Excellent Room-Temperature NO<sub>2</sub> Gas-Sensing Properties of TiO<sub>2</sub>-SnO<sub>2</sub> Composite Thin Films Under Light Activation

Excellent Room-Temperature NO<sub>2</sub> Gas-Sensing Properties of TiO<sub>2</sub>-SnO<sub>2</sub> Composite Thin Films Under Light Activation

Thin TiO<sub>2</sub>–SnO<sub>2</sub> nanocomposite films with high gas sensitivity to NO<sub>2</sub> were synthesized by oxidative pyrolysis and comprehensively studied. The composite structure and quantitative composition of the obtained film nanomaterials have b...

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Bibliographic Details
Main Authors: Victor V. Petrov, Aleksandra P. Starnikova, Maria G. Volkova, Soslan A. Khubezhov, Ilya V. Pankov, Ekaterina M. Bayan
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Nanomaterials
Subjects:
gas sensors
light activation
metal oxide
composites
thin films
TiO<sub>2</sub>
Online Access:https://www.mdpi.com/2079-4991/15/11/871
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Summary:Thin TiO<sub>2</sub>–SnO<sub>2</sub> nanocomposite films with high gas sensitivity to NO<sub>2</sub> were synthesized by oxidative pyrolysis and comprehensively studied. The composite structure and quantitative composition of the obtained film nanomaterials have been confirmed by X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy, which causes the presence of n-n heterojunctions and provides improved gas-sensitive properties. The sensor based on the 3TiO<sub>2</sub>–97SnO<sub>2</sub> film has the maximum responses, which is explained by the existence of a strong surface electric field formed by large surface potentials in the region of TiO<sub>2</sub>–SnO<sub>2</sub> heterojunctions detected by the Kelvin probe force microscopy method. Exposure to low-intensity radiation (no higher than 0.2 mW/cm<sup>2</sup>, radiation wavelength—400 nm) leads to a 30% increase in the sensor response relative to 7.7 ppm NO<sub>2</sub> at an operating temperature of 200 °C and a humidity of 60% RH. At room temperature (20 °C), under humidity conditions, the response is 1.8 when exposed to 0.2 ppm NO<sub>2</sub> and 85 when exposed to 7.7 ppm. The lower sensitivity limit is 0.2 ppm NO<sub>2</sub>. The temporal stability of the proposed sensors has been experimentally confirmed.
ISSN:2079-4991

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