Mesophase Ordering of TiO₂ Film with High Surface Area and Strong Light Harvesting for Dye-Sensitized Solar Cell

Department of Electrical and Computer Engineering, National University of Singapore.

Agency for Science Technology and Research.

Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore.

Mesophase ordering and structuring are carried out to attain optimized pore morphology, high crystallinity, stable porous framework, and crack-free mesoporous titanium dioxide (TiO₂) films. The pore structure (quasi-hexagonal and lamellar) can be controlled via the concentration of copolymer, resulting in two different types of micellar packing. The calcination temperature is also controlled to ensure a well-crystalline and stable porous framework. Finally, the synthesized mesoporous TiO₂ film is modified by adding P25 nanoparticles, which act as scattering centers and function as active binders to prevent formation of microcracks. Adding P25 nanoparticles into mesoporous structure helps to provide strong light-harvesting capability and large surface area for high -efficiency dye-sensitized solar cells (DSSC). The short-circuit photocurrent density (J_sc) of the cell made from mixture of mesoporous TiO₂ and P25 nanoparticles displays a higher efficiency of 6.5% compared to the other homogeneous films. A combination of factors such as increased surface area, introduction of light-scattering particles, and