Polyfluorene Bearing Quinoline and Ferrocene as the Pendant Groups for Bioelectronics

Abstract

Abstract Analog-type polymer memristors are preeminent candidates for neuromorphic computation and synaptic biomimicking. A novel polyfluorene bearing quinoline and ferrocene as the pendant groups (PQF) is synthesized. The PQF film sandwiched between the Al and ITO electrodes exhibits outstanding analog-type memristive performance at a small sweep voltage range of ±1V, with 42 distinguishable conductance states. As compared, poly{[9,9-di(2,4-diphenylquinoline)-fluorene]-alt-[9,9-bis(6-bromohexyl)-9H-fluorene]}, and poly {[9H-fluorene]-alt-[fluorene with triazole and ferrocene moieties in the sidechains] only show 12 and 15 distinguishable conductance states, respectively. The former only involves intramolecular charge transfer from the polymer backbone to the quinolone moieties, while the latter mainly concern redox effect from the ferrocene moieties. These results demonstrate that the combined action of intramolecular electron transfer and redox effect could dramatically increase the number of distinguishable conductive states of the resultant materials. Associated with the exceptional memristive performance, the PQF-based memristor can accurately recognize human emotions. After 150 training sessions, the accuracy of emotion recognition reaches up to 98.74%.