Preparation of hierarchical TiO2 films with uniformly or gradually changed pore size for use as photoelectrodes in dye-sensitized solar cells

- Polystyrene (PS) microspheres were used to fabricate films with different pore sizes.
- Flims with different pore sizes were obtained by burning out varying amount of PS.
- The photoelectrode with appropriate pore size had optimum performance.
- A hierarchical TiO2 photoelectrode with pore size gradually increasing was prepared.
- The hierarchical TiO2 photoelectrode had best photoelectric conversion efficiency.