We have located links that may give you full text access.
JOURNAL ARTICLE
RESEARCH SUPPORT, NON-U.S. GOV'T
Low Thermal Conductivity and High Thermoelectric Performance in (GeTe) 1-2x (GeSe) x (GeS) x : Competition between Solid Solution and Phase Separation.
Journal of the American Chemical Society 2017 July 13
GeTe and its derivatives constituting Pb-free elements have been well known as potential thermoelectric materials for the last five decades, which offer paramount technological importance. The main constraint in the way of optimizing thermoelectric performance of GeTe is the high lattice thermal conductivity (κlat ). Herein, we demonstrate low κlat (∼0.7 W/m·K) and a significantly high thermoelectric figure of merit (ZT = 2.1 at 630 K) in the Sb-doped pseudoternary (GeTe)1-2x (GeSe)x (GeS)x system by two-step strategies. The (GeTe)1-2x (GeSe)x (GeS)x system provides an excellent podium to investigate competition between an entropy-driven solid solution and enthalpy-driven phase separation. In the first step, small concentrations of Se and S were substituted simultaneously in the position of Te in GeTe to reduce the κlat by phonon scattering due to mass fluctuations and point defects. When the Se/S concentration increases significantly, the system deviates from a solid solution, and phase separation of the GeS1-x Sex (5-20 μm) precipitates in the GeTe1-x Sex matrix occurs, which does not participate in phonon scattering. In the second stage, κlat of the optimized sample is further reduced to 0.7 W/m·K by Sb alloying and spark plasma sintering (SPS), which introduce additional phonon scattering centers such as excess solid solution point defects and grain boundaries. The low κlat in Sb-doped (GeTe)1-2x (GeSe)x (GeS)x is attributed to phonon scattering by entropically driven solid solution point defects rather than conventional endotaxial nanostructuring. As a consequence, the SPS-processed Ge0.9 Sb0.1 Te0.9 Se0.05 S0.05 sample exhibits a remarkably high ZT of 2.1 at 630 K, which is reproducible and stable over temperature cycles. Moreover, Sb-doped (GeTe)1-2x (GeSe)x (GeS)x exhibits significantly higher Vickers microhardness (mechanical stability) compared to that of pristine GeTe.
Full text links
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app