title: Effects of lanthanum ion modifications on the photoelectrochemical properties of ZnO nanorods-based dye-sensitized solar cells.
abstract: We investigated the photoelectrochemical effects on La ion-modified ZnO nanorods for dye-sensitized solar cells (DSSCs), preparing four kinds of samples grown in solutions with 0, 1, 2, and 3 at% of La precursors. It was found that La ion modifications lead to an increase in the lattice constant of ZnO nanorods, resulting in widening of their energy bandgap. I-V results tell that the photoelectrochemical properties increase in the order of 2, 1, 0, and 3 at% La ion-modified ZnO nanorod-based DSSCs. To further analyze and explain the experimental results, we measured absorbance, IPCE, and EIS and concluded that the DSSCs fabricated by using 3 at% La ion-modified ZnO nanorods exhibit better device performances such as Voc, Jsc, and efficiency, suggesting that the amount of La ions is a key parameter of La modified-DSSCs. The results can be explained by Burstein-Mott effects, vertical growth, and La oxide coating effects of the ZnO nanorods.
authors.affiliation: Department of Physics, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Seok Cheol
authors.initials: SC
authors.lastname: Choi
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Yun
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Sohn