A Self‐Powered Gas Sensor Based on Coupling Triboelectric Screening and Impedance Matching Effects

Abstract Triboelectric gas sensors enable the detection of the target gas through measuring the variation of triboelectric output signal without an external power supply. The output depends greatly on triboelectric surface alteration of certain chemisorption of gas species. However, the impact of the variation in impedance of sensor electrodes altered by external stimuli is usually neglected, which can significantly affect the output signal of the sensor. In this work, a coupling triboelectric screening and impedance matching effects‐based high‐performance self‐powered triboelectric gas sensor has been proposed. Polyaniline (PANI) film is employed as both electrodes and positive triboelectric layer, as well as sliced polytetrafluoroethylene spaced on PANI as negative triboelectric layer. When exposed to ammonia, the output voltage decreases with the increasing concentration, and the response in low ammonia concentrations exhibits a steep slope, on account of limited active adsorption sites on triboelectric layers. The surface potential distributions of PANI film in three different gaseous ambient measured by in situ Kelvin probe force microscopy and experimental analysis systematically elaborate the triboelectric screening effect. Finally, a sensing‐electrode theoretical model has been demonstrated to verify the impedance matching effect of PANI electrode, opening up an effective strategy for the new generation of triboelectric sensors.