Aero-sol-gel synthesis and photovoltaic properties of mesoporous TiO ₂ nanoparticles

Highly mesoporous TiO ₂ nanoparticles were synthesized by using a combination of aero-sol-gel and aqueous washing processes. By varying the mass fraction of NaCl templates in the TiO ₂-NaCl composite nanoparticles, we examined the formation of mesoporous TiO ₂ nanoparticles with optimized surface area and pore volume distributions. Then, the photovoltaic properties of the resulting mesoporous TiO ₂ nanoparticles were systematically investigated by forming a photovoltaic active layer of these nanoparticles on the photoanode of dye-sensitized solar cells (DSSCs). The mesoporous TiO ₂ nanoparticle-based DSSCs fabricated in this study showed an improved short circuit current densities and power conversion efficiencies compared to solid TiO ₂ nanoparticle-based DSSCs (the values increased from 2.02±0.11 to 8.16±0.51mA/cm ² and from 1.07±0.21% to 3.88±0.33%, respectively). This improvement is due to an increase in the amount of inorganic dye (N719) adsorption in the mesoporous TiO ₂ nanoparticles with a specific surface area of 184m ²/g and an average pore size of 5nm. These specially designed mesoporous TiO ₂ nanoparticles have great potential as an effective dye-supporting and electron-transfer medium and can help improve the photovoltaic performance of DSSCs.