Hybrid templated synthesis of crack-free, organized mesoporous TiO ₂ electrodes for high efficiency solid-state dye-sensitized solar cells

Organic/inorganic hybrid templates, i.e., aluminium oxide (Al ₂O₃) nanoparticles grafted with poly(oxyethylene) methacrylate, Al₂O₃-POEM, are synthesized via surface-initiated atom transfer radical polymerization (ATRP), as confirmed by Fourier transform-infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Upon combining the Al₂O₃-POEM with titanium(IV) isopropoxide (TTIP), hydrophilic TTIP is selectively confined in the hydrophilic POEM chains through hydrogen bonding interactions. Following the calcination at 450 °C and the selective etching of Al₂O₃ with NaOH, the OM-TiO₂ films with high surface areas, good interconnectivity, and anatase phase are obtained. The solid-state dye-sensitized solar cells (ssDSSCs) fabricated with OM-TiO₂ photoelectrodes and a polymerized ionic liquid (PIL) show a high energy conversion efficiency of 7.3% at 100 mW cm^-2, which is one of the highest values for ssDSSCs. The high cell performance is due to the well-organized structure, resulting in improved dye loading, excellent pore filling of electrolyte, enhanced light harvesting, and reduced charge recombination.