文档库

最新最全的文档下载
当前位置:文档库 > Electrodeposition_preparation_of_ZnO_nanobelt_array_films_and_application_to_dye-sensitized_solar_ce

Electrodeposition_preparation_of_ZnO_nanobelt_array_films_and_application_to_dye-sensitized_solar_ce

Journal of Alloys and Compounds462(2008)

Electrodeposition_preparation_of_ZnO_nanobelt_array_films_and_application_to_dye-sensitized_solar_ce

175–180

Electrodeposition preparation of ZnO nanobelt array

?lms and application to dye-sensitized solar cells

Chunfu Lin,Hong Lin?,Jianbao Li,Xin Li

State Key Laboratory of New Ceramics&Fine Processing,Department of Materials Science&Engineering,

Tsinghua University,Beijing100084,People’s Republic of China

Received27March2007;received in revised form21July2007;accepted27July2007

Available online3August2007

Abstract

ZnO nanobelt array?lms were prepared using an electrodeposition method with liquid crystal template.The as-prepared sample was amorphous and changed to nanocrystalline ZnO after sintered at500?C for1h.The sintered?lm with nanobelt width of about5nm was?rst applied as a photoanode of a dye-sensitized solar cell(DSC),and a high short-circuit photocurrent density of17mA/cm2and an overall light-to-energy conversion ef?ciency of2.6%were achieved.

?2007Elsevier B.V.All rights reserved.

Keywords:Electrode materials;Nanostructured materials;Liquid crystals;Nanofabrications

1.Introduction

ZnO has been one of the most promising oxide semicon-ductor materials because of its good optical,electrical,and piezoelectric properties.It can be used in many areas,such as?eld-emission displays,gas sensors,and solar cells.Quasi-one-dimensional nanostructure arrays of ZnO,such as nanowire arrays,nanorod arrays,nanobelt arrays,and nanotube arrays are attracting much interest for their properties and potential applications in nanotechnology.Numerous studies on the prepa-rations of ZnO nanowire arrays,ZnO nanorod arrays and ZnO nanotube arrays have been reported.By contrast,very little work has been focused on ZnO nanobelt arrays.Recently,Yang[1]and Wen[2]have reported the preparation of ZnO nanobelt arrays by a gas–solid reaction process.However,this method needs com-plicated process,and it is still a challenge to synthesize highly ordered ZnO nanobelt arrays with simple process.

Dye-sensitized solar cells(DSCs)have gained much inter-est since reported by O’Regan and Gratzel in1991[3].Low production costs and high ef?ciency for energy conversion make DSC become a promising alternative for the conven-tional photovoltaic devices.Generally,a DSC consists of three

?Corresponding author.Tel.:+861062772848;fax:+861062772672.

E-mail address:lcf@http://www.wendangku.net/doc/94868dd628ea81c758f57800.html(H.Lin).main components:a dye-adsorbed porous nanocrystalline pho-

toanode(e.g.TiO2or ZnO)?lm on a transparent conductive

oxide(TCO)-coated glass substrate(collection electrode),an

iodide/triiodide(I?/I3?)redox couple electrolyte,and a pla-

tinized,TCO-coated glass as counter electrode.Electrons of the

dye are excited by solar energy absorption,and then injected

rapidly from the excited state of the dye into the conduction

band of the photoanode and diffuse to the TCO electrode.Oxi-

dized dye molecules are reduced by I?in the iodide-based liquid

electrolyte by the reaction:3I??I3?+2e?and I?changes to I3?by losing two electrons.At the counter electrode,the reverse

reaction takes place.

For an ef?cient DSC,the photoanode must provide both

large surface area for adsorbing much dye and ef?cient electron

transport for delivering the photo-induced electrons to the col-

lection electrode without recombination.Electron transport in

nanoparticle-based photoanode?lm is proposed to occur either

by a series of hopping events between trap states on neigh-

boring particles[4]or by diffusive transport within extended

states slowed down by trapping/detrapping events[5].Regard-

less of speci?c mechanism,an electron may have to cross an

estimated103–106particles to reach the collection electrode

[4].To decrease the resistance of electron transport,one choice

is to decrease the thickness of nanoparticle photoanode?lm.

However,the surface area will also decrease with the decrease

of the thickness.A good choice is to replace the nanoparticles

0925-8388/$–see front matter?2007Elsevier B.V.All rights reserved. doi:10.1016/j.jallcom.2007.07.104

Electrodeposition_preparation_of_ZnO_nanobelt_array_films_and_application_to_dye-sensitized_solar_ce

TOP相关主题