Surface Functionalized Sensors for Humidity‐Independent Gas Detection. Issue 12 (16th February 2021)

• Record Type: Journal Article
• Authors: Qu, Fengdong; Zhang, Shendan; Huang, Chaozhu; Guo, Xuyun; Zhu, Ye; Thomas, Tiju; Guo, Haichuan; Attfield, J. Paul; Yang, Minghui
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 12(2021)
• Page Start: 6561
• Page End: 6566
• Publication Date: 2021-02-16
• Subjects: hydrophobicity -- metal–organic frameworks -- metal oxides -- nanoparticles -- semiconductors -- sensors; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202015856
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Semiconducting metal oxides (SMOXs) are used widely for gas sensors. However, the effect of ambient humidity on the baseline and sensitivity of the chemiresistors is still a largely unsolved problem, reducing sensor accuracy and causing complications for sensor calibrations. Presented here is a general strategy to overcome water‐sensitivity issues by coating SMOXs with a hydrophobic polymer separated by a metal–organic framework (MOF) layer that preserves the SMOX surface and serves a gas‐selective function. Sensor devices using these nanoparticles display near‐constant responses even when humidity is varied across a wide range [0–90 % relative humidity (RH)]. Furthermore, the sensor delivers notable performance below 20 % RH whereas other water‐resistance strategies typically fail. Selectivity enhancement and humidity‐independent sensitivity are concomitantly achieved using this approach. The reported tandem coating strategy is expected to be relevant for a wide range of SMOXs, leading to a new generation of gas sensors with excellent humidity‐resistant performance. Abstract : A surface functionalization strategy, utilizing Co‐MOF/PDMS as tandem coating layers, was proposed to overcome the problem of humidity sensitivity for semiconducting metal‐oxide‐based gas sensors. This approach can be extended to various humidity‐independent gas‐sensing materials.