Inverted heterojunction solar cells incorporating fullerene/polythiophene composite core/shell nanorod arrays

We have fabricated inverted heterojunction solar cell devices incorporating [6,6]-phenyl-C61-butyric acid methyl ester/poly(3-hexylthiophene) core/shell nanorod arrays by using an anodic alumina oxide template. The internal quantum efficiencies and external quantum efficiencies of these core/shell nanorod inverted solar cells were higher than those of the corresponding conventional inverted bulk heterojunction device. The optimized nanorod array structure had a high hole mobility that was over one order magnitude greater than that of the conventional bulk heterojunction structure, as determined by fitting the dark J–V curves into the space charge limited current model. The more efficient carrier transport of the device incorporating the core/shell nanorod arrays provided it with both a higher short-circuit current density and power conversion efficiency.