Only 15 years ago the word "nano", which is very common today, was only used by specialists - physicists, chemists and engineers who were the pioneers of nanomaterial research. Some people believe that the next cultural and historical era in the history of humankind will be named "the era of nanotechnologies". However, we still do not quite know what exactly nanotechnologies are and how they help us in our everyday life. Nanotechnologies are a step forward to a new level of knowledge that previously could not be understood either theoretically or practically. Nanomaterials combine processes that are common for atoms and molecules on the one hand, and macro objects – on the other. It is very hard to predict what this combination will be like and its effects.
The staff of the Department of Materials Science and the Industry of Nanosystems of the Faculty of Chemistry of Voronezh State University under supervision of the Dr. habil. in Mathematics and Physics, Professor, Full Member of the Russian Academy of Sciences Valentin Iyevlev, conduct scientific research in Physics and Chemistry in the field of semiconductors and advanced nanomaterials. One of the innovation projects supported by the Russian Science Foundation is aimed at creation of a new generation of gas chemical sensors based on nanocrystal samples of wide-band oxide semiconductors.
To implement this scientific project Valentin Iyevlev built a team of highly qualified specialists from Voronezh State University, Voronezh State Agricultural University and scientists from M.V. Lomonosov Moscow State University. Communication with colleagues from various scientific centres is very important for every scientist - especially when the investigated objects are so specific. The investigation requires a lot of material and intellectual resources and very advanced and costly equipment. Therefore, to reach the target goals the creative collaboration of scientists from various scientific centres is absolutely essential.
Production of high performance gas sensors is one of the fields of the modern knowledge-intensive nanoindustry. Scientists and engineers from the leading industrialised countries of the EU and the USA are contributing to the development of such instruments.
The operating principle of the gas sensors is based on a fundamental physical characteristic of semiconductors – they change their electrical characteristics in different environments. Such environments include electromagnetic fields, heat and ionising emissions, and various gaseous molecules in the atmosphere. Molecules of various substances can deposit on the surface of semiconductors, thus changing their electrical conductivity. As a result, the electrical conductivity value provides information about the environment and presence of any gaseous substances in the atmosphere.
Gas sensors have already been in production. A good example of such instruments is the alcohol detection device used by traffic police.
Many years of research have given way to more sensitive sensors – actually, a million times more sensitive. That means that the tasks that semiconductor sensors can solve have become more complicated and diverse. For example, it is possible to detect concentrations of impurities in the air below the permitted concentration level. Selectivity has also improved: the instrument with sensors not only allows us to determine the presence of any impurities but also to determine what substance exactly it is.
One such instrument is the so called "electronic nose". It can detect explosive substances and drugs. Moreover, gas sensors can identify if an explosive gas such as methane is present in mines, thus allowing an increased level of safety in the mining industry. It can also detect poisonous carbon monoxide and estimate quality and composition of food products.
Medicine is another very important area of application of gas sensors. Voronezh State University scientists have already finished work on creation of an instrument that can identify ketose state of patients suffering from pancreatic diabetes. Its operating principle is based on the fact that people suffering from pancreatic diabetes have a disorder of the carbohydrate metabolism that leads to production of so called ketone bodies (acetone). The instrument invented by Voronezh scientists can detect such bodies in the expired air. Such a method is more accurate and more convenient for use than the one that currently exists. The scientists are very hopeful that they can start production of such instruments both for medical institutions and for everyday use.
Now a team of scientists from Voronezh State University, Voronezh State Agricultural University and Moscow State University are developing a new instrument that will be able to diagnose some oncology diseases. its operation is also based on the carbohydrate metabolism disorder principle. In this case, substances that indicate metabolism disorders - so called biomarkers are produced. On the basis of semiconductor nanostructures you can develop an express diagnostics method based on the expired air analysis. Evidently, the diagnosis is not conclusive but it will be a warning to the patient and his/her doctor and will indicate that a more detailed examination is required. It is very important, as successful treatment of oncology diseases depends a lot on how quickly the diagnosis was made and, the therapy started. Using such simple analysis more people can be examined in a relatively short period of time.
Since the 1950’s when the first semiconductor sensors were created, a revolution has taken place in semiconductor science. Today sensors are tiny instruments that can identify substance concentration and transfer the data online, can identify odours, and the presence of very low concentrations of complicated substances. Nevertheless, three aspects of the existing instruments need to be improved - consumption of energy (and consequently the cost of production) needs to be decreased, whereas sensitivity and selectivity needs to be increased. Solutions of these problems are goals of the team of scientists headed by Professor Valentin Iyevlev.