High-efficiency photovoltaic devices based on annealed poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1- phenyl-(6,6)C61 blends

The effects of annealing and fullerene loading in regioregular poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) based bulk heterojunction photovoltaics have been investigated. Under specific loading and annealing conditions, a combination of morphological and electronic factors can be brought to play to achieve optimal filling factors, open-circuit voltage (Voc), and short-circuit current density (Jsc). We demonstrate that this occurs at surprisingly low loadings of PCBM and annealing temperatures nearing the melting point of the polymer. Further, we report power conversion efficiencies approaching 5% in the P3HT:PCBM system.