Photonic Crystal Geometry for Organic Polymer:Fullerene Standard and Inverted Solar Cells

We describe a 2-D photonic crystal (PC) geometry that enhances the absorption of light for organic photovoltaic (OPV) cells relative to conventional planar cells. The PC geometry is developed by patterning an organic photoactive bulk heterojunction blend of P3HT (poly(3-hexylthiophene)) and PCBM (phenyl-C61-butyric acid methyl ester) via PRINT (pattern replication in nonwetting templates), a method that lends itself to large area fabrication of nanoscale features. Replication flexibility for various patterns and ranges of materials emphasizes the utility of PRINT for both inverted and standard OPV architectures. The optical properties of PC cells for different device architectures are investigated theoretically and experimentally in order to determine critical physical dimensions that influence device performance.