistry HUNGARY
| | - Ágnes Ábrahám
- Eötvös Loránd Tudományegyetem: Eotvos Lorand Tudomanyegyetem Laboratory of Interfaces and Nanostructures HUNGARY
| | - Gergő Gyulai
- Eötvös Loránd Tudományegyetem: Eotvos Lorand Tudomanyegyetem Laboratory of Interfaces and Nanostructures HUNGARY
| | - Éva Kiss
- Eötvös Loránd Tudományegyetem: Eotvos Lorand Tudomanyegyetem Laboratory of Interfaces and Nanostructures HUNGARY
| | - Gabor London
- Research Centre for Natural Sciences Institute of Organic Chemistry Magyar tudósok körűtja 2. 1117 Budapest HUNGARY
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Dery S, Alshanski I, Mervinetsky E, Feferman D, Yitzchaik S, Hurevich M, Gross E. The influence of surface proximity on photoswitching activity of stilbene-functionalized N-heterocyclic carbene monolayers. Chem Commun (Camb) 2021; 57:6233-6236. [PMID: 34095904 DOI: 10.1039/d1cc02491d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Self-assembly of photo-responsive molecules is a robust technology for reversibly tuning the properties of functional materials. Herein, we probed the crucial role of surface-adsorbate interactions on the adsorption geometry of stilbene-functionalized N-heterocyclic carbenes (stilbene-NHCs) monolayers and its impact on surface potential. Stilbene-NHCs on Au film accumulated in a vertical orientation that enabled high photoisomerization efficiency and reversible changes in surface potential. Strong metal-adsorbate interactions led to flat-lying adsorption geometry of stilbene-NHCs on Pt film, which quenched the photo-isomerization influence on surface potential. It is identified that photo-induced response can be optimized by positioning the photo-active group in proximity to weakly-interacting surfaces.
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Affiliation(s)
- Shahar Dery
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Israel Alshanski
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Evgeniy Mervinetsky
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Daniel Feferman
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Shlomo Yitzchaik
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Mattan Hurevich
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
| | - Elad Gross
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel.
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Diez Cabanes V, Van Dyck C, Osella S, Cornil D, Cornil J. Challenges for Incorporating Optical Switchability in Organic-Based Electronic Devices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27737-27748. [PMID: 34105343 DOI: 10.1021/acsami.1c05489] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transistors operate by controlling the current flowing from a source to a drain electrode via a third electrode (gate), thus giving access to a binary treatment (ON/OFF or 0/1) of the signal currently exploited in microelectronics. Introducing a second independent lever to modulate the current would allow for more complex logic functions amenable to a single electronic component and hence to new opportunities for advanced electrical signal processing. One avenue is to add this second dimension with light by incorporating photochromic molecules in current organic-based electronic devices. In this Spotlight, we describe different concepts that have been implemented in organic thin films and in molecular junctions as well as some pitfalls that have been highlighted thanks to theoretical modeling.
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Affiliation(s)
- Valentin Diez Cabanes
- Laboratoire de Physique et Chimie Théoriques, Université de Lorraine & CNRS, 54000 Nancy, France
| | - Colin Van Dyck
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Silvio Osella
- Chemical and Biological Systems Simulation Lab, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warszawa, Poland
| | - David Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium
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Quintano V, Diez-Cabanes V, Dell’Elce S, Di Mario L, Pelli Cresi S, Paladini A, Beljonne D, Liscio A, Palermo V. Measurement of the conformational switching of azobenzenes from the macro- to attomolar scale in self-assembled 2D and 3D nanostructures. Phys Chem Chem Phys 2021; 23:11698-11708. [DOI: 10.1039/d1cp00740h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We compare the cis–trans conformational switching of commercial azobenzene molecules in different chemical environments, ranging from isolated molecules in liquid to attomolar-2D and macro-scale 3D self-assembled structures.
