title: Engineering Band Structure via the Site Preference of Pb(2+) in the In(+) Site for Enhanced Thermoelectric Performance of In6Se7.
abstract: Although binary In-Se based alloys have in recent years gained interest as thermoelectric (TE) candidates, little attention has been paid to In6Se7-based compounds. Substituting Pb in In6Se7, preference for Pb(2+) in the In(+) site has been observed, allowing Fermi level (Fr) shift toward the conduction band, where the localized state conduction becomes dominant. Consequently, the Hall carrier concentration (nH) has been significantly enhanced with the highest nH value being about 2-3 orders of magnitude higher than that of the Pb-free sample. Meanwhile, the lattice thermal conductivity (κL) tends to be reduced as the nH value increases, owing to an increased phonon scattering on carriers. As a result, a significantly enhanced TE performance has been achieved with the highest TE figure of merit (ZT) of 0.4 at ∼850 K. This ZT value is 27 times that of intrinsic In6Se7 (ZT = 0.015 at 640 K), which proves a successful band structure engineering through site preference of Pb in In6Se7.
authors.affiliation: School of Materials & Chemical Engineering, Ningbo University of Technology , Ningbo 315016, China.
authors.forename: Jiaolin
authors.initials: J
authors.lastname: Cui
authors.affiliation: School of Materials & Chemical Engineering, Ningbo University of Technology , Ningbo 315016, China.|Materials Science and Engineering College, Taiyuan University of Technology , Taiyuan 030024, China.
authors.forename: Min
authors.initials: M
authors.lastname: Cheng
authors.affiliation: School of Materials & Chemical Engineering, Ningbo University of Technology , Ningbo 315016, China.
authors.forename: Wenchang
authors.initials: W
authors.lastname: Wu
authors.affiliation: School of Materials & Chemical Engineering, Ningbo University of Technology , Ningbo 315016, China.
authors.forename: Zhengliang
authors.initials: Z
authors.lastname: Du
authors.affiliation: School of Chemistry, University of East Anglia , Norwich NR4 7TJ, United Kingdom.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Chao
keywords: In6Se7; band structure engineering; carrier concentration; fermi level; site preference; thermoelectric performance