Design, synthesis and characterization of responsive solid-state materials

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Responsive materials exhibit unique physical responses under applied forces or fields. Combination of such physical responses with outstanding mechanical properties of solid-state phases yields functional materials that find applications both at the industrial and consumer levels. The research will focus on two areas of responsive solid-state materials: thermoelectric phases and inorganic phosphors. ***Thermoelectric materials generate voltage when subject to a temperature gradient or perform cooling/heating when current is passed through them. Currently, thermoelectric materials are used for power generation in deep-space mission, remote weather and navigation systems, and for cooling in electronic devices and car seats. And since more than half of the energy is lost as a waste heat, research efforts start to focus on recovering some of this energy, especially in cars and large industrial operations, through thermoelectric generators. Our goal is to develop high-performance thermoelectric materials for the waste heat recovery.***Phosphor materials are extensively used for the LED and fluorescent lighting, where they downconvert the blue or UV radiation into green, yellow and red light. Another growing application of phosphors is temperature measurement; a phosphor is illuminated by a laser and the lifetime of the emitted lower-energy light is measured. The lifetime is temperature dependent and its value yields the temperature. Phosphors allow temperature sensing at large distances and in the environments were other techniques cannot be used, e.g. in electrical transformers, underground during oil or gas extraction. There is demands for phosphors that have long lifetimes, can operate in a wide temperature range and in chemically harsh environments. Additionally, the same phosphors can be used for lighting. Since there is no Canadian research presence in this area, we propose to develop a competitive program on inorganic phosphors.***The short term goals of the proposed research will be discovery and characterization of novel, high-performance thermoelectric materials and phosphors. In the long run, we aim to develop a deeper understanding of the composition-structure-property relationship in these types of materials, and to use the obtained knowledge for the rapid and targeted design of new materials.***In the thermoelectric field, we will pursue synthesis of novel high-temperature thermoelectric (RE,Ca)mPnnOm pnictide oxides (RE is a rare earth, Pn is Sb or Bi) and will expand this series to other pnictides. Research on (RE,Ca)mPnnOm was pioneered in our group and we would like to maintain our leading role in this area.***Among the inorganic phosphors, we will focus on the targeted synthesis of new phosphorescent oxyfluorides of Mg, Ge and Pb, which would permit incorporation of bright emitters (such as Mn4+) with long lifetimes. Another parallel direction is development of chemically inert phosphors that can operate in a wide temperature range.**