Investigation on Excited-State Photophysical Characteristics of Low Bandgap Polymer APFO3 (cited: 1)

The excited state photophysics of low bandgap polymer APFO3 has been investigated in detail. The chemical calculations confirm that the intrachain charge transfer (ICT) may occur after photo-excitation and is mainly responsible for the first absorption band. The transient absorption results confirm that ICT indeed exists and competes with the vibra-tional relaxation at the same time, when APFO3 is in a monodisperse system. This ICT process would disappear due to the influence of interchain interaction when APFO3 is in the condensed phase, where the exciton decay would be dominant in the relaxation process after photoexcitation. The photoexcitation dynamics of APFO3 film blending with PC₆₁BM are presented, which shows that the exciton may be dissociated completely as the percentage of PC₆₁BM reaches ～50%. Meanwhile, the photovoltaic performance based on blend het-erojunction shows that the increase of photocurrent is little if the percentage of PC₆₁BM exceeds ～50%. Overall, the present study has covered several fundamental processes taking place in the APFO3 polymer.