Molecular Switches

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Molecular Switches
Insert molecular switches in defects in
monolayers. Measure isolated molecules and
bundles. Recent measurements of several thousand
molecules indicate that they can be switched with
an applied electric field. Can a single molecule
switch? What is the switching mechanism?
Conjugated molecule synthesized by Jim Tour, Rice
U.
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Molecular Switches

• How many molecules are required for switching? 1.

Molecular Switches
Vsample 1.4 VI 0.2 pA3 min/frame
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Molecular Switches

• What is switching mechanism? Conformational
  changes.
• Switching rate depends strongly on local matrix
  density and order.

4-(2-Nitro-4-phenylethynyl-phenylethynyl)-benzenet
hiolate (2)
Donhauser et al., Science (2001), in press
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Molecular Switches

• Insert fully conjugated molecules with built-in
  dipole into self-assembled films of alkanethiols.
• How many molecules are required for switching? 1.
• What is mechanism of switching? Conformational
  changes.

Molecules synthesized by Jim Tour Group, Rice
U. Nanopore measurements by Mark Reed Group,
Yale U.
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Molecular Rulers for Scaling Down Nanostructures
Gap is controlled by molecular rulers chosen.
Hatzor Weiss, Science 291, 1019 (2001)
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Molecular Rulers for Scaling Down Nanostructures
Art Jamie Perruquet Daily Collegian

• Hatzor PSW, Science 291, 1019 (2001)

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Molecular Ruler for Scaling Down
NanostructuresFormation of Precisely Defined
Electrode Spacings
17 nm
60 nm
Metal wire 17 nm wide between the parent
electrodesfrom initial gap of 60 nm (with 20 nm
ruler spacing) FE SEM Image