While 5G communications networks along with the Internet of Things (IoT) are becoming part of everyday life, Estonian researchers at the University of Tartu are busy developing a graphene-based sensor nose. This breakthrough allows smartphone users to get immediate notifications about their environment. According to the World Health Organization, outdoor air pollution is one the biggest health risks and a major cause of death and disease globally. This is also an acute problem in Europe: 72% of Europeans live in urban areas and are daily exposed to toxic substances in air.
But there is also good news. In the near future, smart sensors in your phone, a few square millimetres in size, will detect poisonous gases in ambient air, especially vehicle exhaust. Sensors could also be used, for example, in a smart home, while sensors connected to the Internet of Things could relay the situation of a whole city or region. These will give a much more accurate picture of pollution than current individual monitoring stations. ‘In addition, the final sensor platform will feature pressure, magnetic field, temperature and humidity sensors,’ says Raivo Jaaniso, head of the laboratory and a senior research fellow at the University of Tartu.
A local research group has been working on the sensor nose for five years and presented their latest prototype in February at the Barcelona World Mobile Congress in the Graphene Pavilion. The fresh prototype does not look anything like a mobile phone yet; it is quite big and would not fit in a pocket. But it already has a processor, Bluetooth, GPS and touchscreen. ‘We met many people there who really needed it and were a little disappointed that we didn’t have the product ready yet,’ says Jaaniso. But big breakthroughs always need time and the project is halfway complete, with plenty of work and experimenting ahead for the next four years.
Largest project in Europe
The gas-smelling sensor, the working principles of which resemble the human nose, has been developed in the framework of the ten-year technology partnership “Graphene Flagship”, established by the European Commission in 2013. This means that the know-how of 150 partners is combined, including universities and the electronics industry. With a total budget of one billion euros, it is also Europe’s biggest research initiative ever.
‘There are more than ten different work packages and topics in the project and we participate in the sensor work package,’ explains Jaaniso. Various project partners have their special expertise. While one group is developing pressure sensors, the others are trying to find other materials for creating gas sensors. ‘Cooperation is very important and the strength of the project is that we also work with other packages that develop, for example, graphene synthesis,’ says the researcher. On a broader level, the work package contributes to the health, medicine, and sensor divisions of the Flagship.
The project on this scale surely needs enormous coordination, various skills and bright minds at work. ‘In our group, very different competencies are required. At the moment, we do not have a thing ready yet, it is still at the research stage, but it has a relatively high level of technical readiness,’ says Jaaniso. To achieve the needed technical level, the University of Tartu work group draws from all disciplines: material science, chemistry and physics, electronics and IT.
Testing on the streets
The local group’s expertise lies in gas sensors. Their latest prototype already allows researchers to start experimenting with the sensor on the street level and not just in the lab. ‘We can make it weatherproof and put it on the arm, bag or bike and then you get the results from the street. Test results from a real environment are very important because there are probably new things and issues that need to be addressed and solved,’ Jaaniso says.
The graphene nose is a relatively simple matrix of sensors, having four small elements. All of them are made out of a graphene layer one atom thick, but each element is modified differently. While one element is focused on sensing one type of gas pollutant, the other element measures another gas. By combining the signals, researchers get data about the current air quality.
At the moment, there are still three criteria the research team has to meet in order for the invention to be used in mainstream technology. ‘We would like to have our sensors be really sensitive, small in size and with low power consumption. It seems that on the basis of graphene it is possible to make sensors that would also endure,’ Jaaniso says. Luckily, the experiments at the University of Tartu Institute of Physics lab have proven that elements created there three years ago still work.
But how exactly will the sensor work? Jaaniso explains that a smart device with the sensor can alarm individuals and recommend that they take a route through unpolluted city zones, whereas the 5G network and IoT will allow the information to be sent quickly to the main database, thus giving a general overview of the area. All of this should give people more choices and a healthier environment.
