Ternary Blend Hybrid Solar Cells Incorporating Wide and Narrow Bandgap Polymers

Ternary hybrid solar cells based on zinc oxide with wide bandgap poly(3-hexylthiophene) (P3HT) and narrow bandgap poly[2,3-bis(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (PTQ1) exhibit improved photovoltaic performance compared to that of individual binary hybrid solar cells. The increase in the photocurrent is partly due to the complementary absorption bands, which can extend the light-harvesting range from visible to near-infrared regions, and partly due to efficient energy transfer from P3HT to PTQ1, by which P3HT excitons are more efficiently collected at the PTQ1/ZnO interface and hence convert to charge carriers effectively. Furthermore, the improvement in the fill factor may be due to efficient hole transfer from PTQ1 to P3HT with higher hole mobility, and thereby, hole polarons are more efficiently collected on the electrode.