Phase Engineering of SnSe_X (X = 1,2) Microstructures for High-Performance NO₂ Chemiresistive Room-Temperature Sensor...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Two-dimensional (2D) materials like tin selenide (SnSeX) are promising for gas sensors.
• The exact gas sensing mechanisms of SnSe and SnSe2 are not fully understood.
• Phase engineering is a key strategy to enhance SnSeX properties.

Purpose of the Study:

• To investigate the phase engineering of SnSeX using a hydrothermal route.
• To correlate phase transformation with NO2 gas detection properties.
• To understand the underlying mechanisms for enhanced gas sensing.

Main Methods:

• Hydrothermal synthesis of SnSeX using 1-dodecanethiol (1-DDT) as a phase stabilizer.
• Systematic variation of 1-DDT concentration to control SnSeX phase.
• Gas sensing measurements of SnSeX at varying 1-DDT concentrations.
• Computational calculations to elucidate gas adsorption mechanisms.

Main Results:

• Increasing 1-DDT concentration transformed SnSe to SnSe2.
• NO2 gas response increased from 45% to 1430% with SnSe2 formation.
• SnSe2 sensors showed excellent NO2 discrimination and stability in humid conditions.
• Computational results indicated enhanced NO2 adsorption on SnSe2 with Se vacancies.

Conclusions:

• Phase engineering of SnSeX via hydrothermal synthesis with 1-DDT is effective for NO2 sensing.
• SnSe2 demonstrates superior NO2 sensing performance compared to SnSe.
• The study provides insights into the mechanism of enhanced gas sensing in SnSe2.
• A SnSe2-based sensor module was developed for real-time NO2 monitoring.