We have developed a new class of bulk thermoelectric materials based on clathrates with a three dimensional framework comprised of oversized transition metal-phosphorus polyhedral cages that encapsulate guest cations. Transition metal-based clathrates have the following advantages over conventional Si-, Ge-, and Sn-based clathrates: i) a larger variety of framework topologies; ii) a higher tunability of the electronic properties via framework substitutions. The correlation between the crystal structure, distribution of the metal and phosphorus atoms over the clathrate framework and thermoelectric properties will be discussed.
Exploration of chemical factors that aﬀect magnetic interactions in solids is one of the major steps in the development of novel magnetic materials. We have developed a synthetic approach that granted access to novel well-crystalline materials containing an inﬁnite Fe-chalcogenide sublattice where correlated magnetic interactions are expected. On the example of the solution synthesis of the simplest superconductor, tetragonal iron(II) selenide (β-FeSe), we will consider main advantages and pitfalls of the solution synthesis of superconductors and highly correlated materials. Perspectives of this method for the design and synthesis of new materials will be discussed.