Enhanced thermoelectric performance via the solid solution formation: The case of pseudobinary alloy (Cu2Te)(Ga2Te3)3 upon Sb substitution for Cu

Abstract

In this work we have observed the beneficial effect from the solid solution formation on the thermoelectric performance of (Cu2(1-x)Sb2xTe)(Ga2Te3)3 upon Sb substitution for Cu. This substitution allows the mixed occupations of Sb in the crystal lattice, i.e. Sb at Cu sites with x≤0.05 and at Ga sides with x≥0.05, which has resulted in the Pisarenko relation does not exactly capture the measured Seebeck coefficient under assumed effective masses m*. The reduction of the lattice thermal conductivity (κL) has been quantified within the temperature range from room temperature to 723 K. Over the entire composition range, the κL value is reduced by 33% and 25% at temperature 723 K and 580 K, respectively. This observation is in a good agreement with the theoretical calculation based on the Callaway model used in the solid solutions. Along with the increasing of the mobility and electrical conductivity, the thermoelectric performance has been improved with the highest ZT value of 0.58 at 723 K, which is about double the value of intrinsic (Cu2Te)(Ga2Te3)3. Keywords: IntroductionAlthough the transformation of waste heat into useful electric power is very attractive so far, the conversion effectiveness is still low because of poor thermoelectric (TE) performance of the materials. Therefore, searching for new materials is one of the great challenges facing the members of TE research community. The TE performance is directly dependent on the dimensionless figure of merit (ZT),

Improvement of Mechanical and Thermoelectric Properties of AgCuTe by Pinning Effect and Enhanced Liquid-Like Behavior via SiC Alloying

“…The increase in p H is primarily attributed to the increase in distortion energy in AgCuTe samples after SiC alloying, enhancing the liquid-like behavior of Ag/Cu atoms. The activation energies for Ag + and Cu + are notably small, measuring 0.21 and 0.26 eV, respectively. − After the introduction of SiC into the AgCuTe matrix, these dispersed nano-SiC will produce a strong lattice distortion energy for the surrounding lattice. This energy provides adequate activation energy for the Ag and Cu atoms in the matrix, enabling their escape from the lattice.…”