title: Solution-derived 40 microm vertically aligned ZnO nanowire arrays as photoelectrodes in dye-sensitized solar cells.
abstract: Well-aligned ZnO nanowire arrays with a long length of more than 40 microm were prepared successfully by using the polyethylenimine (PEI)-assisted preheating hydrothermal method (PAPHT). Several important synthetic parameters such as PEI content, growth time, preheating time and zinc salt concentration were found to determine the growth of ultralong ZnO nanowire arrays, including length, diameter, density and alignment degree. The photoluminescence (PL) spectrum of as-grown ultralong ZnO nanowire arrays revealed a UV emission and a yellow emission, which was attributed to the absorbed hydroxyl group based on the peak shift after annealing in various atmospheres. The performance of dye-sensitized solar cells (DSSCs) increased with increasing length of ZnO nanowire arrays, which was mainly ascribed to the aggrandized photocurrent and reduced recombination loss according to electrochemical impedance spectroscopy (EIS). A maximum efficiency of 1.3% for a cell with a short-circuit current density (J(sc)) = 4.26 mA cm(2), open-circuit voltage (V(oc)) = 0.69 V and (fill factor) FF = 0.42 was achieved with a length of 40 microm.
authors.affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China. jj qiu@163.com
authors.forename: Jijun
authors.initials: J
authors.lastname: Qiu
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.forename: Fuwei
authors.initials: F
authors.lastname: Zhuge
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Gan
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Gao
authors.forename: Weizhen
authors.initials: W
authors.lastname: He
authors.forename: Se-Jeong
authors.initials: SJ
authors.lastname: Park
authors.forename: Hyung-Kook
authors.initials: HK
authors.lastname: Kim
authors.forename: Yoon-Hwae
authors.initials: YH
authors.lastname: Hwang