Abstract
In this thesis a new method to arrange dye molecules (porphyrins and perylenes) in a well-organised fashion over extended lengths up to hundreds of nanometers is presented. This method was inspired by the naturally occurring light harvesting systems that are capable of efficient energy transfer over large distances (>100Å), involving tens or hundreds of bacteriochlorophyll pigments. It was envisioned that the arrangement of the dye molecules in a well-defined organisation would require a rigid polymeric scaffold. Polyisocyanides are helical, intrinsically rigid polymers that could serve this purpose. It was recently discovered by our group that polyisocyanides prepared from isocyanodipeptides form stable -helical architectures due to the presence of hydrogen bonding arrays along the helical polymer backbone. This hydrogen bonding network rigidifies the helix and prevents unwinding to a random-coil structure. Besides, the handedness of the polymeric backbone can be tuned by using the appropriate L- or D-amino acids. Using this strategy we have been able to construct a new series of polyisocyanides covered with porphyrins and perylenes, leading to rigid rod polymers with unique optical properties. The polymers have lengths up to several hundred nanometers containing thousands of chromophores in a precisely defined organisation and are capable of excitation energy transfer over several nanometers. These polymers are potentially interesting for application in plastic solar cells.
