Abstract:
The rapidly depleting available energy resources have led to an increased research focus on the
development of alternative energy sources. In this aspect, research on the development of
efficient thermoelectric (TE) materials and integrating them into devices has taken a lead role
in recent years worldwide. Thermoelectricity is a phenomenon of conversion of thermal energy
into electrical energy and vice versa. The conversion efficiency of a TE material is dependent
on a dimensionless parameter known as the figure of merit zT, which is directly related to the
product of electrical conductivity (σ) and the square of the Seebeck coefficient (S) whereas
inversely related to the thermal conductivity (κ).
This research contains two studies. In the first studies, we explore in-situ lamellar composites
of (Cu2Te) 62.02-(Sb2Te3)37.98 produced by directional solidification using a modified Bridgman
apparatus and its effect on the thermoelectric properties. The eutectic microstructure under
higher growth rates exhibits a cellular microstructure due to growth instability (and hence
segregation at cell boundaries) with cell spacing varying with growth rates. Further, a
quantitative evaluation of the scale of the microstructure in terms of interlamellar spacings
allows us to evaluate the role of the microstructure in tuning the thermoelectric properties as a
function of temperature. An additional significant observation of the present work is a
relatively mild variation of the power factor across a range of temperatures (300 K to 600 K)
in this eutectic system along the transverse direction.
In the second study, we report the microstructure and thermoelectric Properties Of
(Cu2Te)X(Sb2Te3)100-x pseudobinary system synthesized by brine quenching method and
compare the microstructure and transport properties to the same composition synthesized by
solid-state synthesis.
