Dr. Irina Alexandra Vlčková Kühne
The SFN group’s research (Gas Sensors and Functional Nanomaterials) focuses on the development and characterization of new functional materials and the exploration of their gas sensing properties. We are in particular interested in light-active and switchable magnetic materials of transition metals and lanthanides, as well as their surface deposition to prepare thin films towards practical applications such as gas sensing.
Chemical sensors are vital to detect, analyze and remove pollutant and hazardous gases that are not only harmful to humans and animals e.g. ozone and nitrogen oxides but also endanger live on earth in a wider sense.
Our research includes the synthesis and characterization of molecular nanomaterial that are (i) capable of switching between high-spin (HS) and low-spin (LS) states by varying the temperature, pressure or by irradiation (spin crossover complexes), (ii) as well as molecular nano-magnets (single molecule magnets, SMMs) which are capable to exhibit slow magnetic relaxation at low temperatures. In addition, we are interested in bio-mimicking materials, metal organic frameworks (MOFs) and ionic liquids which meet the stringent requirements for new applications in telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups.
A key feature for the application as chemical sensors is the preparation of homogeneous thin films. We are using various deposition techniques (vacuum and wet methods) to understand how different methods perform and to gain an understanding of the optimum conditions. Our laboratory is equipped with a magnetron sputtering (IonTech) and an in-house developed hybrid PVD/CVD device for the deposition of various metals as well as metal oxides. We have experience with various wet processes (e.g. zone-casting, dip-coating and drop casting) and together with our spin-coater (Ossila) that gives us the possibility to control the number of layers, and therefore the thickness of the target film.
The testing of new chemiresistive sensors relies on the conversion of chemical quantities into measurable electronic signals to quantitatively sense hazardous gases. We are able to test the sensing abilities of the thin films towards hazardous gases such as NOx, O3, NH3, CO2 and VOCs using our current measuring system consisting of an in-house developed sensor measurement chamber and measurement system of high precision multimeters to gain information about sensitivity, selectivity, sensor stability, response and recovery time and detection limit.