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Affiliation(s)
- Vanesa Quintano
- Institute of Organic Synthesis and Photoreactivity (ISOF) – (CNR)
- 40129 Bologna
- Italy
| | | | | | - Lorenzo Di Mario
- Division of Ultrafast Processes in Materials (FLASHit)
- Institute of Structure of Matter (ISM) – CNR
- 00133 Rome
- Italy
| | - Stefano Pelli Cresi
- Division of Ultrafast Processes in Materials (FLASHit)
- Institute of Structure of Matter (ISM) – CNR
- 00133 Rome
- Italy
| | - Alessandra Paladini
- Division of Ultrafast Processes in Materials (FLASHit)
- Institute of Structure of Matter (ISM) – CNR
- 00133 Rome
- Italy
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials
- University of Mons
- B-7000 Mons
- Belgium
| | - Andrea Liscio
- Institute for Microelectronics and Microsystems (IMM)
- National Research Council of Italy (CNR)
- 00133 Rome
- Italy
| | - Vincenzo Palermo
- Institute of Organic Synthesis and Photoreactivity (ISOF) – (CNR)
- 40129 Bologna
- Italy
- Department of Industrial and Materials Science
- Chalmers University of Technology
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Riaz S, Friedrichs G. Vibrational sum-frequency generation study of molecular structure, sterical constraints and nonlinear optical switching contrast of mixed alkyl-azobenzene self-assembled monolayers. Z PHYS CHEM 2020. [DOI: 10.1515/zpch-2020-1655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Abstract
Self-assembled monolayers (SAMs) of azobenzene (AB) functionalized alkyl thiols on gold diluted with simple alkyl thiols provide a straightforward way to photochromic surfaces with high and tunable photoswitching efficiency. Trans-cis isomerization of the AB molecule changes the physical properties of the surface, including the nonlinear optical (NLO) response. Vibrational sum-frequency generation (VSFG) spectroscopy as a nonlinear type of laser spectroscopy offers surface- and orientation-sensitive insight into the molecular structure of mixed SAMs. In this study, VSFG as well as ultraviolet-visible (UV/Vis) spectroscopy has been employed to investigate the morphology, molecular structure, and NLO response of mixed SAMs with systematically varied surface composition. Methylazobenzene (MeAB) has been used as the molecular switch with the methyl substituent serving as orientational VSFG marker. Both short-chain and long-chain alkyl thiol co-ligands have been used to gain insight into the interplay between SAM structure and sterical constraints that are known to limit the free switching volume. Underlining the dominating role of sterical effects for controlling photochromic properties, a strong inhibition of the photoswitching efficiency and NLO response has been observed for the SAMs with an alkyl thiol co-ligand long enough to spatially extend into the layer of the MeAB chromophore. Overall, with <12% signal change, the relative NLO switching contrasts remained low in all cases. VSFG spectral trends clearly revealed that the presumably higher photoswitching efficiency upon dilution with the co-ligand is counteracted by a loss of structural order of the chromophore.
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Affiliation(s)
- Saira Riaz
- Islamabad College for Girls , F-6/2 , Islamabad, 44000 , Pakistan
| | - Gernot Friedrichs
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel , Max-Eyth-Str. 1, 24118 , Kiel , Germany
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Lipomi DJ, Dhong C, Carpenter CW, Root NB, Ramachandran VS. Organic Haptics: Intersection of Materials Chemistry and Tactile Perception. ADVANCED FUNCTIONAL MATERIALS 2020; 30:1906850. [PMID: 34276273 PMCID: PMC8281818 DOI: 10.1002/adfm.201906850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Indexed: 05/06/2023]
Abstract
The goal of the field of haptics is to create technologies that manipulate the sense of touch. In virtual and augmented reality, haptic devices are for touch what loudspeakers and RGB displays are for hearing and vision. Haptic systems that utilize micromotors or other miniaturized mechanical devices (e.g., for vibration and pneumatic actuation) produce interesting effects, but are quite far from reproducing the feeling of real materials. They are especially deficient in recapitulating surface properties: fine texture, friction, viscoelasticity, tack, and softness. The central argument of this Progress Report is that to reproduce the feel of everyday objects requires chemistry: molecular control over the properties of materials and ultimately design of materials which can change these properties in real time. Stimuli-responsive organic materials, such as polymers and composites, are a class of materials which can change their oxidation state, conductivity, shape, and rheological properties, and thus might be useful in future haptic technologies. Moreover, the use of such materials in research on tactile perception could help elucidate the limits of human tactile sensitivity. The work described represents the beginnings of this new area of inquiry, in which the defining approach is the marriage of materials science and psychology.
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Affiliation(s)
- Darren J Lipomi
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Charles Dhong
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Cody W Carpenter
- Department of NanoEngineering and Program in Chemical Engineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448
| | - Nicholas B Root
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
| | - Vilayanur S Ramachandran
- Department of Psychology, University of California, San Diego, 9500 Gilman Drive, Mail Code 0109, La Jolla, CA 92093-0109
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