159 research outputs found
Benzotrithiophene-Based Donor-Acceptor Copolymers with Distinct Supramolecular Organizations
Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level
We compare the charge transport characteristics of heavy doped p- and
n-Si-alkyl chain/Hg junctions. Photoelectron spectroscopy (UPS, IPES and XPS)
results for the molecule-Si band alignment at equilibrium show the Fermi level
to LUMO energy difference to be much smaller than the corresponding Fermi level
to HOMO one. This result supports the conclusion we reach, based on negative
differential resistance in an analogous semiconductor-inorganic insulator/metal
junction, that for both p- and n-type junctions the energy difference between
the Fermi level and LUMO, i.e., electron tunneling, controls charge transport.
The Fermi level-LUMO energy difference, experimentally determined by IPES,
agrees with the non-resonant tunneling barrier height deduced from the
exponential length-attenuation of the current
Electrochemically Exfoliated Graphene as Solution-Processable, Highly Conductive Electrodes for Organic Electronics
Soft X-ray induced oxidation on acrylic acid grafted luminescent silicon quantum dots in ultrahigh vacuum
Water soluble acrylic acid grafted luminescent silicon quantum dots (Si-QDs) were prepared by a simplified method. The resulting Si-QDs dissolved in water and showed stable strong luminescence with peaks at 436 and 604?nm. X-ray photoelectron spectroscopy (XPS) was employed to examine the surface electronic states after the synthesis. The co-existence of the Si2p and C1s core levels infers that the acrylic acid has been successfully grafted on the surface of silicon quantum dots. To fit the Si2p spectrum, four components were needed at 99.45, 100.28, 102.21 and 103.24?eV. The first component at 99.45?eV (I) was assigned to Si–Si within the silicon core of the Si-QDs. The second component at 100.28?eV (II) was from Si–C. The third at 102.21?eV (III) was a sub-oxide state and the fourth at 103.24?eV (IV) was from SiO2 at Si-QDs surface. With an increase in exposure to soft X-ray photons, the intensity ratio of the two peaks within the Si2p region A and B increased from 0.5 to 1.4 while the peak A intensity decreased, and eventually a steady state was reached. This observation is explained in terms of photon-induced oxidation taking place within the surface dangling bonds. As the PL profile for Si-QDs is influenced by the degree of oxidation within the nanocrystal structure, the inducement of oxidation by soft X-rays will play a role in the range of potential applications where such materials could be used – especially within biomedical labelling
Nanostructured ultra thin films by covalent molecular assembly in supercritical carbon dioxide
Ph.DDOCTOR OF PHILOSOPH
Covalent molecular assembly in a supercritical medium: Formation of nanoparticles encapsulated in immobilized dendrimers
10.1021/ie060822qIndustrial and Engineering Chemistry Research462464-471IECR
Covalent molecular assembly in supercritical carbon dioxide: A comparative study between amine- And anhydride-derivatized surfaces
10.1021/la052505eLangmuir2294092-4099LANG
Covalent molecular assembly of multilayer dendrimer ultrathin films in supercritical medium
10.1016/j.jcis.2006.09.051Journal of Colloid and Interface Science3061118-127JCIS
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