UNIMOLECULAR RECTIFICATION IN HEXADECYLQUINOLINIUM TRICYANOQUINODIMETHANIDE

摘要

Hexadecylquinolinium tricyanoquinodimethanide is a rectifier of electrical current not only as a Z-type Langmuir-Blodgett (LB) multilayer, but also as a single monolayer (25 A thick). This was measured by two methods: (1) by monitoring the scanning tunneling spectroscopy current across a monolayer on graphite, (2) by measuring the current-voltage curves for a single monolayer sandwiched between an Al metal base electrode and Al pads 1 to 4 mm~2 in area (0.33 electrons / molecule / second). The key to success was in cryocooling the Al base | monolayer in an evaporator as the second Al layer was deposited atop the organic layer. This same molecule was first studied by Ash well for second harmonic generation from Z-type LB multilayers, and by Sambles for its asymmetric current-voltage characteristics (rectification) as a multilayer between dissimilar metal electrodes.