"The channel part requires semiconducting materials whose resistance can be sensitively controlled by external bias," explained Jang-Ung Park, Assistant Professor at Ulsan National Institute of Science and Technology (UNIST), in an interview for Phys.org. "The electrode part needs metallic materials whose resistance is very small with the negligible change by external bias."
The Korean researchers, representing both the UNIST and the Korea Electrotechnology Research Institute, have demonstrated that the fully integrated, all-carbon devices can be attached to a wide variety of surfaces including plants, insects, paper, clothes and human skin. The flexible electronic sensors remain attached to the surfaces by exploiting van der Waal forces, which represent all the attractive or repulsive forces between molecules that are not covalent bonds.
The researchers took the unusual step of applying the flexible sensors to plants and insects to see if the devices could be used to detect very low levels of DMMP vapor (1 ppm), which is used for producing nerve agents such as soma and sarin. Park told Nanoclast that his team's devices performed comparably to current state-of-the-art sensors and showed that the sensors could be used to monitor a variety of environmental conditions, including temperature, humidity, pollution and infections. The devices do not need a battery because the researchers have integrated an antenna onto the devices that can be used to receive power.