Synthesis of Mesoporous Titanium Dioxide Nanoparticles and Their Application into Dye Sensitized Solar Cells

다국어 초록 (Multilingual Abstract)

In order to improve the overall power conversion efficiency in dye-sensitized solar cells (DSSCs), it is very important to secure the sufficient surface area of photocatalytic nanoparticles layer for absorbing dye molecules. It is because increasing the amount of dye absorbed generally results in increasing the amount of light harvesting. In this work, we proposed a new method for increasing the specific surface area of photocatalytic titanium oxide (TiO₂) nanoparticles by using an inorganic templating method. Salt-TiO₂ composite nanoparticles were synthesized in this approach by spray pyrolyzing both the titanium butoxide and sodium chloride solution. After aqueous removal of salt from salt-TiO₂ composite nanoparticles, mesoporous TiO₂ nanoparticles with pore size of 2~50 nm were formed and then the specific surface area of resulting porous TiO₂ nanoparticle was measured by Brunauer-Emmett-Teller (BET) method. Generally, commercially available P-25 with the average primary size of ~25 nm TiO₂ nanoparticles was used as an active layer for dye-sensitized solarcells, and the specific surface area of P-25 was found to be ~50 m²/g. On the other hand, the specific surface area of mesoporous TiO₂ nanoparticles prepared in this approach was found to be ~286 m²/g, which is 5 times higher than that of P-25. The increased specific surface area of TiO₂ nanoparticles will absorb relatively more dye molecules, which can increase the short curcuit current (Jsc) in DSSCs. The influence of nanoporous structures of TiO₂ on the performance of DSSCs will be discussed in terms of the amount of dye molecules absorbed, the fill factor, the short circuit current, and the power conversion efficiency.