Fast exciton diffusion in chiral stacks of conjugated p-phenylene vinylene oligomers

The ultrafast dynamics of photoexcitations were studied in chiral stacks of conjugated p-phenylene vinylene mols. functionalized with hydrogen-bonding groups. In soln., p-p interactions between the mols. give rise to fast exciton diffusion along the stacking axis of the assemblies. The chiral nature of the assemblies is found to cause a rotation of the dipole moment of excitons propagating along the stacks as indicated by time-resolved measurements of the photoluminescence polarization anisotropy. The obsd. exciton diffusion and energy relaxation dynamics in the mol. stacks are similar to those found in conjugated polymer films. Moreover, through changes in the temp. of the surrounding solvent, the stacks can be dissocd. reversibly as shown by a marked redn. in the diffusivity of excitons. [on SciFinder (R)]