Enhancement in the thermoelectric performance by Y substitution on SrSi2

We report the results of the Y substitution in Sr1−xYxSi2 with x≤0.15 via measuring the temperature-dependent electrical resistivity, thermal conductivity, as well as Seebeck coefficient. Upon substituting Y onto the Sr sites, the electrical resistivity exhibit semiconducting behavior and the room-temperature electrical resistivity tends to reduce for x≤0.08. The thermal conductivity also decreases with increasing the Y content. Moreover, the Seebeck coefficient has a substantial increase and a maximum of about 220 μV/K at around 80 K has been found for x=0.08. These promising effects lead to a significant enhancement in the thermoelectric performance characterized by the figure-of-merit, ZT. A room-temperature ZT value of approximately 0.4 is thus achieved for Sr0.92Y0.08Si2, about one order of magnitude larger than that of stoichiometric SrSi2.