Facile Synthesis of Ultrafine Nanoparticles of Iron Based Oxides and Their Application in Solar Cells

Facile and eco-friendly methods have been developed for the fabrication of ultrafine nanoparticles of iron based oxides. Initially, mesoporous α-Fe₂O₃ nanoparticles were prepared by the green tea mediated hydrothermal method. The nanoparticles of α-Fe₂O₃ were highly pure and well crystallized with an average particle size of 60 nm. For the fabrication of ultrafine nanoparticles, the as-prepared  α-Fe₂O₃ were dispersed in propanol and sonicated for 1.5 h. TEM analysis confirmed the formation of single-crystalline nanoparticles with a mean size of 15 nm. The ultrafine nanoparticles showed improved performance when applied in a solar cell. We also prepared Gd and Ti doped BiFeO₃ microparticles by solid state reaction technique, which was then subjected to ultrasonication for the fabrication of ultrafine nanoparticles. The average particles size of the sample was found to be 12 nm. The ultrafine nanoparticles and their bulk counterparts were successfully applied to a solar cell.