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Innovative Approach to Photo-Chemiresistive Sensing Technology: Surface-Fluorinated SnO<inf>2</inf>for VOC Detection
ISSN
19448244
Date Issued
2020-08-19
Author(s)
Bahuguna, Gaurav
Mondal, Indrajit
Verma, Mohit
Kumar, Manish
Bhattacharya, Saswata
Gupta, Ritu
Kulkarni, Giridhar U.
DOI
10.1021/acsami.0c08847
Abstract
Transparent electronics continues to revolutionize the way we perceive futuristic devices to be. In this work, we propose a technologically advanced volatile organic compound (VOC) sensor in the form of a thin-film transparent display fabricated using fluorinated SnO2 films. A solution-processed method for surface fluorination of SnO2 films using Selectfluor as a fluorinating agent has been developed. The doped fluorine was optimized to be <1%, resulting in a significant increase in conductivity and reduction in persistent photoconductivity accompanied by a faster decay of the photogenerated charge carriers. A combination of these modified properties, together with the intrinsic sensing ability of SnO2, was exploited in designing a transparent display sensor for ppm-level detection of VOCs at an operating temperature of merely 150 °C. Even a transparent metal mesh heater is integrated with the sensor for ease of operation, portability, and less power usage. A sensor reset method is developed while shortening the UV exposure time, enabling complete sensor recovery at low operating temperatures. The sensor is tested toward a variety of polar and nonpolar VOCs (amines, alcohols, carbonyls, alkanes, halo-Alkanes, and esters), and it exhibits an easily differentiable response with sensitivity in line with the electron-donating tendency of the functional group present. This work opens up the door for multiplexed sensor arrays with the ability to detect and analyze multiple VOCs with specificity.