The concept of nanoparticle-mediated electron transfer (eT) across insulating thin films was elucidated theoretically by Allongue and Chazalviel in 2011. In their model, metal nanoparticles (NPs) are immobilized atop passivating, self-assembled monolayers (SAMs). They found that under certain conditions, related to the thickness of the SAM and the size of the NPs, efficient faradaic oxidation and reduction reactions could proceed at the NP surface. In the absence of NPs, however, eT was suppressed by the insulating SAM thin films. Allongue and Chazalviel concluded that, within certain bounds, eT is mediated by fast tunneling between the conductive electrode and the metal NPs, while the kinetics of the redox reaction are controlled by the NPs. This understanding has been confirmed using a variety of experimental models. The theory is based on electron tunneling; therefore, the nature of the intervening medium (the insulator in prior studies) should not affect the eT rate. In the present manuscript, however, we show that the theory breaks down under certain electrochemical conditions when the medium between conductors is an -type semiconductor. Specifically, we find that in the presence of either Au or Pt NPs immobilized on a thin film of TiO, CO electrooxidation does not proceed. In contrast, the exact same systems lead to the efficient reduction of oxygen. At present, we are unable to explain this finding within the context of the model of Allongue and Chazalviel.
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http://dx.doi.org/10.3390/nano12050855 | DOI Listing |
Sci Rep
January 2025
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.
Vanadium dioxide ([Formula: see text]) is a favorable material platform of modern optoelectronics, since it manifests the reversible temperature-induced insulator-metal transition (IMT) with an abrupt and rapid changes in the conductivity and optical properties. It makes possible applications of such a phase-change material in the ultra-fast optoelectronics and terahertz (THz) technology. Despite the considerable interest to this material, data on its broadband electrodynamic response in different states are still missing in the literature.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Leibniz-Institut fur Festkorper- und Werkstoffforschung Dresden eV, Helmholtzstraße 20, 01069, Dresden, GERMANY.
This study presents the first successful demonstration of growing elemental bismuth (Bi) thin films via thermal atomic layer deposition (ALD) using Bi(NMe2)3 as the precursor and Sb(SiMe3)3 as the co-reactant. The films were deposited at a relatively low temperature of 100 °C, with a growth per cycle (GPC) of 0.31-0.
View Article and Find Full Text PDFNanotechnology
January 2025
School of Electrical Engineering, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xianning West Road No.28 Xi'an Shannxi Province, Xi'an, Shaanxi, 710049, CHINA.
HfO-based ferroelectric (FE) thin films have gained considerable interest for memory applications due to their excellent properties. However, HfO₂-based FE films face significant reliability challenges, especially the wake-up and fatigue effects, which hinder their practical application. In this work, we fabricated 13.
View Article and Find Full Text PDFNanoscale
January 2025
Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Giuseppe Moruzzi 13, 56124 Pisa, Italy.
The development of chiral organic materials with strong non-reciprocal chiroptical features may have major implications for cutting-edge technological applications. In this work, a new synthesized chiral 1,4-diketo-3,6-dithienylpyrrolo[3,4-]pyrrole dye, bearing two ()-3,7-dimethyl-1-octyl alkyl chains on the lactam moieties and functionalized with two lateral 9-anthracenyl π-conjugated units, exhibited strong non-reciprocal chiroptical properties in thin films, with some important differences between samples prepared by drop casting and spin coating. A detailed study was performed to unravel the intimate structure-property relationship, involving computational analysis, different microscopy techniques and synchrotron radiation Mueller matrix polarimetry imaging (SR-MMP) investigation.
View Article and Find Full Text PDFJ Appl Crystallogr
January 2024
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, USA.
Neutron reflectometry (NR) is a powerful technique for interrogating the structure of thin films at interfaces. Because NR measurements are slow and instrument availability is limited, measurement efficiency is paramount. One approach to improving measurement efficiency is active learning (AL), in which the next measurement configurations are selected on the basis of information gained from the partial data collected so far.
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