The Naked-Eye Detection of NH3–HCl by Polyaniline-Infiltrated TiO2 Inverse Opal Photonic Crystals

Authors

  • Cihui Liu,

    1. Jiangsu Key Laboratory of Atmospheric Environment, Monitoring and Pollution Control Nanjing University of Information Science and Technology, Nanjing 210044, P. R. China
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  • Guizhi Gao,

    1. Jiangsu Key Laboratory of Atmospheric Environment, Monitoring and Pollution Control Nanjing University of Information Science and Technology, Nanjing 210044, P. R. China
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  • Yuqi Zhang,

    Corresponding author
    1. Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Fax: (+86) 10-8267 2719
    2. College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, Shaanxi, 716000, P. R. China
    • Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Fax: (+86) 10-8267 2719.
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  • Libin Wang,

    1. Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Fax: (+86) 10-8267 2719
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  • Jingxia Wang,

    1. Jiangsu Key Laboratory of Atmospheric Environment, Monitoring and Pollution Control Nanjing University of Information Science and Technology, Nanjing 210044, P. R. China
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  • Yanlin Song

    Corresponding author
    1. Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Fax: (+86) 10-8267 2719
    • Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, Fax: (+86) 10-8267 2719.
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Abstract

A reversible color change of a polyaniline-infiltrated TiO2 inverse opal photonic crystal (PC) film can be obtained when the PC is switched from an acidic to alkali vapor environment. In a saturated NH3 environment, the stopband of the as-prepared PCs changes from 556 to 688 nm; such large shift of 132 nm could be observed, corresponding to a clear color change from green to red. After placing in HCl vapor, the stopband undergoes a blue-shift and the color turns back to green. The result is ascribed to PANI being doped or dedoped by acid or base and the effective refractive index of the PC film varying accordingly. The naked-eye detection of NH3 and HCl vapors can be realized by the reversible color change of the PC film, which is of importance for chemical and biological sensors.

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