A5075100311- Molecular Junctions and Nanostructures
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Surface Chemistry and Catalysis
- Force Microscopy Techniques and Applications
- Quantum and electron transport phenomena
- Surface and Thin Film Phenomena
- Electrocatalysts for Energy Conversion
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Electrochemical Analysis and Applications
- Advanced Photocatalysis Techniques
- Porphyrin and Phthalocyanine Chemistry
- Electron and X-Ray Spectroscopy Techniques
- Quantum Dots Synthesis And Properties
- Quantum-Dot Cellular Automata
- Semiconductor materials and devices
- Cyclopropane Reaction Mechanisms
- Nanomaterials for catalytic reactions
- TiO2 Photocatalysis and Solar Cells
- Nanowire Synthesis and Applications
- nanoparticles nucleation surface interactions
- Electronic and Structural Properties of Oxides
- Phase Equilibria and Thermodynamics
- Nanofabrication and Lithography Techniques
- Asymmetric Hydrogenation and Catalysis
Columbia University
2016-2020
AREA Science Park
2013-2017
University of Trieste
2015-2017
Istituto Officina dei Materiali
2015
Institute of Nanotechnology
2015
The geometry and bonding of N-heterocyclic carbenes to metal surfaces depends on the substituents N-atoms.
Stable organic radicals have potential applications for building spintronic devices. To fulfill this potential, the interface between and metal electrodes must be well characterized. Here, through a combined effort that includes synthesis, scanning tunneling microscopy, X-ray spectroscopy, single-molecule conductance measurements, we comprehensively probe electronic interaction gold benchtop stable radical—the Blatter radical. We find despite its open-shell character having half-filled...
Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some as functional elements of molecular-scale devices. Here we investigate the impact configurational degrees freedom ferrocene derivative on its single-molecule junction conductance. Measurements indicate conductance...
The molecule/metal interface is the key element in charge injection devices. It can be generally defined by a monolayer-thick blend of donor and/or acceptor molecules contact with metal surface. Energy barriers for electron and hole are determined offset from HOMO (highest occupied) LUMO (lowest unoccupied) molecular levels this layer respect to Fermi level electrode. However, alignment not easy elucidate complex multicomponent, systems. We demonstrate that core-level photoemission...
Self-assembled monolayers (SAMs) formed using N-heterocyclic carbenes (NHCs) have recently emerged as thermally and chemically ultrastable alternatives to those from thiols. The rich chemistry strong σ-donating ability of NHCs offer unique prospects for applications in nanoelectronics, sensing, electrochemistry. Although stable SAMs, free are notoriously reactive, making their electronic characterization challenging. Here we report the first investigation electron transport across single...
We investigate light-induced conductance enhancement in single-molecule junctions via photon-assisted transport and hot-electron transport. Using 4,4′-bipyridine bound to Au electrodes as a prototypical junction, we report 20–40% under illumination with 980 nm wavelength radiation. probe the effects of subtle changes transmission function on light-enhanced current show that discrete variations binding geometry result 10% change enhancement. Importantly, prove theoretically steady-state...
Single-molecule conductance measurements have focused primarily on organic molecular systems. Here, we carry out scanning tunneling microscope-based break-junction a series of metal chalcogenide Co6Se8 clusters capped with conducting ligands varying lengths. We compare these those individual free and find that the different decay constants increasing ligand length. also show, through in two solvents, 1-bromonaphthalene 1,2,4-trichlorobenzene, depends solvent environment. discuss several...
Metal-free porphyrin molecules adsorb on the rutile TiO2(110) surface with their pyrrolic nitrogen atoms atop O-bridge rows, whereas iminic capture two additional hydrogen atoms. Hydrogenation occurs spontaneously at room temperature, irrespective of distance polypyrrolic macrocycle from surface, as varied by changing functionalization.
In this work, we show the possibility of tailoring molecular arrangement, as well chemical and structural modifications, porphyrins at monolayer saturation coverage on TiO2(110) by synchrotron photoemission spectroscopy, electron diffraction, STM topography, DFT calculations. Free-base tetraphenylporphyrins (2H-TPP) adsorb oxygen rows, where they can spontaneously capture two additional hydrogen atoms their iminic nitrogens (4H-TPP). Both 2H-TPP 4H-TPP molecules aggregate into a commensurate...
The surface reduction of rutile TiO2(110) generates a state in the band gap whose excess electrons are spread among multiple sites, making conductive and reactive. charge extraction, hence catalytic properties, depends critically on spatial extent redistribution, which has been hitherto probed by small molecules that recombine at oxygen vacancy (Ovac) sites. We demonstrate valence resonant photoemission (RESPES) very general extraction mechanism from reduced to an extended electron-acceptor...
We have studied the deposition of perylene-tetracarboxylic-diimide, PTCDI, on rutile (1 × 1)-TiO2(110) surface. At variance with other polyaromatic hydrocarbons, like acenes, PTCDI displays a significant interaction this dielectric substrate. moderate substrate temperature (∼400 K), first layer molecules aggregate into two-dimensional islands corresponding to 5) commensurate phase. According our surface diffraction, STM, and NEXAFS studies, accommodates one molecule per unit cell, atop each...
We demonstrate the thermal stability up to 450 °C of a titanium(iv)-porphyrin monolayer grown on rutile TiO2(110) surface. Starting from film metal-free tetra-phenyl-porphyrin, 2HTPP, deposited at room temperature, we show that, beyond self-metalation reaction 150°-200 °C, second phase transition takes place ∼350 °C. Using surface diffraction and microscopy, observe change symmetry (2 × 4)-obliq 6)-rect. Core level photoemission indicates that chemical states both molecular tetrapyrrolic...
We have studied the interaction of perylene, a prototypical organic molecule, on TiO2(110)-(1 × 1) surface at different coverages by an adequate combination ultrahigh vacuum STM and UPS techniques, together with accurate "many-body" corrected ab initio calculations. show that molecular coupling adsorption configuration strongly depend coverage. At submonolayer coverage, is dominated van der Waals substrate attraction, which keeps molecules in troughs between adjacent oxygen rows. this...
Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some as functional elements of molecular-scale devices. Here we investigate the impact configurational degrees freedom ferrocene derivative on its single-molecule junction conductance. Measurements indicate conductance...