Distinguishing Intramolecular Electron Transport and Memristivity of π-d- and π-Conjugated Metallopolymers

In contrast to π-conjugated polymers, π-d-conjugated polymers should have distinct electron transport and storage owing to mixed π* orbitals of the organic ligand and the valence d-orbitals of a metal center. However, distinguishing their intrinsic electronic properties in the solid state is an experimental challenge because it lacks a feasible experimental strategy. Here, we present distinguishing intramolecular electron transport and memristivity of π-d- and π-conjugated metallopolymers based on solid-phase electrosynthesis. Unlike general self-assembled assembly, which becomes disordered when the molecular length increases due to the steric hindrance effect, our crystalline monolayers composed of vertical metallopolymers have thicknesses similar to those of theoretical molecular lengths. Thus, distinguishing the intrinsic differences of π-d- and π-conjugated metallopolymers in their electronic properties becomes experimentally feasible. In contrast to π-conjugated metallopolymer monolayers, the UV–vis absorption peak of the π-d-conjugated metallopolymer monolayer has a redshift of 168 nm, the redox peak decreases in 30 mV, the decay constant is surprisingly down from 0.25 ± 0.042 nm–1 to 0.15 ± 0.056 nm–1, and the lower peak bias in 0.13 V for the negative differential resistance response. Our work demonstrates that the π-d-conjugated metallopolymer is superior to the π-conjugated metallopolymer analogue in electron transport, function tuning, and power efficiency of memristive devices.