Hierarchical TiO2 spheres architectures for quasi solid state dye-sensitized solar cells by living radical polymerization and sol-gel process

摘要

Titanium dioxide (TiO2) photoelectrode is one of the most important components in a dye-sentisized solar cell (DSSC). In common, the overall performance of the DSSC depends on the surface area of the TiO2 photoelectrode which is directly correlated to the amount of dye loading. Dye loading increased with the increase in the surface area of TiO2 layer that enhanced short circuit current (Jsc) performance in DSSC. In addition, for better penetration of electrolytes, it is essential to use the mesoporous or macroporous TiO2 photoelectrode structure than microporous TiO2 photoelectrode structure. The photoelectrode made up of from commercially available TiO2 (P25, Degussa) has limitations mainly because of lower surface area which motivated us to modify it by atom transfer radical polymerization (ATRP) process with hydrophilic poly(ethylene glycol) methyl ether methacrylate (POEM). Dye-sensitized solar cells (DSSCs) made from TiO2 spheres with hierarchical pores exhibited improved photovoltaic efficiency (3.30% for low molecular weight (Mw) and 2.50% for high Mw polymer electrolytes), as compared to those from pristine TiO2 nanoparticles (2.40% for low Mw and 1.30 % for high Mw) at 100 mW/cm², due to the increased surface areas and light scattering.