Length and conjugation-controlled memristive functions of metallopolymer monolayers

Abstract

Solid-phase synthesis as a bottom-up strategy may be a superior way to integrate sophisticated functions into an ultrathin film for miniaturized devices. However, the sluggish reaction dynamics at the solid-liquid interface have been a great challenge. Herein, we present four electrochemical reactions for rapidly synthesizing length and conjugation-controlled metallopolymer monolayers. This electrosynthesis requires self-assembled monolayers as templates as a prerequisite to predefine the growth and orientation of the metallopolymers. Electrosynthesis involves a pair of redox reactions: the oxidation self-coupling of pyrene or carbazole, and the reduction self-coupling of the alkyne or vinyl, respectively. They can form conjugation-controlled connections of monomers and provide different lengths of metallopolymers. The resulting metallopolymer monolayers show similar values in thickness and theoretical molecular length, indicating that these metallopolymers stand almost vertically and uniaxially on electrodes with minimum polymer disorder. These crystalline monolayers exhibit both high modulus and conductance while presenting the memristive functions with optical and electrical binary responses as a function of the length and conjugation-controlled metallopolymer monolayers. It is highly anticipated that critical factors including reproducibility, speed, and operational simplicity with the robust design of various molecular junctions will enable rapid automated synthesis of two-dimensional semiconductors for integrated and miniaturized optoelectric devices.