Measurement of voltage-dependent electronic transport across amine-linked single molecular wire junctions We present a new technique to measure a statistically defined current-voltage curve and apply this method to three molecules4 4’-Diaminostilbene 4,4 -Diaminostilbene, Bis-(4-aminophenyl)acetylene, Bis-(4-aminophenyl)acetylene and 1,61 6diaminohexane. We find that 4,4’-Diaminostilbene exhibits the largest increase in differential conductance as a function of applied bias. This indicates that the predominant transport channel for 4,4’-Diaminostilbene (the highest occupied molecular orbital) is closer to the Fermi level of the metal than that of the other molecules, consistent with the trends observed in the molecular ionization potential.
0 05 0.05
0.00 0.10 Current (µ (µA))
0.00 -0.05
0 05 0.05
0.00 0.10 Current (µ (µA))
0
-200
500
0
1000
200
Measured Voltage (mV)
N
C
VM H
1.6 1.4 1.2 1.0
0.02 0.00
VA
100 200 300 400 VM(mV)
1 2 3
-0.02
-0.10 1500
-0.15 400
H
0
0.00
H
X
0.04
-0.05
-0.10 -0.15
1000
0.10
0
0.06
2000
0.15
Current (µA)
Current (µA)
0.10
B
Counts
0.15
Counts
500
Current ((µA)
0.20
A
N
(dI/dV)/(dI/dV)45mVV
0.20
H
X is: 1) C=C I 2) C≡C
0
-200
1000
0
2000
200
Measured Voltage (mV)
3000
-0.04
400
-200
0
200
Measured Voltage (mV)
400
