Carrier-phonon decoupling in perovskite thermoelectrics via entropy engineering.

ABSTRACT: Thermoelectrics converting heat and electricity directly attract broad attentions. To enhance the thermoelectric figure of merit, zT, one of the key points is to decouple the carrier-phonon transport. Here, we propose an entropy engineering strategy to realize the carrier-phonon decoupling in the typical SrTiO₃-based perovskite thermoelectrics. By high-entropy design, the lattice thermal conductivity could be reduced nearly to the amorphous limit, 1.25 W m^-1 K^-1. Simultaneously, entropy engineering can tune the Ti displacement, improving the weighted mobility to 65 cm² V^-1 s^-1. Such carrier-phonon decoupling behaviors enable the greatly enhanced μ_W/κ_L of ~5.2 × 10³ cm³ K J^-1 V^-1. The measured maximum zT of 0.24 at 488 K and the estimated zT of ~0.8 at 1173 K in (Sr_0.2Ba_0.2Ca_0.2Pb_0.2La_0.2)TiO₃ film are among the best of n-type thermoelectric oxides. These results reveal that the entropy engineering may be a promising strategy to decouple the carrier-phonon transport and achieve higher zT in thermoelectrics.

SUBMITTER: Zheng Y 

PROVIDER: S-EPMC11369264 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature