Thermal effect on polymer solar cells with active layer concentrations of 3–5 wt%

This studies the thermal effects on a polymer solar cell, consisting of conjugated poly(3-hexylthiophene) (P3HT) and fullerence derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) composites with high concentrations of 3–5 wt%. Improved light absorption, crystalline degree and molecular distribution of highly concentrated of P3HT:PCBM blended films are achieved after the thermal treatment. Additionally, the photocurrent density and power conversion efficiency (PCE) of the present polymer solar cells with 5 wt% P3HT:PCBM film are enhanced by more than sixfolds and sevenfolds, respectively. The 130 °C-treated polymer solar cell with 4 wt% P3HT:PCBM film has a superior PCE of 3.6% under AM1.5 illumination at 100 mW/cm2 due to an enhanced separation efficiency of excitons and balanced carrier mobility.