Manipulating double-decker molecules at the liquid-solid interface

We have used a scanning tunneling microscope to manipulate heteroleptic phthalocyaninato, naphthalocyaninato, porphyrinato double-decker molecules at the liquid/solid interface between 1-phenyloctane solvent and graphite. We employed nano-grafting of phthalocyanines with eight octyl chains to place these molecules into a matrix of heteroleptic double-decker molecules; the overlayer structure is epitaxial on graphite. We have also used nano-grafting to place double-decker molecules in matrices of single-layer phthalocyanines with octyl chains. Rectangular scans with a scanning tunneling microscope at low bias voltage resulted in the removal of the adsorbed doubledecker molecular layer and substituted the double-decker molecules with bilayer-stacked phthalocyanines from phenyloctane solution. Single heteroleptic double-decker molecules with lutetium sandwiched between naphthalocyanine and octaethylporphyrin were decomposed with voltage pulses from the probe tip; the top octaethylporphyrin ligand was removed and the bottom naphthalocyanine ligand remained on the surface. A domain of decomposed molecules was formed within the double-decker molecular domain, and the boundary of the decomposed molecular domain self-cured to become rectangular. We demonstrated a molecular “sliding block puzzle” with cascades of double-decker molecules on the graphite surface

Ion Current Oscillation in Glass Nanopipettes

Ion currents detected by glass nanopipettes in solutions depended on the diameters of pipettes and ion species in the solutions. The ion current oscillation with frequency of 2.7 mHz was observed using the pipet with inner diameter of 50 nm in 0.1 M KCl solution. However, nonoscillatory currents were observed using the same pipet in 0.1 M KOH and HCl solutions or using pipettes with inner diameters of 15 nm, 500 nm, and 0.7 mm in 0.1 M KCl solution. Oscillation of the double layer thickness due to the change of ion concentration in the nanopipette perturbs the path of the ion current through the bulk layer, which results in the nonlinear current oscillation