Room-temperature ultrasensitive methanol detection in HfO2 gasistor with Joule heating-assisted recovery.

A memristor-based gas sensor (gasistor) with an Ag/HfO2/ITO structure was developed for highly selective methanol detection at room temperature. In the high-resistance state (HRS), the device exhibits nearly 100-fold higher response than conventional chemiresistive sensors and ultrafast response (<1 s). It also shows over threefold selectivity toward methanol in ethanol-rich environments, highlighting excellent anti-interference capability. Density functional theory (DFT) analysis indicates strong interactions between methanol molecules and the HfO2 surface in the HRS, explaining the high response and slow recovery. To accelerate desorption, a linear DC sweep was applied to induce localized Joule heating, enabling rapid gas release, as confirmed by ab initio molecular dynamics (AIMD) and theoretical calculations.