Effects of SnSe addition on the thermoelectric properties of Bi_0.85Sb_0.15Se

In this work, the thermoelectric properties of Bi_0.85Sb_0.15Se-x mol% SnSe (x = 0, 1, 5, 10) composites were investigated. As the SnSe content increases, the electrical conductivity σ gradually decreases. This decline can be attributed to the concurrent reduction in both carrier concentration n and carrier mobility μ. In contrast, the absolute Seebeck coefficient |S| experiences a remarkable enhancement, primarily attributed to the combined influence of reduced electron concentration and the energy filtering effect. Consequently, the power factor has undergone a significant improvement. When appropriate SnSe is added, thermal conductivity κ can be suppressed. So the ZT_max of sample x = 10 reaches 0.45 near room temperature, which is a 15.4 % enhancement relative to the pristion sample.