Humidity sensors based on ZnO/TiO2 core/shell nanorod arrays with enhanced sensitivity

SENSORS AND ACTUATORS B-CHEMICAL

卷:159

Article

Gu, Lei¹  Zheng, Kaibo¹  Zhou, Ying²  Li, Juan¹  Mo, Xiaoliang¹  Patzke, Greta R.²  Chen, Guorong¹ 

[1] Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China

[2] Univ Zurich, Inst Inorgan Chem, CH-8057 Zurich, Switzerland

关键词: ZnO/TiO2;    Core/shell materials;    Nanorod arrays;    Capacitance;    Humidity sensors;   

DOI  :  10.1016/j.snb.2010.12.024

来源: Elsevier

【 摘 要 】

Highly aligned arrays of ZnO/TiO2 core/shell nanorods were fabricated on glass substrates by hydrothermal growth of ZnO nanorods cores followed by the deposition of anatase TiO2 shells in a sol-gel process. The characterization of these composite materials with scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and transmission emission microscopy (TEM) points to the formation of crystalline ZnO nanorod cores that are coated with anatase TiO2 shells. Humidity sensors based on these core/shell nanorod arrays exhibit outstanding sensitivities with capacitances varying from 10(1) to 10(6) pF over a relative humidity (RH) range of 11%-95% at room temperature, which is 1.5 and 3 orders of magnitude higher than that of pristine TiO2 films and ZnO nanorods, respectively. Complex impedance analysis indicated that the enhanced humidity sensitivity is probably due to the high surface/volume ratio of this core/shell material in combination with the remarkable hydrophilicity of the TiO2 shell. (C) 2011 Elsevier B.V. All rights reserved.

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