title: Electrospray preparation of hierarchically-structured mesoporous TiO₂ spheres for use in highly efficient dye-sensitized solar cells.
abstract: We report a simple method to prepare hierarchically structured TiO(2) spheres (HS-TiO(2)), using an electrostatic spray technique, that are utilized for photoelectrodes of highly efficient dye-sensitized solar cells (DSSCs). This method has an advantage to remove the synthesis steps in conventional sol-gel method to form nano-sized spheres of TiO(2) nanoclusters. The fine dispersion of commercially available nanocrystalline TiO(2) particles (P25, Degussa) in EtOH without surfactants and additives is electro-sprayed directly onto a fluorine-dopoed tin-oxide (FTO) substrate for DSSC photoelectrodes. The DSSCs of HS-TiO(2) photoelectrodes show high energy conversion efficiency over 10% under illumination of light at 100 mW cm(-2), AM1.5 global. It is concluded from frequency-dependent measurements that the faster electron diffusion coefficient and longer lifetime of HS-TiO(2) than those in nonstructured TiO(2) contribute to the enhanced efficiency in DSSCs.
authors.affiliation: Optoelectronic Materials Lab., Korea Institute of Science and Technology, Seoul 136-791, Korea.
authors.forename: Daesub
authors.initials: D
authors.lastname: Hwang
authors.forename: Horim
authors.initials: H
authors.lastname: Lee
authors.forename: Sung-Yeon
authors.initials: SY
authors.lastname: Jang
authors.forename: Seong Mu
authors.initials: SM
authors.lastname: Jo
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
authors.forename: Yongsok
authors.initials: Y
authors.lastname: Seo
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Kim