In this paper, a brief review of experimental studies aimed at creating highly efficient thermoelectric materials based on BiCuSeO layered oxyselenides is presented. A brief historical survey is given and the available data on crystal and electronic structures and thermoelectric properties of BiCuSeO oxyselenides is discussed. The main physical ideas and methods used to improve the thermoelectric efficiency of materials based on BiCuSeO are considered.

Polycrystalline alloys Fe₂TiSn_1–xSi_x (0 ≤ x ≤ 1) theoretically predicted as highly efficient thermoelectric materials are experimentally studied. Structural studies show that the partial substitution of Sn with Si results in the formation of a multiphase state in samples with x > 0. Impurity phases in general lead to a significant decrease in the Seebeck coefficient and an increase in the thermal conductivity of Fe₂TiSn_1–xSi_x samples, which does not allow consideration of these materials as promising thermoelectrics.