5 research outputs found

    Compiled linescanner images of sediment core SO256_2-2

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    Intercalation of molecules into layered materials is actively researched in materials science, chemistry, and nanotechnology, holding promise for the synthesis of van der Waals heterostructures and encapsulated nanoreactors. However, the intercalation of organic molecules that exhibit physical or chemical functionality remains a key challenge to date. In this work, we present the synthesis of heterostructures consisting of porphines sandwiched between a Cu(111) substrate and an insulating hexagonal boron nitride (<i>h</i>-BN) monolayer. We investigated the energetics of the intercalation, as well as the influence of the capping <i>h</i>-BN layer on the behavior of the intercalated molecules using scanning probe microscopy and density functional theory calculations. While the self-assembly of the molecules is altered upon intercalation, we show that the intrinsic functionalities, such as switching between different porphine tautomers, are preserved. Such insulator/molecule/metal structures provide opportunities to protect organic materials from deleterious effects of atmospheric environment, can be used to control chemical reactions through spatial confinement, and give access to layered materials based on the ample availability of synthesis protocols provided by organic chemistry

    Layered Insulator/Molecule/Metal Heterostructures with Molecular Functionality through Porphyrin Intercalation

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    Intercalation of molecules into layered materials is actively researched in materials science, chemistry, and nanotechnology, holding promise for the synthesis of van der Waals heterostructures and encapsulated nanoreactors. However, the intercalation of organic molecules that exhibit physical or chemical functionality remains a key challenge to date. In this work, we present the synthesis of heterostructures consisting of porphines sandwiched between a Cu(111) substrate and an insulating hexagonal boron nitride (<i>h</i>-BN) monolayer. We investigated the energetics of the intercalation, as well as the influence of the capping <i>h</i>-BN layer on the behavior of the intercalated molecules using scanning probe microscopy and density functional theory calculations. While the self-assembly of the molecules is altered upon intercalation, we show that the intrinsic functionalities, such as switching between different porphine tautomers, are preserved. Such insulator/molecule/metal structures provide opportunities to protect organic materials from deleterious effects of atmospheric environment, can be used to control chemical reactions through spatial confinement, and give access to layered materials based on the ample availability of synthesis protocols provided by organic chemistry

    Probing the Site-Dependent Kondo Response of Nanostructured Graphene with Organic Molecules

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    TCNQ molecules are used as a sensitive probe for the Kondo response of the electron gas of a nanostructured graphene grown on Ru(0001) presenting a moiré pattern. All adsorbed molecules acquired an extra electron by charge transfer from the substrate, but only those adsorbed in the FCC-Top areas of the moiré show magnetic moment and Kondo resonance in the STS spectra. DFT calculations trace back this behavior to the existence of a surface resonance in the low areas of the graphene moiré, whose density distribution strongly depends on the stacking sequence of the moiré area and effectively quenches the magnetic moment for HCP-Top sites

    Adsorption Conformation and Lateral Registry of Cobalt Porphine on Cu(111)

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    The tetrapyrrole macrocycle of porphine is the common core of all porphyrin molecules, an interesting class of π-conjugated molecules with relevance in natural and artificial systems. The functionality of porphines on a solid surface can be tailored by the central metal atom and its interaction with the substrate. In this study, we present a local adsorption geometry determination for cobalt porphine on Cu(111) by means of complementary scanning tunneling microscopy, high-resolution X-ray photoelectron spectroscopy, X-ray standing wave measurements, and density functional theory calculations. Specifically, the Co center was determined to be at an adsorption height of 2.25 ± 0.04 Å occupying a bridge site. The macrocycle adopts a moderate asymmetric saddle-shape conformation, with the two pyrrole groups that are aligned perpendicular to the densely packed direction of the Cu(111) surface tilted away from the surface plane

    Corrugation in the Weakly Interacting Hexagonal-BN/Cu(111) System: Structure Determination by Combining Noncontact Atomic Force Microscopy and X‑ray Standing Waves

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    Atomically thin hexagonal boron nitride (<i>h</i>-BN) layers on metallic supports represent a promising platform for the selective adsorption of atoms, clusters, and molecular nanostructures. Specifically, scanning tunneling microscopy (STM) studies revealed an electronic corrugation of <i>h</i>-BN/Cu­(111), guiding the self-assembly of molecules and their energy level alignment. A detailed characterization of the <i>h</i>-BN/Cu­(111) interface including the spacing between the <i>h</i>-BN sheet and its supportelusive to STM measurementsis crucial to rationalize the interfacial interactions within these systems. To this end, we employ complementary techniques including high-resolution noncontact atomic force microscopy, STM, low-energy electron diffraction, X-ray photoelectron spectroscopy, the X-ray standing wave method, and density functional theory. Our multimethod study yields a comprehensive, quantitative structure determination including the adsorption height and the corrugation of the sp<sup>2</sup> bonded <i>h</i>-BN layer on Cu(111). Based on the atomic contrast in atomic force microscopy measurements, we derive a measurable–hitherto unrecognized–geometric corrugation of the <i>h-</i>BN monolayer. This experimental approach allows us to spatially resolve minute height variations in low-dimensional nanostructures, thus providing a benchmark for theoretical modeling. Regarding potential applications, <i>e.g.</i>, as a template or catalytically active support, the recognition of <i>h</i>-BN on Cu(111) as a weakly bonded and moderately corrugated overlayer is highly relevant
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