Enhanced thermoelectric performance of highly oriented polycrystalline SnSe based composites incorporated with SnTe nanoinclusions

• P-type polycrystalline SnSe with highly preferred orientation is prepared.
• Polycrystalline SnSe with highly preferred orientation has a high ZT value.
• Incorporation of SnTe nanoinlusions into SnSe matrix enhances the power factor.

Binary single crystal compound SnSe with high thermoelectric performance has drawn great attention to polycrystalline SnSe. Here, we synthesized highly oriented p-type polycrystalline composite samples f mol% SnTe/Ag0.005Sn0.995Se (f = 0, 0.5, 1 and 1.5) and present thermoelectric performance from 300 K to 900 K. High thermoelectric figure of merit (ZT) of the matrix Ag0.005Sn0.995Se should be attributed to highly oriented crystal grains along the (400) plane. Moreover, proper proportional (f = 0.5) incorporation of SnTe nanoinlusions into Ag0.005Sn0.995Se matrix enhances the power factor and reduces lattice thermal conductivity, which could be due to the contribution of enhanced phonon scattering resulting from abundant interfaces. Consequently, a largest ZT value of 1.6 ± 0.2 is achieved at 875 K for composite sample 0.5 mol% SnTe/Ag0.005Sn0.995Se. Furthermore, these polycrystalline composites have large values of ZT (>1) from 800 K to 900 K and good experimental repeatability, which suggests that it is a promising candidate for high temperature power generation.