Photophysical properties and energy transfer mechanism of PFO/Fluorol 7GA hybrid thin films

Abstract

Photophysical properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/2-butyl-6- (butylamino)benzo [de] isoquinoline-1,3-dione (Fluorol 7GA) and energy transfer between them have been investigated. In this work, both PFO and Fluorol 7GA act as donor and acceptor, respectively. Based on the absorption and luminescence measurements, the photophysical and energy transfer properties such as fluorescence quantum yield (Φf), fluorescence lifetime (τ), radiative rate constant (kr), non-radiative rate constant (knr), quenching rate constant (kSV), energy transfer rate constant (kET), energy transfer probability (PDA), energy transfer efficiency (η), critical concentration of acceptor (Co), energy transfer time (τET) and critical distance of energy transfer (Ro) were calculated. Large values of kSV, kET and Ro suggested that Förster-type energy transfer was the dominant mechanism for the energy transfer between the excited donor and ground state acceptor molecules. It was observed that the Förster energy transfer together with the trapping process are crucial for performance improvement in ITO/(PFO/Fluorol7GA)/Al device.