Keto-defect induced abnormal exciton behavior in hybrid conjugated polymers

This study investigates energy transfer in fluorescent polymers with defects, particularly focusing on a defect-controlled donor polymer's impact on Förster resonance energy transfer (FRET). Electrospun porous tubes (EPT) containing fluorescent donor and acceptor polymers were developed, introducing defects in the donor polymer. These defects act as singlet charge traps, influencing the fluorescence lifetime of the conjugated backbone The FRET efficiency according to the theory was calculated as the PL quenching of the defect-less donor and the lifetime reduction, but it was confirmed that the defective donor polymer contradicted the theory. Additionally, FRET membranes composed of EPT were utilized in volatile organic compound (VOC) gas sensors. VOCs disrupted FRET by affecting the pores in the tubes, enabling specific VOC identification with a single FRET membrane type. Fluorescence lifetime imaging microscopy (FLIM) was used to observe changes in the dynamics of excitons affected by VOC penetration into EPT. As a result, the defect in the donor polymer increased the fluorescence lifetime according to the quenching of the donor's emission, and this phenomenon can lead to a critical error when applied to the FRET theory.