Electronic Devices that Can Smell

In recent years, generative AI related to text, images, and music has become increasingly familiar in our daily lives. One of the reasons for the development of these generative AIs is the existence of vast amounts of digital data for AI to learn from. This digital data can be collected using advanced visual and auditory sensors such as cameras and microphones.

So, what about olfactory sensors? While oxygen concentration meters and gas leak detectors are common in homes and workplaces, there is no all-purpose, easy-to-use odor sensor that can identify the concentration of each of the many molecules present in our environment. If we could digitize diverse gas concentrations all at once, we could create unprecedentedly useful applications in combination with AI. For example, one possibility is to replace the superior sense of smell of dogs. A dog's sense of smell is utilized in a wide range of fields, including the detection of hazardous materials and illegal drugs, as well as cancer detection in living organisms. However, because this relies on living animals, it requires significant cost and time for training, and it is not possible to integrate multiple functions (such as hazardous material detection and healthcare functions). On the other hand, olfactory sensors based on electronic devices can be integrated and mass-produced, which are characteristic features of electronic devices. It is expected that this will allow tests that could previously only be conducted in specialized facilities to be brought into the home.

The Tanaka Laboratory, established in 2023, is conducting research on integrable gas sensors using microfabrication technology. From the perspective of conventional electronic devices, exposure to the outside air causes unwanted chemical reactions and leads to performance degradation. For this reason, transistors, which form the basis of various integrated circuits, have been encapsulated to prevent exposure to the outside air. We, on the other hand, are challenging this by actively exposing electronic devices to the outside air and attempting to sense gases from the resulting changes in electrical properties. Therefore, we are enjoying our research as we work to elucidate unknown phenomena in the interdisciplinary field of chemistry and electronics, focusing on the properties of electronic devices that depend on surface chemical reactions.