Hybrid polymer solar cells with well ordered TiO 2 nanostructures have attracted attention as a promising new photovoltaic device. This new device structure is to improve the power conversion efficiency of a solar cell by enhancing light absorption, charge injection, and carrier transport. In this study, sol-gel and atomic layer deposition (ALD) methods were used for the fabrication of various TiO 2-based nanostructures of hybrid polymer solar cells. Morphological properties of those fabricated individual nanostructures and solar cell device structures were analyzed by high resolution TEM and 3D tomography techniques. Our result shows that sol-gel method produces crystallized TiO 2 nanostructures with a property of efficient electron transport and nanogroove structure has better infiltration of polymer materials into the inorganic region than nanocylinder structure.