Poly(3-hexylthiophene):Fullerene Photovoltaic Cells compatibilized by Rod-Coil Block Copolymers Under Different Annealing Conditions

A recipe for making the best-performing morphology in poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester (P3HT:PC71BM) bulk heterojunction (BHJ) solar cells was proposed applying thermal and solvent annealings in the presence of P3HT-based rod-coil block copolymers consisting of hydrophilic and hydrophobic coily blocks, i.e., poly(styrene) (PS), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (PEG). Unlike the uncompatibilized photovoltaic cells, the power conversion efficiency (PCE) dropping during both thermal and solvent annealings was prevented for all BHJ devices compatibilized with either hydrophobic- or hydrophilic-based block copolymers. The observed behavior was assigned to ever increasing trend of the fill factor (FF) as well as increasing or marginally decreasing trend of the short circuit current density (Jsc). The Jsc and PCE peaked at 12.10 mA/cm2 and 4.85%, respectively, within 1 h under solvent annealing by 20 wt% of P3HT7150-b-PS compatibilizers.

Keywords:

P3HT-PC71BM-BHJ-annealing