Nanostructuring Approach Toward Highly Sensitive CO₂ Gas Sensor Fabrication

The strain generation and heterostructure formation are two important parameters in 2D thin films that could modulate their carrier generation process. Depending upon the carrier migration dynamics the device’s sensitivity towards different external parameters varies. Specifically, detecting target gas molecules in the parts per billion (ppb) level requires a high signal-to-noise ratio and precise selectivity. The strain-induced structures like nanoscrolls provide unidirectional electronic motion with high mobility.¹ The unique morphology of nanoscroll generates abundant adsorption sites that provide facile permeability of target molecules towards the sensing material.² Our approach is to scroll up 2D materials’ heterostructure utilizing the surface tension difference between the film and the substrate. The resultant scroll structure provides 10 times improved conductivity compared to the film counterpart. Functionalizing the scrolls with specific molecular probes enhances the selectivity of the structure toward carbon dioxide (CO₂) gas molecules.³ Our result exhibits that structural modification is a simple approach to achieve highly sensitive molecular detection in a mixed gas environment which is crucial in monitoring toxic gas molecules in the atmosphere.

References:

1. Ghosh, R. et. al., QD/2D Hybrid Nanoscrolls: A New Class of Materials for High-Performance Polarized Photodetection and Ultralow Threshold Laser Action. Small 2020, 16, 2003944.

2. Ghosh, R. et. al., Enhancing the Photoelectrochemical Hydrogen Evolution Reaction through Nanoscrolling of Two-Dimensional Material Heterojunctions. ACS Nano 2022 16 (4), 5743-5751.

3. Cui, S. et al. Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors. Nat Commun 6, 8632 (2015).