Publications by authors named "K Leifer"

Graphene exhibits promise in gas detection applications despite its limited selectivity. Functionalization with fluorine atoms offers a potential solution to enhance selectivity, particularly towards ammonia (NH+) molecules. This article presents a study on electron-beam fluorinated graphene (FG) and its integration into gas sensor platforms.

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The need to acquire multiple angle-resolved electron energy loss spectra (EELS) is one of the several critical challenges associated with electron magnetic circular dichroism (EMCD) experiments. If the experiments are performed by scanning a nanometer to atomic-sized electron probe on a specific region of a sample, the precision of the local magnetic information extracted from such data highly depends on the accuracy of the spatial registration between multiple scans. For an EMCD experiment in a 3-beam orientation, this means that the same specimen area must be scanned four times while keeping all the experimental conditions same.

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Polymer-assisted wet transfer of chemical vapor deposited (CVD) graphene has achieved great success towards the true potential for large-scale electronic applications, while the lack of an efficient polymer removal method has been regarded as a crucial factor for realizing high carrier mobility in graphene devices. Hereby, we report an efficient and facile method to clean polymer residues on graphene surface by merely employing solvent mixture of isopropanol (IPA) and water (HO). Raman spectroscopy shows an intact crystal structure of graphene after treatment, and the x-ray photoelectron spectroscopy indicates a significant decrease in the C-O and C=O bond signals, which is mainly attributed to the removal of polymer residues and further confirmed by subsequent atomic force microscopy analysis.

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Graphene has stimulated great enthusiasm in a variety of fields, while its chemically inert surface still remains challenging for functionalization towards various applications. Herein, we report an approach to fabricate non-covalently functionalized graphene by employing π-π stacking interactions, which has potentialities for enhanced ammonia detection. 5,5'-Di(4-biphenylyl)-2,2'-bithiophene (BP2T) molecules are used in our work for the non-covalent functionalization through strong π-π interactions of aromatic structures with graphene, and systematic investigations by employing various spectroscopic and microscopic characterization methods confirm the successful non-covalent attachment of the BP2T on the top of graphene.

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Molecular electronic devices based on few and single-molecules have the advantage that the electronic signature of the device is directly dependent on the electronic structure of the molecules as well as of the electrode-molecule junction. In this work, we use a two-step approach to synthesise functionalized nanomolecular electronic devices (nanoMoED). In first step we apply an organic solvent-based gold nanoparticle (AuNP) synthesis method to form either a 1-dodecanethiol or a mixed 1-dodecanethiol/-tetraphenyl ether substituted 1-dodecanethiol ligand shell.

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