Fig shows the temperature dependence of
Fig. 7 shows the temperature dependence of the α for the MAHP samples. The α value firstly increases from 25 °C to 125 °C, and then reduces rapidly when further increasing to 200 °C. This trend is due to intrinsic excitation at higher testing temperatures (125 °C). The α value of p-type thermoelectric materials can be expressed as α=kB/e (δ+C−ln n), where kB is the Boltzmann constant, δ the scattering related factor, e the 6-Iodonordihydrocapsaicin charge, C a constant and n carrier concentration. With increasing holding time, the n value reduces from 2.1×1019 cm−3 to 1.8×1019 cm−3. Therefore, although the δ value decreases due to the increase of grain size, the α value increases as increasing holding time. With increasing sintering temperature, the α value firstly increases slightly and then decreases. When the sintering temperature was increased from 325 °C to 375 °C, the slight increase in α is reproductive isolating mechanism due to the slight decrease in n. When the sintering temperature was higher than 375 °C, the drastical decrease in α can be attributed to the obvious increase in n due to Te vaporization.