Tunnel junction sensing of TATP explosive at the single-molecule level

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Triacetone triperoxide (TATP) is a dangerous homemade explosive frequently used in terrorist activities.
• Current TATP detection methods face challenges due to the compound's volatility and the lack of portable sensing technologies.

Purpose of the Study:

• To propose and theoretically investigate a novel approach for single-molecule TATP detection in ambient air.
• To demonstrate the feasibility of using tunneling current measurements in nanogaps for sensitive explosive detection.

Main Methods:

• Utilizing density functional theory (DFT) combined with the non-equilibrium Green's function (NEGF) method.
• Simulating tunneling current through TATP molecules trapped in nitrogen-terminated carbon nanotube nanogaps.
• Analyzing the electronic structure and charge transport properties of the TATP-nanogap system.

Main Results:

• Calculated a significant tunneling current (tens of nanoamperes) through single TATP molecules in the nanogap.
• Achieved high discrimination ratios (several orders of magnitude) against common volatile organic compounds (VOCs).
• Identified the key role of the TATP highest occupied molecular orbital (HOMO), electrode electric field, and molecular hybridization in facilitating the current.

Conclusions:

• The proposed method offers a promising pathway for highly sensitive and selective single-molecule TATP detection.
• The findings suggest the potential for developing portable and effective explosive detection devices.
• The principle can be extended to other nanogap systems like graphene nanogaps and break-junctions.