Efficient Electron Transfer through Interfacial Water Molecules across Two-Dimensional MoO₃ for Humidity Sensing.

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Resistive humidity sensors are crucial for flexible and integrated electronic devices.
• Two-dimensional molybdenum trioxide (MoO3) possesses a large interface area, allowing for broad modulation of electrical properties.

Purpose of the Study:

• To synthesize two-dimensional MoO3 for humidity-sensing applications.
• To evaluate the humidity-sensing performance of 2D MoO3.
• To investigate the sensing mechanism of MoO3 under varying humidity levels.

Main Methods:

• Synthesis of 2D MoO3 via liquid-phase exfoliation.
• Humidity-sensing tests were conducted.
• Impedance spectra and voltage-current scans were used to analyze the sensing mechanism.

Main Results:

• 2D MoO3 exhibited superior humidity-sensing performance, including high sensitivity (9794 Ω/RH at 25 °C), negligible hysteresis, linearity, and stability.
• The resistance change is attributed to interfacial conductance modulated by water adsorption.
• Hydrogen bonding at the interface facilitates conducting paths and enhances electron transfer.

Conclusions:

• 2D MoO3 is a promising material for advanced electronic humidity sensors.
• The study provides a deeper understanding of electronic humidity sensing mechanisms.
• A novel perspective on electronic humidity sensing is proposed.