Molecular Engineering of Tetracene- Fullerene Adducts: Searching for New Electron Acceptor Materials Used in Polymer Photovoltaic Cells

摘要

It is well known that the electronic properties of organic semiconductors are largely determined by their solid state structures. In conjugated polymer-based photovoltaic devices, fullerene derivatives such as [6,6]-phenyl-C61-butyric acid methyl esters (PCBM) are used prevalently as the electron acceptor materials because of their excellent processability, electron affinity and compatibility with donor conjugated polymers. However, the crystal packing of these materials is merely controllable even if the micro- or nanocrystals formed in polymer/PCBM blends are found to be critical to the overall photovoltaic performance. Although the predication and control of the molecular packing in organic solids is difficult and lack of success in general, it is relatively reliable for substituted oligoacences. Therefore in this work we synthesized a series of substituted tetracenes/C_(60) adducts and tested their function as acceptors in polymer photovoltaic devices. It is our goal to develop new fullerene-based n-type materials outperforming PCBM by exploring the structure-property relationship.