Spontaneously promoted carrier mobility and strengthened phonon scattering in p-type YbZn2Sb2 via a nanocompositing approach

• Published in: Nano energy 2018-01, Vol.43, p.159-167
• Main Authors: Zhang, Xiong, Zhang, Bin, Peng, Kun-ling, Shen, Xing-chen, Wu, Gui-tai, Yan, Yan-ci, Luo, Shi-jun, Lu, Xu, Wang, Guo-yu, Gu, Hao-shuang, Zhou, Xiao-yuan
• Format: Article
• Language: English
• Subjects: Carrier density; Mobility; Nanocompositing; Phonon scattering; Thermoelectric
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2017.11.019

Conventional strategies for advancing thermoelectrics via nanocompositing focus on the enhanced phonon scattering induced by nanostructured phase. Here, an effective approach of combining carrier mobility promotion and strengthened phonons scattering to simultaneously improve electrical and thermal transport properties is demonstrated. For the p-type YbZn2Sb2 with InSb nanoinclusions, the Hall mobility is effectively enhanced by InSb in the whole measured temperature, from 56cm2V−1s−1 to 162cm2V−1s−1 at 300K. Meanwhile, the carrier density optimization by tuning Yb vacancies leads to 46% improvement in the Seebeck coefficient, overcoming the negative contribution from InSb. Moreover, with the help of interface scattering caused by nanoinclusions, the lattice thermal conductivity is reduced by 45% at 720K. As a result, the thermoelectric figure of merit ZT is enhanced nearly a factor of three. We believe our method provides a “combined strategy” to enhance thermoelectric performance of YbZn2Sb2 based compounds and should be applicable to other thermoelectric materials. This work describes a simple and effective method to simultaneously improve electrical and thermal transport properties by combining carrier mobility promotion and strengthened phonons scattering. [Display omitted] •InSb can effectively enhance the mobility of the composite in the whole measured temperature range.•The stacking sequence of YbZn2Sb2 is firmly confirmed on atomic scale by direct evidence of STEM-EDS mapping.•Electrical and thermal properties were simultaneously improved by promoted mobility and strengthened phonons scattering.•The thermoelectric figure of merit ZT was increased by a factor of three.