The long-term cycling of anode-free Li-metal cells (i.e., cells where the negative electrode is in situ formed by electrodeposition on an electronically conductive matrix of lithium sourced from the positive electrode) using a liquid electrolyte is affected by the formation of an inhomogeneous solid electrolyte interphase (SEI) on the current collector and irregular Li deposition.
View Article and Find Full Text PDFSecuring a semiconducting bandgap is essential for applying graphene layers in switching devices. Theoretical studies have suggested a created bulk bandgap in a graphene layer by introducing an asymmetry between the A and B sub-lattice sites. A recent transport measurement demonstrated the presence of a bandgap in a graphene layer where the asymmetry was introduced by placing a graphene layer on a hexagonal boron nitride (h-BN) substrate.
View Article and Find Full Text PDFMethods to decouple epitaxial graphene from metal substrates have been extensively studied, with anticipation of observing unperturbed Dirac cone properties, but its local electronic structures were rarely studied. Here, we investigated the local variations of Dirac cones recovered using oxygen intercalation applied to epitaxial graphene on Ru(0001) using scanning tunneling microscopy and spectroscopy (STM and STS). New V-shaped features, which appear in the STS data at the oxygen-intercalated graphene regions, are attributed to the signatures of recovered Dirac cones.
View Article and Find Full Text PDFThe electronic structures of self-assembled hybrid chains comprising Ag atoms and organic molecules were studied using scanning tunneling microscopy (STM) and spectroscopy (STS) in parallel with density functional theory (DFT). Hybrid chains were prepared by catalytic breaking of Br-C bonds in 4,4″-dibromo-p-terphenyl molecules, followed by spontaneous formation of Ag-C bonds on Ag(111). An atomic model was proposed for the observed hybrid chain structures.
View Article and Find Full Text PDFAtomically flat thin films of Bi(2)Se(3) were grown on Au(111) metal substrate using molecular beam epitaxy. Hexagonal atomic structures and quintuple layer steps were observed at the surfaces of grown films using scanning tunneling microscopy. Multiple sharp peaks from (003) family layers were characterized by x-ray diffraction measurements.
View Article and Find Full Text PDFChem Commun (Camb)
November 2011
Intermolecular structures of porous two-dimensional supramolecular networks are studied using scanning tunnelling microscopy combined with density functional theory calculations. The local configurations of halogen bonds in polymorphic porous supramolecular networks are directly visualized in support of previous bulk crystal studies.
View Article and Find Full Text PDFChiral phase transitions were studied in a self-assembled 2,6-dibromoanthraquinones supramolecular system prepared on Au(111) using scanning tunneling microscopy. As the molecules were deposited at about 150 K, they formed heterochiral chevron structures (a racemate) consisting of two alternating prochiral molecular rows. When the as-deposited sample was warmed to 300 K followed by cooling to 80 K, phase-separated homochiral structures (a conglomerate), as well as the chevron structures, were observed.
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