Synthesis of oligo phenylene vinylenes for organic photovoltaic cells

摘要

A series of oligo phenylene vinyles (OPVs) have been prepared using a generic step-wise and uni-directional synthesis from stilbene type monomers containing masked aldehyde and benzylic phosphonate ester functionalities. In the course of this investigation six different monomers with alkyl or alkoxy substituents and with benzene, thiophene or benzothiadiazole groups were developed and prepared. Trimer OPVs were assembled and their optical spectra investigated. Systematic end-group modification gave a series of donor-wire-acceptor OPVs that were used to prepare simple large area photovoltaic cells (3 cm2) without any fullerene derivatives. The efficiency of the devices were measured and compared based on the short circuit current ISC. Two materials were found to perform 10-100 fold better than standard PPV materials and the other OPVs investigated. Another type of end capping with a terpyridine moiety was realized to prepare an example of an OPV-ruthenium dye. A series of devices with mixtures of OPVs with the soluble fullerene derivative PCBM were made and characterized. A maximum efficiency of 0.8 % under AM1.5 conditions were found for a thiophene containing OPV trimer mixed with PCBM (1:4).