Multi-modal, ultrasensitive, wide-range humidity sensing with Ti3C2 film

Abstract

Gravimetric, direct-current electrical, and electrical impedance sensing modes were used to measure response of high surface area 2D Ti₃C₂ MXene film to water vapor pressures spanning 3 orders of magnitude (20 mTorr–20 Torr). The Ti₃C₂ film exhibited reproducible reversible response in 0.1%–95% relative humidity (RH) range with a detection limit of <20 mTorr H₂O partial pressure (<0.1% RH). DC electrical current-based sensing with 3 mV operating voltage and 0.8 pW power consumption was demonstrated. The highest normalized sensitivity was shown for gravimetric sensing modalities which scale with the overtone number, reaching highest sensitivity of about 12 Hz/% RH at the 9^th crystal overtone (45 MHz oscillation).