Rod and Crossbone P3HT Aggregates in P3HT‐Perylene‐Diimide Solar Cells

We present efficiency and lifetime results for solar cells composed of blends of poly(3‐hexylthiophene‐2,5‐diyl) and N,N′ ‐bis(3‐pentyl)perylene‐3,4,9,10‐bis(dicarboximide) or P3HT:PDI. This combination represents a baseline system for future studies of PDIs as electron acceptors. Poor performance in the fabricated devices was correlated with unusual sample morphologies. Large aggregates in the form of rods and crossbones were observed using both optical and electron microscopy. Energy dispersive X‐ray elemental analysis was used to identify the composition of the structures. These results illustrate the critical connection between polymer organization and solar cell efficiency, providing insights into the structure‐function interaction between PDI and P3HT.