Thermoelectric properties and anisotropic electronic band structure on the In4Se3−x compounds

Abstract

We report the high thermoelectric figure-of-merit (ZT) on the Se-deficient polycrystalline compounds of In4Se3−x (0.02≤x≤0.5) and the anisotropic electronic band structure. The Se-deficiency (x) has the effect of decreasing the semiconducting band gap and increasing the power factor. The band structure calculation for In4Se3−x (x=0.25) exhibits localized hole bands at the Γ-point and Y-S symmetry line, whereas the significant electronic band dispersion is observed along the c-axis. Here, we propose that the high ZT values on those compounds are originated from the anisotropic electronic band structure as well as Peierls distortion.

Advances in Thermoelectric Energy Conversion Nanocomposites

“…Moreover, the power factor will increase with increaing Se deficiency between 300 K and 750 K. The power factor of In 4 Se 3-x measured may be lower than that of double-doped skutterudites because of relativiely high electrical resistivity of In 4 Se 3-x. In the same temperature range, the ZT value of In 4 Se 3-x due to high Seebeck coefficient and low thermal conductivity is comparable to the n-type PbTe and CoSb 3 (Rhyee et al, 2009) .…”

Thermoelectric Properties of Spark Plasma-Sintered In4Se3-In4Te3

“…8,9 Consequently, In 4 Se 3 can possess a very low thermal conductivity of less than 1.0 W/mK. [1][2][3] Interestingly, the space group of In 4 Te 3 is D2h 12 -P nnm , the same as that of In 4 Se 3 . 10 Therefore, as in In 4 Se 3 , a low thermal conductivity due to the lowdimensional structure can be expected in In 4 Te 3 .…”

“…The electrical conductivity (r) of In 4 Se 3 with a small direct band gap of 0.2 eV can be controlled by Se-deficient self-doping. 2 A high negative Seebeck coefficient (S) of up to À500 lV/K has been reported, and it is also affected by the self-doping conditions. 2 Thermal conductivity is a very important factor to obtain high thermoelectric performance.…”

“…2 A high negative Seebeck coefficient (S) of up to À500 lV/K has been reported, and it is also affected by the self-doping conditions. 2 Thermal conductivity is a very important factor to obtain high thermoelectric performance. 4,5 It has been reported that very low thermal conductivity (j) can be obtained due to the unique features of the low-dimensional structure of In 4 Se 3 .…”

“…[1][2][3] The performance of a thermoelectric material can be quantified by the dimensionless figure of merit, ZT = S 2 rT/j, where S, r, T, and j are the Seebeck coefficient, electrical conductivity, absolute temperature, and thermal conductivity, respectively. The electrical conductivity (r) of In 4 Se 3 with a small direct band gap of 0.2 eV can be controlled by Se-deficient self-doping.…”