Effect of alkoxy side chains on intra and interchain exciton coupling in PPE-PPV copolymers solution

- Five derivatives of PPE-PPVs, with symmetrical and dissymmetrical configurations of alkoxy side chains, in solutions, have been used.
- Photoluminescence (PL) and time-resolved PL measurements have been done.
- Using Franck-Condon (FC) analysis, we showed the impact of the side chain configuration on the formation of H, J or HJ aggregate domains in solutions.
- Symmetrical and total dissymmetrical configurations lead to H and J-aggregate domains, respectively.
- We have shown that the long-lived emission is from H-aggregates while the short-lived emission is from the J-aggregate type.

The effects of alkoxy side chains on the optical and morphological properties of five poly (p-phenylene-ethylene)-alt-poly (p-phenylene-vinylene)s (PPE-PPVs) solutions are investigated. By steady-state and time-resolved photoluminescence spectroscopy combined with Franck-Condon analyses, we show that the introduction of symmetrical side chains onto the PPE-PPV backbone increases the π-π stacking between the polymer chains leading to interchain interactions hence H-aggregate domains. Total dissymmetrical side chains lead to J-aggregate domains through intrachain interactions. On the other hand partial dissymmetrical side chain configurations lead to H and HJ-aggregate domains.