Electrical Rectification by a Mnnolayer of Hexadecylquinolinium Tricyanoquinodimethanide Sandwiched between Gold Electrodes

摘要

Unimolecular rectification, previously reported between oxide-bearing electrodes, was detected between oxide-free Au electrodes for a Langmuir-Blodgett monolayer of the zwitterionic D~+-π-A~- molecule hexadecylquinolinium tricyanoquinodimethanide, C_(16)H_(33)Q-3CNQ. The top gold electrode was deposited from a Au vapor pre-cooled by multiple collisions with Ar atoms. The maximum rectification ratio is 27.5 at 2.2 Volts (the average rectification ratio is 7.55). The currents are as large as 9.04 X 10~4 electrons molecule~(-1) s~(-1). The result reinforces previous work with oxide-bearing Al electrodes, but the currents with Au electrodes are larger by three to five orders of magnitude.