title: "Secondary Growth" in Hydrothermal Synthesis of Aligned ZnO Nanostructures and Its Application in Dye-Sensitized Solar Cells.
abstract: One-dimensional (1D) aligned ZnO nanostructures were prepared on ZnO film seeded substrates using a low-temperature hydrothermal method, and zinc nitrate and hexamethylenetetramine (HMT) precursors. It was observed that increasing the concentration ratio of Zn2+/HMT from 1 to 100 led to a "secondary growth," and a change in the morphologies of the ZnO nanostructures from arrays of thick nanorods to arrays of thin nanorod-step-thick nanorods. The morphological evolution of ZnO nanostructures with increased growth time at high Zn2+/HMT concentration ratios showed the same transformation. Dye-sensitized solar cells (DSSCs) were fabricated using ZnO nanostructures as the photoanodes, and the electron transport properties were determined by electrochemical impedance spectroscopy (EIS). Although the DSSCs showed low power conversion efficiencies due to the short lengths, the arrays of the thin nanorods demonstrated excellent electron transport with an electron diffusion coefficient (Dn) of 1.57 x 10(-3) cm2/s, and an effective diffusion length (L) of 140 µm.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Huang
authors.forename: Tengji
authors.initials: T
authors.lastname: Huang
authors.forename: Peijiang
authors.initials: P
authors.lastname: Cao
authors.forename: Shun
authors.initials: S
authors.lastname: Han
authors.forename: Fang
authors.initials: F
authors.lastname: Jia
authors.forename: Deliang
authors.initials: D
authors.lastname: Zhu
authors.forename: Xiaocui
authors.initials: X
authors.lastname: Ma
authors.forename: Youming
authors.initials: Y
authors.lastname: Lul