Light Harvesting with Dendrimers and Polymers

The search for artificial light-harvesters has lead to the intense study of conjugated dendritic molecules and polymers. The ability to synthesize large macromolecules with defined architectures allows a comprehensive investigation of electronic coupling, exciton formation, and energy transfer. In this work we discuss the nature of electronic excitations and the mechanisms directing the excitation energy to a trap. We will present ultrafast time-resolved experiments in dendritic phenylene ethynylene molecules and poly phenylene ethynelene polyelectrolytes. The dendritic molecules experiments reveal the presence of two localized states in the dendrimer backbone. From both states, the excitation energy is transferred to the energy trap in less than 2 ps, making this molecule one of the fastest light harvesters. To understand the conjugated polyelectrolytes we will present a model involving exciton migration through the polymer chain.

For more information contact Dr. Jean-Luc Brédas (404-385-4985).