Ambipolar transport in an electrochemically gated single-molecule field-effect transistor.
Charge transport is studied in single-molecule junctions formed with a 1,7-pyrrolidine-substituted 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) molecular block using an electrochemical gate. Compared to an unsubstituted-PTCDI block, spectroscopic and electrochemical measurements indicate a reduction in the highest occupied (HOMO)-lowest unoccupied (LUMO) molecular orbital energy gap associated with the electron donor character of the substituents. The small HOMO-LUMO energy gap allows for switching between electron- and hole-dominated charge transports as a function of gate voltage, thus demonstrating a single-molecule ambipolar field-effect transistor. Both the unsubstituted and substituted molecules display similar n-type behaviors, indicating that they share the same n-type conduction mechanism. However, the substituted-PTCDI block shows a peak in the source-drain current vs gate voltage characteristics for the p-type transport, which is attributed to a two-step incoherent transport via the HOMO of the molecule.
Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
Ismael
I
Díez-Pérez
Zhihai
Z
Li
Shaoyin
S
Guo
Christopher
C
Madden
Helin
H
Huang
Yanke
Y
Che
Xiaomei
X
Yang
Ling
L
Zang
Nongjian
N
Tao
D004563:Electrochemistry / Q000295:instrumentation; D004579:Electron Transport; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014173:Transistors, Electronic