Russian scientists have developed a multi-sensor chip for rapid monitoring of air quality.
Researchers of the St. Petersburg State Electrotechnical University (SPbGETU) "LETI" together with colleagues from the Saratov State Technical University named after Yu. A. Gagarin (SGTU) have created a unique chip that will allow you to diagnose the state of the environment, as well as control the emissions of pollutants into the atmosphere.
Today, special attention is paid to monitoring the content of chemicals in the air. Analysis of the concentration of gases and various impurities in indoor and outdoor areas is necessary for monitoring the state of the environment, controlling the release of pollutants into the atmosphere, as well as for non-invasive diagnostics of respiratory diseases. Usually, special gas analysis systems are used to detect the level of air pollution — expensive and non-mobile.
The joint development of scientists from St. Petersburg State Electrotechnical University "LETI" and Saratov State Technical University named after Yu.A. Gagarin will simplify the process of air diagnostics, make it faster and less expensive. Their invention-a multi-sensor chip weighing only 5 g-is related to the field of sensor technology and nanotechnology.
According to Svetlana Nalimova, Associate Professor of the Department of Micro - and Nanoelectronics at St. Petersburg State Technical University "LETI", one of the creators of the chip, the main difference between their device is that it consists of several adsorption chemoresistive sensors, which allows you to detect the presence of several gases in the air. Existing analogues on the market are able to distinguish only one type of gas.
"Using mathematical processing of signals coming from several sensors, gases are separated. In this invention, this is shown by the example of vapors of organic solvents-acetone, isopropyl alcohol and ethanol. Due to the fact that this invention uses hierarchical structures of zinc oxide in combination with mathematical processing of signals from a line of sensors, it becomes possible to detect and distinguish low gas concentrations, which is impossible to do with other devices in this price category" – she explains.
Role of the scientific group of St. Petersburg State Technical University "LETI" under the leadership of Professor of the Department of Micro-and Nanoelectronics (MNE) Vyacheslav Moshnikov's role in developing a new method for manufacturing a gas-analytical multisensor chip was to prepare gas-sensitive layers for a multisensor device. They are based on hierarchical zinc structures, which have a larger area of the active surface of interaction with the gas of these structures. Due to it, the recorded resistance increases, which determines the presence of gases. This change makes it possible to determine the concentration of impurities in the air with greater accuracy. Scientists from SSTU, in turn, developed algorithms for processing signals from a line of sensors.
"These developments did not come out of nowhere. Prior to this, Svetlana Nalimova's PhD thesis presented theoretical and experimental studies of the possibilities of improving sensory properties by forming sensitive layers with a fractal-percolation structure. Further, in the dissertation work of Anton Bobkov, methods of nanolithography with atomic-molecular design are introduced at the patent level — " says Vyacheslav Moshnikov. — "As a result, the new architectonics of gas-sensitive layers represents a hierarchy in which nanocrystalline rods form nanochannels with fractal-percolation geometry from the constituent nanocrystals. The patent for this invention was recognized as one of the best in the Russian Federation for 2018. The prospects for a multi-sensor chip as a whole are quite obvious-improving the selectivity and sensitivity of gas sensors."
According to scientists, the development can find its place in environmental enterprises during environmental monitoring, in large-scale production when analyzing the state of indoor air, as well as in medical practice. In the future, it can be placed in a small portable device, which will make the equipment for monitoring air quality more mobile and less expensive.