InSb-based materials are promising thermoelectric (TE) alternatives at medium temperature with the high power factor (PF) derived from the intrinsically ultra-high mobility (104–105 cm2 V−1 s−1). N-type InSb-based TE materials have been studied extensively due to the intrinsic Sb vacancies originating from the low formation energy. Based on that π-type TE devices are in favor of P-, N-legs with similar thermal expansivity, P-type InSb-based materials are highly desired. Herein, P-type InSb is synthesized by adjusting the Fermi energy via performing Cd doping. The PF reaches up to ~1.91 × 10−3 W m−1 K−2 at 723 K due to the increased electrical conductivity and inhibited bipolar diffusion effect caused by the high carrier concentration. Furthermore, the lattice thermoelectric conductivity is reduced to 2.0 W m−1 K−1 at 723 K on account of intensive phonon scattering and suppressed bipolar diffusion effect. Finally, benefiting from the simultaneous optimization of the electrical and thermal properties, the optimized figure of merit (zT) value of 0.40 (increased by ~7.0 times) at 723 K was achieved in P-type Cd0.07In0.93Sb, which is comparable with most N-type InSb-based materials. This study could be significant to develop cognate thermostable TE devices using the P-type InSb counterparts.

SnTe has received considerable attention as an environmentally friendly alternative to the representative thermoelectric material of PbTe. However, excessive hole carrier concentration in SnTe results in an extremely low Seebeck coefficient and high thermal conductivity, which makes it exhibit relatively inferior thermoelectric properties. In this work, the thermoelectric performance of p-type SnTe is enhanced through regulating its energy band structures and reducing its electronic thermal conductivity by combining Bi doping with CdSe alloying. First, the carrier concentration of SnTe is successfully suppressed via Bi doping, which significantly decreases the electronic thermal conductivity. Then, the convergence and flattening of the valence band by alloying CdSe effectively improves the effective mass of SnTe while restraining its carrier mobility. Consequently, the electronic thermal conductivity is markedly reduced. Finally, a maximum ZT of ~ 0.87 at 823 K and an average ZT of ~ 0.51 at 300-823 K have been achieved in Sn0.96Bi0.04Te-5%CdSe. Our results indicate that decreasing the electronic thermal conductivity is an effective means of improving the performance of thermoelectric materials with a high carrier concentration.