TY - JOUR
T1 - Band Degeneracy, Low Thermal Conductivity, and High Thermoelectric Figure of Merit in SnTe-CaTe Alloys
AU - Al Rahal Al Orabi, Rabih
AU - Mecholsky, Nicolas A.
AU - Hwang, Junphil
AU - Kim, Woochul
AU - Rhyee, Jong Soo
AU - Wee, Daehyun
AU - Fornari, Marco
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2016/1/12
Y1 - 2016/1/12
N2 - Pure lead-free SnTe has limited thermoelectric potentials because of the low Seebeck coefficients and the relatively large thermal conductivity. In this study, we provide experimental evidence and theoretical understanding that alloying SnTe with Ca greatly improves the transport properties leading to ZT of 1.35 at 873 K, the highest ZT value so far reported for singly doped SnTe materials. The introduction of Ca (0-9%) in SnTe induces multiple effects: (1) Ca replaces Sn and reduces the hole concentration due to Sn vacancies, (2) the energy gap increases, limiting the bipolar transport, (3) several bands with larger effective masses become active in transport, and (4) the lattice thermal conductivity is reduced by about 70% due to the contribution of concomitant scattering terms associated with the alloy disorder and the presence of nanoscale precipitates. An efficiency of ∼10% (for ΔT = 400 K) was predicted for high-temperature thermoelectric power generation using SnTe-based p- and n-type materials.
AB - Pure lead-free SnTe has limited thermoelectric potentials because of the low Seebeck coefficients and the relatively large thermal conductivity. In this study, we provide experimental evidence and theoretical understanding that alloying SnTe with Ca greatly improves the transport properties leading to ZT of 1.35 at 873 K, the highest ZT value so far reported for singly doped SnTe materials. The introduction of Ca (0-9%) in SnTe induces multiple effects: (1) Ca replaces Sn and reduces the hole concentration due to Sn vacancies, (2) the energy gap increases, limiting the bipolar transport, (3) several bands with larger effective masses become active in transport, and (4) the lattice thermal conductivity is reduced by about 70% due to the contribution of concomitant scattering terms associated with the alloy disorder and the presence of nanoscale precipitates. An efficiency of ∼10% (for ΔT = 400 K) was predicted for high-temperature thermoelectric power generation using SnTe-based p- and n-type materials.
UR - http://www.scopus.com/inward/record.url?scp=84954422129&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.5b04365
DO - 10.1021/acs.chemmater.5b04365
M3 - Article
AN - SCOPUS:84954422129
SN - 0897-4756
VL - 28
SP - 376
EP - 384
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 1
ER -