Influence of metal–support interaction on the surface structure of gold nanoclusters deposited on native SiOx/Si substrates

Portale, Giuseppe; Sciortino, Luisa; Albonetti, Cristiano; Giannici, Francesco; Martorana, Antonino; Bras, Wim; Biscarini, Fabio; Longo, Alessandro

doi:10.1039/c3cp54847c

Cited by 25 publications

(26 citation statements)

References 52 publications

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“…10(a) and 10(b) exhibit a single-broad Debye-Scherrer like ring, suggesting that the thin-film structure consists of ZrMc clusters arranged in a 3-D disordered manner. 38 Nevertheless, the scattering ring shows some anisotropy suggesting a preferential packing in the direction parallel to the Si substrate, a common arrangement of disordered multilayered nanoparticles. 39 The average spacing among clusters along the q y horizontal direction calculated according to the Bragg's law from the position of the scattering maxima in the intensity cuts reported in Fig.…”

Section: Origin Of the Solubility Switchmentioning

confidence: 99%

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

Baljozović

Portale

et al. 2019

J. Micro/Nanolith. MEMS MOEMS

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Background: Inorganic resists show promising performances in extreme ultraviolet (EUV) lithography. Yet, there is a need for understanding the exact chemical mechanisms induced by EUV light on these materials. Aim: To gain knowledge on the EUV chemistry of inorganic resists, we investigate hybrid inorganic-organic molecular compounds, metal oxoclusters (MOCs). Their molecular nature allows for the monitoring of specific structural changes by means of spectroscopy and thus for the elucidation of the mechanisms behind pattern formation. Approach: We compare the sensitivity of MOCs based on Zr and Hf, and methacrylate ligands as EUV resists. The chemical and structural changes causing the solubility switch were investigated by ex situ x-ray spectroscopy, infrared spectroscopy, ultraviolet-visible spectroscopy, and grazing incidence x-ray scattering. Results: Higher sensitivity was detected for the Hf-based material, in line with its higher absorptivity. A small fraction of the carboxylate ligands is lost at doses that yield solubility contrast, whereas aggregation of the inorganic clusters was not observed. Conclusions: These results provide evidence that, although the mechanism of solubility switch in these materials starts with decarboxylation reactions, it mainly proceeds through cross linking of the organic shells instead of aggregation of the inorganic clusters.

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Section: Origin Of the Solubility Switchmentioning

confidence: 99%

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

Baljozović

Portale

et al. 2019

J. Micro/Nanolith. MEMS MOEMS

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“…The GISAXS intensity scattered at low angles along the parallel q y direction provides quantitative information about the nanoparticle lateral dimensions (Figure A). For all the samples, a strong intensity upturn at low q y values is recorded for α i <0.2°, suggesting that the signal is dominated by scattering from the larger Ag NPs located at the film surface (already observed by TEM in Figure A) . For α i >0.2°, the intensity upturn decreases and the intensity at low q y becomes flat in the log‐log plot for α i ≫α c of silver (where α c =0.3° is the critical angle for bulk silver), suggesting that the contribution from the nanostructures present on the surface becomes negligible with respect to the structures inside the network.…”

Section: Resultsmentioning

confidence: 59%

On the Dimensional Control of 2 D Hybrid Nanomaterials

Longo

Mulder

Kuringen

et al. 2017

Chemistry A European J

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Thermotropic smectic liquid crystalline polymers were used as a scaffold to create organic/inorganic hybrid layered nanomaterials. Different polymers were prepared by photopolymerizing blends of a hydrogen bonded carboxylic acid derivative and a 10 % cross‐linker of variable length in their liquid crystalline phase. Nanopores with dimensions close to 1 nm were generated by breaking the hydrogen bonded dimers in a high pH solution. The pores were filled with positively charged silver (Ag) ions, resulting in a layered silver(I)‐polymeric hybrid material. Subsequent exposure to a NaBH4 reducing solution allowed for the formation of supported hybrid metal/organic films. In the bulk of the film the dimension of the Ag nanoparticles (NPs) was regulated with subnanometer precision by the cross‐linker length. Ag nanoparticles with an average size of 0.9, 1.3, and 1.8 nm were produced inside the nanopores thanks to the combined effect of spatially confined reduction and stabilization of the nanoparticles by the polymer carboxylic groups. At the same time, strong Ag migration occurred in the surface region, resulting in the formation of a nanostructured metallic top layer composed of large (10–20 nm) NPs.

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“…[1][2][3][4][5] The property of metal nanoclusters is one of the major factors in determining catalytic performance. [6][7][8][9] However, the nature of support materials often has a substantial influence on the adsorption ability and catalytic activity of metal nanoclusters.…”

Section: Introductionmentioning

confidence: 99%

Effect of graphene with nanopores on metal clusters

Zhou

Chen

Wang

et al. 2015

Phys. Chem. Chem. Phys.

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Porous graphene, which is a novel type of defective graphene, shows excellent potential as a support material for metal clusters. In this work, the stability and electronic structures of metal clusters (Pd, Ir, and Rh) supported on pristine graphene and graphene with different sizes of nanopores were investigated using first-principles density functional theory (DFT) calculations. Then, CO adsorption and oxidation on the Pd-graphene system were chosen to evaluate its catalytic performance. Graphene with nanopores can strongly stabilize the metal clusters and cause a substantial downshift of the d-band center of the metal clusters, thus decreasing CO adsorption. All binding energies, d-band centers, and adsorption energies show a linear change with the size of the nanopore: a bigger size of the nanopore corresponds to stronger bonding of metal clusters with graphene, lower downshift of the d-band center, and weaker CO adsorption. By using a suitable size nanopore, Pd clusters supported on graphene will have similar CO and O2 adsorption abilities, thus leading to superior CO tolerance. The DFT calculated reaction energy barriers show that graphene with nanopores is a superior catalyst for CO oxidation reaction. These properties can play an important role in instructing graphene-supported metal catalyst preparation to prevent the diffusion or agglomeration of metal clusters and enhance the catalytic performance.

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Influence of metal–support interaction on the surface structure of gold nanoclusters deposited on native SiOx/Si substrates

Cited by 25 publications

References 52 publications

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

On the Dimensional Control of 2 D Hybrid Nanomaterials

Effect of graphene with nanopores on metal clusters

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