A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays

Li-Ko Yeh; Jie-Chun Luo; Min-Chun Chen; Chih-Hung Wu; Jian-Zhang Chen; I-Chun Cheng; Cheng-Che Hsu; Wei-Cheng Tian

doi:10.3390/s16111820

A Photoactivated Gas Detector for Toluene Sensing at Room Temperature Based on New Coral-Like ZnO Nanostructure Arrays

Sensors (Basel). 2016 Oct 31;16(11):1820. doi: 10.3390/s16111820.

Authors

Li-Ko Yeh¹, Jie-Chun Luo², Min-Chun Chen³, Chih-Hung Wu⁴, Jian-Zhang Chen⁵, I-Chun Cheng⁶, Cheng-Che Hsu⁷, Wei-Cheng Tian^{8

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Affiliations

¹ Graduate Institute of Electronics Engineering, National Taiwan University, Taipei City 10617, Taiwan. likoyeh@gmail.com.
² Graduate Institute of Electronics Engineering, National Taiwan University, Taipei City 10617, Taiwan. life2145@hotmail.com.
³ Department of Chemical Engineering, National Taiwan University, Taipei City 10617, Taiwan. b99504035@ntu.edu.tw.
⁴ Graduate Institute of Applied Mechanics, National Taiwan University, Taipei City 10617, Taiwan. ki781219@gmail.com.
⁵ Graduate Institute of Applied Mechanics, National Taiwan University, Taipei City 10617, Taiwan. jchen@ntu.edu.tw.
⁶ Department of Electrical Engineering, National Taiwan University, Taipei City 10617, Taiwan. iccheng@ntu.edu.tw.
⁷ Department of Chemical Engineering, National Taiwan University, Taipei City 10617, Taiwan. chsu@ntu.edu.tw.
⁸ Graduate Institute of Electronics Engineering, National Taiwan University, Taipei City 10617, Taiwan. wctian@ntu.edu.tw.
⁹ Department of Electrical Engineering, National Taiwan University, Taipei City 10617, Taiwan. wctian@ntu.edu.tw.
¹⁰ Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei City 10617, Taiwan. wctian@ntu.edu.tw.

Abstract

A photoactivated gas detector operated at room temperature was microfabricated using a simple hydrothermal method. We report that the photoactivated gas detector can detect toluene using a UV illumination of 2 μW/cm². By ultraviolet (UV) illumination, gas detectors sense toluene at room temperature without heating. A significant enhancement of detector sensitivity is achieved because of the high surface-area-to-volume ratio of the morphology of the coral-like ZnO nanorods arrays (NRAs) and the increased number of photo-induced oxygen ions under UV illumination. The corresponding sensitivity (ΔR/R₀) of the detector based on coral-like ZnO NRAs is enhanced by approximately 1022% compared to that of thin-film detectors. The proposed detector greatly extends the dynamic range of detection of metal-oxide-based detectors for gas sensing applications. We report the first-ever detection of toluene with a novel coral-like NRAs gas detector at room temperature. A sensing mechanism model is also proposed to explain the sensing responses of gas detectors based on coral-like ZnO NRAs.

Keywords: ZnO coral-like nanostructures; ZnO gas detector; photoactivation; room temperature sensing.