Supplementary Information (doc 2270K)

Supporting Information
High Thermoelectric Performance in Copper Telluride
Ying He1,2,3, Tiansong Zhang2, Xun Shi1,2,*, Su-Huai Wei4, Lidong Chen1,2
Heat capacity (Cp)
Cu2Te is a very complicated system. It undergoes five phase transitions from 300 K to
1000 K that can be easily recognized from DSC measurement. There are lots of stable and
meta-stable phases in Cu2Te. Because these phases are very similar in structure and energy, a
small change during sample fabbricating process can affect its structures and phases such as
SPS sinstering. Even for the samples annealed at different temperatures, we can also see the
differences in structures. All the above factors have a direct effect on electrical and thermal
transport properties as well as thermoelectric performance.
Figure S1.Temperature dependence of heat capacity of direct annealed Cu2Te and SPS-Cu2Te.
Figure S2. Anisotropy test on electronic transport properties in Cu2Te directly annealed at
1000 K.
Figure S3. Repeatability test on electronic transport properties in the direct annealed Cu2Te
and SPS Cu2Te samples.
Figure S4. Comparison on carrier mobility in Cu2X (X=S, Se, Te).
Figure S5. Temperature dependence of Lorenz number by assuming L is equal to 0.2 W m-1