A sensing device tailored for mass production of highly sensitive and stable nerve-gas detectors has been developed by a research group led by Dr. Li Shi, assistant professor of mechanical engineering at the University of Texas at Austin. The research demonstrated the sensor’s potential ability to detect a single molecule of the nerve gas sarin, the most toxic of biological warfare agents.

The researchers designed and tested a nanometer-thin crystal of tin oxide sandwiched between two electrodes. When a built-in micro-heater heated the super-thin device, the tin oxide reacted with exquisite sensitivity to gases. Shi’s group experimented with a non-toxic gas, dimethly methylphosphonate (DMMP), widely used to accurately mimic sarin and other nerve agents. The sensor element responded to as few as 50 molecules of the DMMP in a billion air molecules.

Both the nano-sizing of the metal-oxide and the unique micro-heater element of the sensor gave the detector its high sensitivity, stability, and low power consumption. The thinner a metal-oxide sensor becomes, the more sensitive it becomes to molecules that react with it. In addition to improved sensitivity, the group found its single-crystal metal-oxide nanomaterials allowed the detector to quickly dispose of previously detected toxins and accurately warn of new toxins’ presence.

The sensor requires a high temperature to activate the reaction between DMMP molecules and the tin-oxide sensor element. That reaction changes the electrical current across the crystal, which indicates a nerve agent is present.

Find out more at: www.engr.utexas.edu