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Single
Molecule
Conductivity in Organic and Biomimetic Molecules
(Guoxiu
Wei, and
Yangjun Xing) |
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The conductance
of single molecules depends not only on how conductive the molecule is but
also on how the molecule connects to the electrodes. Our group has
designed a conjugated thiol linker which can improve the conductance of the
molecule-electrode junction. We continue to explore this topic by
using the STM (scanning tunneling microscopy) break-junction method to study
the conductance of single conjugated molecules with conjugated thiol
linkers.
Conjugated Thiol Linker for Enhanced Conductivity of Gold-Molecule Contacts
(Yufan He)
PNA is an
artificial analog of DNA. PNA has neutral backbone may allow more
compact SAM growth than for DNA. Metal ions can be introduced into PNA
duplexes by replacing the natural bases with metal complexing ligands. We study the
self-assembly and charge transfer of PNA using Scanning Probe Microscopy
(SPM), Cyclic Voltammetry.
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Nanoscale
Dynamics at Liquid/Solid Interfaces
(Yangjun
Xing,
Guoxiu Wei, and
Sean Keuleyan) |
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We use surface charge
to control
adsorbate-substrate interactions and
to
tune dynamics at solid-liquid interfaces. We use Scanning
Tunneling Microscopy
(STM)
and Atomic Force Microscopy
(AFM) to study the
resulting phenomena:
- Molecular redox dynamics at electrode-electrolyte
interfaces.
- Molecular diffusion and self-assembly.
Related Papers
Previous studies:
1. Dynamics of surface reconstruction and lifting of
the
reconstruction, nanoscale islands decay/growth.
Atomic and Molecular STM/AFM at Liquid/Solid Interfaces
(Yufan He, Tao
Ye)
2.
Potential
driven phase transition in aromatic Self-assembled Monolayer (SAM)
(Kyoungja Seo)
3. Read/Write/Erase
nanolithography (Kyoungja Seo)
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Properties of Single-Walled Carbon
Nanotubes and other Carbon Materials
(Nikolay Dementev
and
Dmitry
Kazachkin) |
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*Collaboration with Prof. Radisav Vidic (Environmental Engineering,
Univ. of Pittsburgh).
Understanding the interaction between molecules and carbon nanotubes,
activated carbon fibers and activated carbon is key to a number of
applications. We use FTIR
and TPD under vacuum
conditions. Environmental applications include development of new and
better sorbents for pollution control.
Related Papers
Previous studies:
Environmental Applications of Carbonaceous Surfaces
(Seokjoon Kwon)
*Collaboration with Profs. Karl Johnson (Chemical Engineering) Radisav Vidic
(Environmental Engineering).
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Non-linear
Optical Studies of Interfaces
(Ali Eftekhari,
Oleksandr Isaienko and
Allison
Pymer) |
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Second order
nonlinear optical techniques, e.g,
Sum
Frequency Generation (SFG)
and Second Harmonic Generation (SHG) provide both ultrafast time resolution and
interface selectivity.
Related Papers
Previous studies:
SHG
Spectroscopy & Dynamics of Semiconductor Interfaces
(Dora Bodlaki, Vasiliy Fomenko, Julie Fiore, Catherine Faler)
Nonlinear Optical
Spectroscopy of Electrode-Electrolyte Interfaces (Vasiliy Fomenko)
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Hydrogen Sensors
(Sean
Keuleyan,
Ali Eftekhari
and
Yangjun Xing) |
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In collaboration with ASRD, we are developing
surface acoustic wave sensors for NASA applications.
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Fluorescence Detection of
Surface Functionality
(Nikolay Dementev, and
Yangjun Xing) |
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FLOSS (Fluorescence Labeling
of Surface Species) exploits the sensitivity of fluorescence and the
specificity of covalent bond formation to identify and quantify low
concentrations of surface functionalities. FLOSS can distinguish between
COOH, OH and aldehyde groups and detect down to 1011 functional
groups/cm2 on surfaces. This sensitivity is well beyond the
detection limits of FTIR and XPS.
FLOSS has been applied to understand SAM photoreactivity and is being
extended to other materials.
Principle
of FLOSS
Related Papers
Previous studies:
Growth,
Stability and Photoreactivity of Self Assembled Monlolayers
(Tao, Ye, Eric Mc Arthur) |
