Nanostructured Nanorod Arrays Presenting TiO₂ Nanorods/Poly(3-hexylthiophene) for Solar Cells Application

We have fabricated inverted heterojunction solar cell devices incorporating titanium dioxide nanorod/poly(3-hexylthiophene) (P3HT) rod arrays using melt-assisted anodic alumina oxide template. Using transmission electron microscopy and conductance atomic force microscopy, we revealed that phase-separated TiO₂ rich (n-type) and P3HT rich (p-type) regions presents in these rod arrays. The optimized composite rod array structure had a higher hole mobility than that of the blend film consisting of TiO₂ nanorod and P3HT 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 nanorod arrays provided it with both a higher short-circuit current density and power conversion efficiency.