Thermoelectric performance of (AgBiTe2)1-x(SnTe)x with stable cubic enabled by enhanced configurational entropy

ABX(2) (A = Ag, Na, Cu; B = Sb, Bi; X = S, Se, Te) (Groups I-V-VI2) compounds, which are all characterized by the ultralow lattice thermal conductivity because of their strong lattice anharmonicity caused by lone-pair electrons, have aroused wide attention in thermoelectric community. The practical application of thermoelectric devices usually requires both the compatible n-type and p-type materials simultaneously. However, most of I-V-VI2 compounds are intrinsic p-type semiconductors, lacking their n-type counterparts for thermoelectrics. Herein, in this work, we increase the configuration entropy of AgBiTe2 by alloying SnTe, in order to stabilize the cubic phase at room temperature. With further optimization of thermal and electrical performance, the thermoelectric performance could be improved simultaneously in both n- and p-type (AgBiTe2)(1-x)(SnTe)(x) (x = 0.3, 0.4) solid solutions. Finally, p-type compound with the nominal composition of (AgBi0.99Cd0.01Te2)(0.6)(SnTe)(0.4) and n-type of (AgBiTe2)(0.7)(SnTe)(0.3) similar to Br 6% show the maximum zT of similar to 0.33 and similar to 0.21, at 381 and 423 K, respectively.