Solution-processed bilayer photovoltaic devices with nematic liquid crystals

Abstract

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices.

Keywords:

• liquid crystals
• photovoltaics
• bilayer
• cross-linking
• reactive mesogen
• perylene
• bulk heterojunction

Acknowledgements

G. Sowersby is thanked for technical support. We acknowledge the EPSRC for financial support.