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Design and Synthesis of p‐n Conversion Indium‐Oxide‐Based Gas Sensor with High Sensitivity to NO x at Room‐Temperature
Author(s) -
Xu Laidi,
Zhang Xinci,
Wang Cheng,
Guo Dechao,
Zhou Linan,
Pang Qingjiang,
Zhang Guo,
Wang Shuhong
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702662
Subject(s) - indium , x ray photoelectron spectroscopy , conductivity , materials science , analytical chemistry (journal) , oxide , adsorption , scanning electron microscope , electrical resistivity and conductivity , transmission electron microscopy , selectivity , infrared spectroscopy , chemical engineering , nanotechnology , chemistry , optoelectronics , composite material , biochemistry , electrical engineering , chromatography , engineering , metallurgy , catalysis , organic chemistry
Indium oxide (In 2 O 3 ) nanoparticles with internal porous structure were obtained through thermal treatment of the hydrothermally synthesized indium hydroxide (In(OH) 3 ) nanocubes precursor. The structure and morphology of In 2 O 3 were characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM). The fresh In 2 O 3 exhibits p ‐type conductivity according to gas response testing. However, the fresh In 2 O 3 allowed switchable p ‐ to n ‐ conductivity after it was induced by high concentration NO x and the induced In 2 O 3 sensor (IIS) exhibited excellent sensing performances in terms of high response, enhanced selectivity and good stability to NO x at room temperature. From the characterization of XPS, it was found that a large amount of oxygen adsorbed on the surface of indium oxide, which led to the n‐p type surface conductivity conversion of In 2 O 3 . The formation of adsorbed species of high concentration NO x induced In 2 O 3 transition from p‐ to n ‐ type surface conduction was investigated by in situ Diffuse Reflectance Infrared Transform Spectroscopy (DRIFT). The present work not only offers a strategy to change the type of electrical conductivity of the material, but also offers an opportunity to deeply understand the mechanism of n ‐ p‐n type electrical surface conductivity conversion.