Nanorod-nanosheet hierarchically structured ZnO crystals on zinc foil as flexible photoanodes for dye-sensitized solar cells.
In this paper, ZnO nanorod-nanosheet hierarchical structures were fabricated using a facile method on zinc foil and used as flexible photoanodes in dye-sensitized solar cells (DSCs). Compared to nanorods (NRs) obtained by the dissolution-precipitation method, the nanorod-nanosheet (NR-NS) hierarchical structures obtained by a second-step homogeneous precipitation improved the performance of DSCs by increasing photocurrent density significantly. As a result, the power conversion efficiency of the devices based on such a NR-NS hierarchical structure reached up to 2.4% under 100 mW cm(-2) illumination condition. This represents an enhancement by 108% as compared to DSCs based on NR assembled nanoflowers, for which the efficiency was 1.1%. The enhancement of the photocurrent was due mainly to the much larger specific surface area and resulting dye-loading amount. The electron transport properties in this structure were also investigated by means of electrochemical impedance spectroscopy (EIS). Furthermore, the formation mechanism of the NR-NS hierarchical structures are discussed.
Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA.
Rui
R
Gao
Jianjun
J
Tian
Zhiqiang
Z
Liang
Qifeng
Q
Zhang
Liduo
L
Wang
Guozhong
G
Cao
D004396:Coloring Agents / Q000737:chemistry; D058266:Dielectric Spectroscopy; D011211:Electric Power Supplies; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D012993:Solar Energy; D013696:Temperature; D015034:Zinc Oxide / Q000737:chemistry*
D004396:Coloring Agents; D004573:Electrolytes; D015034:Zinc Oxide