Manipulation of ionized impurity scattering for achieving high thermoelectric performance in n-type Mg3Sb2-based materials

Jun Mao, Jing Shuai, Shaowei Song, Yixuan Wu, Rebecca Dally, Jiawei Zhou, Zihang Liu, Jifeng Sun, Qinyong Zhang, Clarina Dela Cruz, Stephen Wilson, Yanzhong Pei, David J. Singh, Gang Chen, Ching Wu Chu, Zhifeng Ren

Research output: Contribution to journalArticlepeer-review

Abstract

Achieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type Mg3Sb2-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved. In this work, Fe, Co, Hf, and Ta are doped on the Mg site of Mg3.2Sb1.5Bi0.49Te0.01, where the ionized impurity scattering crosses over to mixed ionized impurity and acoustic phonon scattering. A significant improvement in Hall mobility from ∼16 to ∼81 cm2·V−1·s1 is obtained, thus leading to a notably enhanced power factor of ∼13 μW·cm−1·K−2 from ∼5 μW·cm−1·K−2. A simultaneous reduction in thermal conductivity is also achieved. Collectively, a figure of merit (ZT) of ∼1.7 is obtained at 773 K in Mg3.1Co0.1Sb1.5Bi0.49Te0.01. The concept of manipulating the carrier scattering mechanism to improve the mobility should also be applicable to other material systems.

Original languageEnglish
Pages (from-to)10548-10553
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number40
DOIs
Publication statusPublished - 2017 Oct 3

All Science Journal Classification (ASJC) codes

  • General

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