MXene/bentonite thin film for highly sensitive humidity sensor

Humidity sensors are integral to modern technology and extensively utilize Ti₃C₂T_x MXene for its superior sensitivity and accuracy. This material’s effectiveness stems from its abundant hydrophilic functional groups and high electrical conductivity. In this study, we enhanced the responsiveness to relative humidity changes by incorporating bentonite, a 2D clay mineral material and is known for its robust water adsorption capacity and ionic conductivity, attributable to its distinctive structure. Our analysis of MXene/bentonite thin films through sheet resistance measurements indicated a clear inverse relationship in resistance changes above and below a specific MXene-to-bentonite ratio. Impedance analysis further revealed that the dominant conduction mechanisms within these films vary according to the mixing ratio. In fabricating conductive-type humidity sensors from MXene/bentonite films, we observed a remarkable increase in humidity sensitivity. Particularly, MXene rich film (33 wt%) than for the MXene) demonstrated a sensitivity approximately 58.1 times greater than MXene film, and bentonite rich film (MXene ratio 10 wt% MXene) demonstrated about 5,000 times greater than MXene film. This study not only underscores the potential of MXene/bentonite composites in humidity sensing but also highlights the critical role of composition in optimizing sensor performance.

Conference

• Hiroya Morotomi¹,Yuki Matsunaga²,Lijun Liu³,Hisashi Sugime⁴,Jun Hirotani¹, Kyoto University¹,Nagoya University²,Osaka University³,Kindai University⁴, A Highly Sensitive Flexible Humidity Sensor Based on Ti₃C₂T_x MXene/Bentonite Thin Film, 2024 MRS Fall Meeting & Exhibit (Boston, MA), Dec. 1-6, 2024, EL03.10.02