Res. Chem. Intermed.
, Vol. 34, No. 4, pp. 393–402 (2008)
Koninklijke Brill NV, Leiden, 2008.
Also available online - www.brill.nl/rci
Soft solution synthesis of a zinc oxide nano-screw
superstructure and its composite with nitrogen-doped
, KEN IHARA, RUIXING LI and TSUGIO SATO
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira,
Aoba-ku, Sendai, Japan
Received 25 April 22007; accepted 31 August 2007
Abstract—Novel zinc oxide thin ﬁlms with nano-screw superstructure were prepared via asoft
solution route without any polymer additives. A ZnO thin ﬁlm could be produced directly on
the substrates. The ZnO thin ﬁlm with nano-screw superstructure was prepared using visible-
light-induced nitrogen-doped titania nano-particles. The ZnO nano-screw/TiO
showed excellent photocatalytic deNO
ability and quantum efﬁcient.
Keywords: Soft solution process; ZnO nano-screw; nitrogen-doped titania; photocatalyst.
ZnO is an exceptionally important material which possesses many unique optical
and electrical properties for applications in wide research ﬁelds such as photocata-
lyst, solar cell, sensor, pigments, UV shielding material, etc. Recently, as one of the
wide band-gap semiconductors, ZnO is of great interest for applications in short-
wavelength ultraviolet lasers [1, 2] and blue light-emitting diodes (LEDs) [3, 4].
Controlled growth of nanocrystallines has attracted wide interest in material re-
search because of their unique and novel optical, electric, chemical and catalytic
properties . Up to now, well-deﬁned ZnO nanostructures with unique morpholo-
gies, such as nanorings , nanocombs, nanosprings [7, 8], nanopropellers, tetrapod
 and tetraleg structures , have been reported. Most of them were prepared by
a solid-state thermal sublimation process. It is generally accepted that the formation
of zinc oxide superstructures in liquid media is more difﬁcult than that by solid-state
thermal sublimation process, because the crystalline growth in solution is mainly re-
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