We pursue dynamic charge and occupancy modulation of silicon dangling bond sites on H-Si(100)-2 × 1 with a biased scanning tunneling microscope tip and demonstrate that the reactivity and mechanism of product formation of cyclobutylmethylketone (CBMK) on the surface at the active sites may be thus spatially regulated. Reactivity is observed to be dependent on the polarity between tip and surface while the area over which reactivity modulation is established scales according to the dopant concentration in the sample. We account for these observations with examination of the competition kinetics applicable to the CBMK/H-Si reaction and determine how said kinetics are affected by the charge state of DB sites associated with reaction initiation and propagation. Our experiments demonstrate a new paradigm in lithographic control of a self-assembly process on H-Si and reveal a variant to the well-known radical mediated chain reaction chemistry applicable to the H-Si surface where self-assembly is initiated with dative bond formation between the molecule and a DB site.
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http://dx.doi.org/10.1021/ja3017208 | DOI Listing |
ACS Nano
January 2025
School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.
Van der Waals electrode integration is a promising strategy to create nearly perfect interfaces between metals and 2D materials, with advantages such as eliminating Fermi-level pinning and reducing contact resistance. However, the lack of a simple, generalizable pick-and-place transfer technology has greatly hampered the wide use of this technique. We demonstrate the pick-and-place transfer of prefabricated electrodes from reusable polished hydrogenated diamond substrates without the use of any sacrificial layers due to the inherent low-energy and dangling-bond-free nature of the hydrogenated diamond surface.
View Article and Find Full Text PDFACS Nano
January 2025
School of Electrical Engineering, Korea University, Seoul 02841, Korea.
Artificial synapses for neuromorphic computing have been increasingly highlighted, owing to their capacity to emulate brain activity. In particular, solid-state electrolyte-gated electrodes have garnered significant attention because they enable the simultaneous achievement of outstanding synaptic characteristics and mass productivity by adjusting proton migration. However, the inevitable interface traps restrict the protons at the channel-electrolyte interface, resulting in the deterioration of synaptic characteristics.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
KISTEC (Kanagawa Institute of Industrial Science & Technology), 705-1, Shimoimaizumi, Ebina 243-0435, Japan.
In short-carbon-fiber-reinforced polyamide 66 articles shaped by 3D printing (3D-SCFRPA66), the interfaces between printed layers are often susceptible to damage, and the composite is excessively brittle. Therefore, a novel treatment for 3D-printed short-carbon-fiber-reinforced polyamide (3D-SCFRPA66) using homogeneous low-potential electron beam irradiation (HLEBI) to enhance tensile properties was investigated. In 3D-SCFRPA66 samples, ductility was measured based on the following parameters: strain at tensile strength (corresponding to homogeneous deformation) () and resistance energy to homogeneous deformation, a measure of toughness (), which were both substantially increased.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Shear thinning of associative polymers is tied to bond breakage under deformation and retraction of dangling chains, as predicted by transient network theories. However, an in-depth understanding of the molecular mechanisms is limited by our ability to measure the molecular states of the polymers during deformation. Herein, utilizing a custom-built rheo-fluorescence setup, bond dissociation in model end-linked associative polymers is quantified in real time with nonlinear shear deformation based on a fluorescence quench transition when phenanthroline ligands bind with Ni.
View Article and Find Full Text PDFNano Lett
December 2024
Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
Nanoconfined water exhibits astonishing properties that offer new opportunities in physics, biology and technology like energy-storage applications. Here we study such nanoconfined water using molecular dynamics simulations to elucidate the structure and dynamics of water monolayers in graphene-based slit pores. The significant population of dangling (or free) O-H bonds pointing toward the two confining walls, leads to topological frustration in the hydrogen bond network.
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