Efficient electron collection in hybrid polymer solar cells: In-situ-generated ZnO/poly(3-hexylthiophene) scaffolded by a TiO₂ nanorod array

A nanoarchitectural hybrid polymer solar cell, integrating the ordered and the bulk heterojunction hybrid polymer solar cells, is fabricated by infiltrating the diethylzinc/poly(3-hexylthiophene) (P3HT) solution into the interstices of the TiO₂ nanorod (NR) array. An inorganic network composed of tiny ZnO nanocrystals is constructed in the in-situ-generated hybrid within the interstice of the single-crystalline TiO₂ NRs. The TiO₂ NR array, which possesses a longer electron lifetime and an appropriate electron-transport rate, serves not only as an electron transporter/collector extended from fluorine-doped tin oxide (FTO) electrode to sustain the efficient electron collection but also as a scaffold to hold the sufficient amount of ZnO/P3HT hybrid. The in-situ-generated ZnO/P3HT hybrid layer with superior charge separation efficiency can therefore be thickened in the presence of a TiO₂ NR array for increasing the light-harvesting efficiency. A notable efficiency of 2.46% is therefore attained in the TiO ₂ NR-ZnO/P3HT hybrid solar cell.