Rational design of semiconducting polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(6-{4-ethyl-piperazin-1-yl}-2-phenyl-benzo{de}isoquinoline-1,3-dione)] for highly selective photoelectrochemical assay of p- phenylenediamine

Herein, this paper reports a simple and label-free photoelectrochemical (PEC) sensor based on the organic semiconducting conjugated polymer-polyfluorene derivative, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(6-{4-ethyl-piperazin-1-yl}-2-phenyl-benzo{de}isoquinoline-1,3-dione)] (PFNA). The PFNA was designed and obtained the lowest unoccupied molecular orbital (LUMO)/highest occupied molecular orbital (HOMO) values via spectral characterizations. The PFNA modified electrode produced a stable and enhanced photocurrent sig-nal under white light irradiation at a bias of -0.1 V in phosphate buffer solution. A sensitive increment of the photocurrent was observed with the addition of p-phenylenediamine (p-PD). A possible mechanism for this photoelectrochemical process including the photoexcitation of the polymer, electron injection from polymer toward the electrode, and the hole-scavenging process by the reductants were studied. The pi bond in the poly-mer might facilitate the photoelectrochemical process owing to the enhanced electronic coupling between the polymer and the reductants. A PEC analysis on p-PD has been carried out to evaluate the photoelectrochemical performances of the modified electrode, which presents the wide linear ranges of 0.2-400 mu M, with a lower detection limit of 0.13 mu M. This work reports the PEC performance of organic semiconducting conjugated poly-mer-polyfluorene derivative, which would promote more efficient photoelectrochemical design of sensors and devices.

Automated summary

This paper presents a simple and label-free photoelectrochemical sensor based on an organic semiconducting conjugated polymer called polyfluorene derivative. The modified electrode demonstrated a stable and enhanced photocurrent signal when exposed to white light. The addition of p-phenylenediamine resulted in a sensitive increase in photocurrent. The findings suggest that the π bond in the polymer enhances the photoelectrochemical process and shows potential for efficient design of sensors and devices.