Hierarchical TiO 2 nanostructured array/P3HT hybrid solar cells with interfacial modification

In this work, ordered hybrid polymer solar cells have been fabricated using rutile TiO ₂ nanoarchitecture arrays, i.e., nanorod (NR) and nanodendrite (ND) arrays, and poly(3-hexylthiophene) (P3HT). The performance of the rutile TiO ₂ NR/P3HT hybrid solar cell is significantly improved through interface modification with Z907 or D149 dye molecules. The enhancement of open-circuit voltage is attained in the dye-modified hybrid solar cell, which may be attributed to the lowering of the work function of the TiO ₂ NR array by dye adsorption. In addition to be the photocurrent contributor, the dye molecule plays a crucial role in the interface morphology of the TiO ₂ NR/P3HT hybrid. Z907 and D149 dye molecules not only provide an appropriate band alignment in between P3HT/TiO ₂ NR but also improve the compatibility of interface morphology of the hybrid. Charge separation and electron lifetime are therefore improved in the dye-modified TiO ₂ NRs/P3HT hybrid solar cells, resulting in the enrichments of the cell performances. Three-dimensional TiO ₂ ND arrays are further employed to enlarge the interface area of the ordered heterojunction hybrid solar cell. Compared to the D149-modified TiO ₂ NR/P3HT hybrid solar cell, considerable enhancement of charge separation is observed in the D149-modified TiO ₂ ND/P3HT solar cell. A notable efficiency of 3.12% is therefore achieved in the D149-modified TiO ₂ ND array/P3HT hybrid solar cell.