Electronic Trap-State Modulation in Sm-Doped SnO₂ Nanofibers Enables Ultrasensitive Hydrogen Sensing.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Growing demand for sub-parts per million (ppm) hydrogen (H₂) sensing in environmental monitoring, disease diagnostics, and battery safety.
• Challenges in achieving reliable ppb-level H₂ detection using traditional chemiresistive metal oxide sensors, especially without noble metal catalysts.

Purpose of the Study:

• To develop a novel, highly sensitive, and noble-metal-free chemiresistive sensor for trace hydrogen detection.
• To investigate the mechanism of enhanced H₂ sensing in samarium-doped tin dioxide nanofibers.

Main Methods:

• Fabrication of samarium-doped tin dioxide (Sm-SnO₂) nanofibers.
• Characterization of H₂ sensing performance at 200 °C.
• Utilized X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) for mechanistic studies.

Main Results:

• Achieved clear detection of H₂ down to 25 ppb with a theoretical limit of detection of 4.5 ppb.
• Demonstrated significantly enhanced H₂ sensitivity in 2 at% Sm-doped SnO₂ nanofibers compared to undoped counterparts.
• Identified that Sm³⁺ doping introduces deep trap states, enhancing H₂ response through trap-assisted charge release.

Conclusions:

• Trap-state engineering via rare-earth doping (Sm-SnO₂) is an effective strategy for ultrasensitive, noble-metal-free hydrogen sensing.
• The developed Sm-SnO₂ nanofibers show promise for applications requiring ppb-level H₂ detection.
• This approach offers a pathway to overcome limitations of conventional metal oxide sensors for trace gas detection.