Controlled unidirectional energy transfer in luminescent self-assembled conjugated polymer superlattices

We report the synthesis and characterization of multi-layered organic super lattices made by polyelectrolyte self-assembly. Self-assembled films were f ormed from a water-soluble form of poly(phenylene vinylene) with high-photo luminescence quantum efficiency (QE). We observed a self-quenching of the l uminescence with increasing film thickness. This quenching can be reversed by inserting spacer layers between each active conjugated layer. A red shif t of the luminescence was also observed as additional poly(phenylene vinyle ne) layers were added. We attribute the red shift and increasing QE to chan ging polymer conformation, together with efficient unidirectional energy tr ansfer. We rule out quantum confinement as the origin of the red shift. (C) 1999 Elsevier Science B.V. All rights reserved.