Synthesis and photo-induced charge separation of confined conjugation length phenylene vinylene-based polymers†
Abstract
We report the synthesis and photophysics of four confined chromophore phenylene vinylene (PPV)-based polymers where PPV-type trimer chromophores are linked by alkyl ether chains of increasing length (PT3–PT6). These confined chromophore polymers were blended in a 1 : 1 w/w ratio with the fullerene derivative PCBM and the photoinduced charge-separation properties compared to that of a fully conjugated polymer analogue (alt-co-MEH-PPV). Fluorescence from all polymers is quenched in the presence of PCBM and transient absorption measurements confirm the presence of polymer polarons arising from charge transfer from the polymer to the PCBM acceptor. The polaron decay kinetics of all the blend films were similar but the yields of polarons for the confined conjugation length polymers were lower than for alt-co-MEH-PPV:PCBM. These observations suggest that many of the initially formed radical ion pairs for the confined length polymers are unable to fully charge dissociate and undergo fast geminate recombination.
- This article is part of the themed collection: Conjugated polymers