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Synthesis of zinc oxide crystals with different shapes from zincate aqueous solutions stabilized with triethanolamine
Author(s) -
Ban Takayuki,
Sakai Tomoyuki,
Ohya Yutaka
Publication year - 2007
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.200710960
Subject(s) - zincate , triethanolamine , zinc , aqueous solution , materials science , chemical engineering , substrate (aquarium) , agglomerate , inorganic chemistry , chemistry , analytical chemistry (journal) , composite material , organic chemistry , metallurgy , oceanography , engineering , geology
ZnO crystals were synthesized from basic aqueous solutions including zincate ions stabilized with triethanolamine (N(C 2 H 4 OH) 3 , teaH 3 ) by heating at 60°C. The influence of the basicity of the solutions on the morphology of the ZnO crystals was examined. The aqueous solutions were prepared using ZnSO 4 ·7H 2 O, N(CH 3 ) 4 OH (TMAOH), and teaH 3 as a zinc source, a base, and a stabilizer, respectively, at a zinc concentration of 0.2 M at a teaH 3 / Zn molar ratio of 4. Clear solutions were obtained at a molar ratio of TMAOH / Zn ≥ 3.0. When the clear solutions, in which glass or polyester substrates were placed, were heated at 60°C, agglomerates of ZnO crystals were deposited on the substrates in the TMAOH / Zn range from 3.0 to 3.6. With increasing the TMAOH / Zn ratio, the shape of the resulting ZnO crystals changed from a short asymmetric column with a hexagonal flat edge and a rounded one, through a rocket‐like shape formed by intergrowth, to a hexagonal rod. Although no films of ZnO were formed, ZnO crystals with different shapes were synthesized. When the glass substrates pre‐coated with a ZnO thin film by a sol‐gel method were used, highly oriented, dense ZnO films were formed. The films consisted of rod‐like crystals aligned normal to the substrate surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)