title: n-Type Bi2Te3-xSex Nanoplates with Enhanced Thermoelectric Efficiency Driven by Wide-Frequency Phonon Scatterings and Synergistic Carrier Scatterings.
abstract: Driven by the prospective applications of thermoelectric materials, massive efforts have been dedicated to enhancing the conversion efficiency. The latter is governed by the figure of merit (ZT), which is proportional to the power factor (S(2)σ) and inversely proportional to the thermal conductivity (κ). Here, we demonstrate the synthesis of high-quality ternary Bi2Te3-xSex nanoplates using a microwave-assisted surfactant-free solvothermal method. The obtained n-type Bi2Te2.7Se0.3 nanostructures exhibit a high ZT of 1.23 at 480 K measured from the corresponding sintered pellets, in which a remarkably low κ and a shift of peak S(2)σ to high temperature are observed. By detailed electron microscopy investigations, coupled with theoretical analysis on phonon transports, we propose that the achieved κ reduction is attributed to the strong wide-frequency phonon scatterings. The shifting of peak S(2)σ to high temperature is due to the weakened temperature dependent transport properties governed by the synergistic carrier scatterings and the suppressed bipolar effects by enlarging the band gap.
authors.affiliation: Materials Engineering, University of Queensland , Brisbane, Queensland 4072, Australia.
authors.forename: Min
authors.initials: M
authors.lastname: Hong
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.|Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Chasapis
authors.affiliation: Materials Engineering, University of Queensland , Brisbane, Queensland 4072, Australia.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Chen
authors.affiliation: Materials Engineering, University of Queensland , Brisbane, Queensland 4072, Australia.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: G Jeffrey
authors.initials: GJ
authors.lastname: Snyder
authors.affiliation: Materials Engineering, University of Queensland , Brisbane, Queensland 4072, Australia.|Centre for Microscopy and Microanalysis, University of Queensland , Brisbane, Queensland 4072, Australia.
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
keywords: Bi2Te3−xSex; nanostructuring; synergistic carrier scatterings; thermoelectric; wide-frequency phonon scatterings