Aero-sol–gel synthesis and photovoltaic properties of mesoporous TiO2 nanoparticles

Highly mesoporous TiO2 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 TiO2–NaCl composite nanoparticles, we examined the formation of mesoporous TiO2 nanoparticles with optimized surface area and pore volume distributions. Then, the photovoltaic properties of the resulting mesoporous TiO2 nanoparticles were systematically investigated by forming a photovoltaic active layer of these nanoparticles on the photoanode of dye-sensitized solar cells (DSSCs). The mesoporous TiO2 nanoparticle-based DSSCs fabricated in this study showed an improved short circuit current densities and power conversion efficiencies compared to solid TiO2 nanoparticle-based DSSCs (the values increased from 2.02 ± 0.11 to 8.16 ± 0.51 mA/cm2 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 TiO2 nanoparticles with a specific surface area of 184 m2/g and an average pore size of 5 nm. These specially designed mesoporous TiO2 nanoparticles have great potential as an effective dye-supporting and electron-transfer medium and can help improve the photovoltaic performance of DSSCs.

► Solid and mesoporous TiO2 nanoparticles (NPs) are formed via aero-sol–gel process.
► Porosity of TiO2 NPs is varied by the fraction of inorganic templates.
► Mesoporous TiO2 NPs support higher concentration of dye molecules than solid TiO2.
► Mesoporous TiO2 NPs improve photovoltaic properties in dye-sensitized solar cells.