Materials, Interface, and Device Engineering Towards Low-Cost, Efficient, and Stable Polymer Solar Cells

摘要

An integrated approach combining new materials development, interfacial modifications, device structure optimization and electrode engineering have been adapted to develop low-cost, efficient and stable polymer solar cells. We will first review our recent development of using inverted polymer solar cells with modified ITO (with self-assembled monolayer (SAM)-functionalized ZnO or TiO2) as efficient electron-collecting cathode and PEDOT:PSS/metal as the hole-collecting anode. The modification of the junction between metal oxide and bulk- heterojunction layer with a fullerene-based SAM improves the chemical compatibility and exciton dissociation efficiency at the interface, resulting in significantly increased power conversion efficiency of close to 5%. Furthermore, this new inverted device architecture enables the use of more stable materials as top electrode (PEDOT:PSS/Ag), which significantly improves device stability. Under ambient testing conditions, the flexible and un-encapsulated devices can retain over 85% of their initial efficiency after 40 days shelf-time while the devices made with the conventional configuration showed negligible photovoltaic activity after only 4 days.