Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

Schlicke, Hendrik; Schröder, Jan; Trebbin, Martin; Petrov, Alexey M.; Ijeh, Michael; Weller, Horst; Voßmeyer, Tobias

doi:10.1088/0957-4484/22/30/305303

Cited by 44 publications

(127 citation statements)

References 32 publications

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“…Their thicknesses, which are listed in Table 1, were determined by AFM measurements as described earlier. 24 A typical AFM scan and height profile used for determining the film thickness is povided in the Supporting Information ( Figure S4). The average roughness of GNP/NDT films prepared following the layer-by-layer spin-coating method was investigated in an earlier study, yielding a value of R a = 0.47 nm.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Elastic and Viscoelastic Properties of Cross-Linked Gold Nanoparticles Probed by AFM Bulge Tests

Schlicke¹,

Leib²,

Petrov³

et al. 2014

J. Phys. Chem. C

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To enable applications of nanoparticle films in flexible electronics, actuators, and sensors, their mechanical properties are of critical concern. Here, we demonstrate that the elastic and viscoelastic properties of covalently cross-linked gold nanoparticles (GNPs) can be probed using AFM bulge tests. For this purpose 30−60 nm thick films consisting of 1,9-nonanedithiol (NDT) cross-linked GNPs (3.8 nm core diameter) were transferred onto substrates with ∼100 μm circular apertures. The resulting freestanding membranes were bulged by applying pressure differences of up to 10 kPa, and the deflection was measured by intermittent contact atomic force microscopy (AFM). Analyzing the pressure-deflection data using the spherical cap model, either by taking into account the peak deflection values or the measured arc profiles of the bulge, yielded 2.3 ± 0.3 and 2.7 ± 0.4 GPa for Young's modulus, respectively. When cycling the stress−strain measurements at overpressures up to 2.4 kPa, hysteresis was observed and assigned to viscoelastic effects. Creep tests performed at a pressure of 2 kPa revealed both viscoelastic retardation (time constant: 3.3 × 10 −3 s −1 ) and nonrecoverable relaxation (creep rate: 9.0 × 10 −8 s −1 ). Several membranes resisted pressures up to 10 kPa without fracturing, indicating that the ultimate biaxial tensile strength of the films was above ∼30 MPa. ■ INTRODUCTIONThin films consisting of ligand-stabilized or cross-linked gold nanoparticles (GNPs) have received considerable scientific attention during the past two decades, and various applications have been demonstrated. For example, transduction elements based on thin GNP films have enabled the fabrication of novel resistive strain gauges, 1−4 touch sensors, 5,6 and chemiresistors. 7 In these sensors the transduction mechanism is based on changes in the interparticle distances, due to either forceinduced strain or sorption-induced swelling. Because the tunneling current between neighboring nanoparticles is exponentially related to their distance, these sensors can afford extremely high sensitivities. Further, nanoparticle networks have great potential for the implementation in next-generation flexible electronics. Very recently, Kotov and co-workers 8 reported on stretchable conductors made from GNP−polyurethane composites enabling electrical tunability of mechanical properties by dynamic self-organization of the nanoparticles under stress.Obviously, the performance of sensors and flexible electronics based on nanoparticle composites critically depends on their specific mechanical properties, e.g., elasticity, viscoelasticity, and ultimate strength. To some extent, these properties have been studied by nanoindentation 9 and forcedeflection measurements employing atomic force microscopes (AFMs). 10−12 In conventional nanoindentation experiments the indenter tip is pressed into the substrate-supported specimen, and the force−distance data are analyzed to extract the material's hardness and reduced elastic modulus. 13 Recently, the micromechanical p...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Elastic and Viscoelastic Properties of Cross-Linked Gold Nanoparticles Probed by AFM Bulge Tests

Schlicke¹,

Leib²,

Petrov³

et al. 2014

J. Phys. Chem. C

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“…create NP films as vapor-sensing platform [20,21]. Longer dithiol linkers can yield very stable aggregates, that can be moulded into arbitrary shapes as shown in a study by Klajn et al [22].…”

Section: Introductionmentioning

confidence: 99%

Impact of the Crosslinker’s Molecular Structure on the Aggregation of Gold Nanoparticles

Deffner

Schulz²,

Lange³

2016

Zeitschrift Für Physikalische Chemie

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Abstract:We studied the aggregation of AuNP induced by small aromatic molecules under different conditions. In water, the aggregation was found to be difficult to control. Phase transfer of the particles into toluene by using oleylamine as a ligand allows for a more controlled and reliable synthesis. Using nonane-1,9-dithiol as a control, our experiments demonstrate that the molecular structure of the linker has a decisive influence on the aggregation. Aromatic dithiols yielded spherical aggregates in the range of 100 nm, whereas the aliphatic linker produced large aggregates in the µm range. The length of the aromatic linker (2 vs. 3 phenylene units) strongly affected aggregation kinetics and the structure of the produced aggregates. With UV/Vis and DLS based experiments it was possible to distinguish the process of ligand layer formation and aggregation. Our results will help to develop syntheses of defined spherical aggregates and possibly more complex structures.

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“…Upon application of multiples of these deposition cycles, the layer thickness can be adjusted in the range of 20− 100 nm. 17 The GNP films exhibited characteristic UV/vis absorption spectra featuring a pronounced plasmon band and ohmic charge-transport behavior with conductivities of around 0.1 S cm −1 . 17 Representative UV/vis spectra and IV data can be found in the SI.…”

mentioning

confidence: 99%

“…17 The GNP films exhibited characteristic UV/vis absorption spectra featuring a pronounced plasmon band and ohmic charge-transport behavior with conductivities of around 0.1 S cm −1 . 17 Representative UV/vis spectra and IV data can be found in the SI. Transmission electron microscopy (TEM) micrographs of a (38 ± <1)-nm-thick 1,6-hexanedithiol (6DT)-interlinked GNP membrane transferred to a carbon-coated TEM substrate are depicted in Figure 1e,f and reveal the membrane's nanoscale granular morphology.…”

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confidence: 99%

Freestanding Membranes of Cross-Linked Gold Nanoparticles: Novel Functional Materials for Electrostatic Actuators

Schlicke¹,

Battista²,

Kunze³

et al. 2015

ACS Appl. Mater. Interfaces

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Their tunable electrical, optical, and mechanical properties make freestanding membranes of organically cross-linked gold nanoparticles (GNPs) interesting materials for applications in micro- and nanoelectromechanical systems. Here, we demonstrate the application of α,ω-alkanedithiol-cross-linked GNP membranes as electrostatically driven actuators. The devices were fabricated by depositing these membranes (thickness 29-45 nm) onto cylindrical cavities (diameter ∼200 μm; depth ∼8-15 μm), which were lithographically patterned in a SU-8 resist. Applying voltages of up to ±40 V across the membrane and the silicon substrate deflected the membranes by several hundreds of nanometers, as measured by atomic force microscopy, confocal microscopy, and interferometry. A simple electrostatic model, which takes into account the membranes' mechanical properties, was used to interpret the experimental data.

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Freestanding films of crosslinked gold nanoparticles prepared via layer-by-layer spin-coating

Cited by 44 publications

References 32 publications

Elastic and Viscoelastic Properties of Cross-Linked Gold Nanoparticles Probed by AFM Bulge Tests

Elastic and Viscoelastic Properties of Cross-Linked Gold Nanoparticles Probed by AFM Bulge Tests

Impact of the Crosslinker’s Molecular Structure on the Aggregation of Gold Nanoparticles

Freestanding Membranes of Cross-Linked Gold Nanoparticles: Novel Functional Materials for Electrostatic Actuators

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