Thermoelectricity is one of the eco-friendly and sustainable energy harvesting techniques to address the current energy crisis in the world. The phenomenon is based on converting thermal energy into electrical energy under the effect of a temperature gradient. The enhancement in thermoelectric efficiency has been a key challenge because of the coupling relation between thermal and electrical transport of charge carriers in the material. CoSb3 based skutterudite systems [1] are one of the promising candidates for the intermediate temperature range (300K – 900K) thermeoelctric applications beacause of their caged type complex crystal structure and non-toxic constituting elements. The rattling behaviour of multiple-filler atoms in the voids have shown wide range of phonon scattering phenomena. Higher filling fraction of Yb suppresses the bipolar contribution in Seebeck coefficient and increases the carrier concentration which in turn improves the electrical conductivity. All these effects would render these systems suitable to induce decoupling effects between electrical and thermal transport parameters under phonon glass electron crystal (PGEC) approach [2].Yb0.4Co4Sb12 compound being a well studied system has shown higher electronic performance due to the enhancement in carrier concentration provided by Yb filler atom [3]. The rattling Yb atoms provide lowering effects in thermal conductivity. However, further strategies need to be adopted for enhancement in thermoelectric efficiency. Herein, the effect of Ti at Co site in YbzCo4-xTixSb12 (z = 0, and 0.4 ; x = 0.04, and 0.08) has been studied. The power factor (S2σ) values for doped samples have been found to be enhanced to ~ 44 μW/cm. K2 at ~ 577K. which clearly demonstrates the favorable effect of Ti doping on the thermoelectric performance. This work will focus on the understanding of material physics aspects of these doped phases for harnessing thermoelectric power from thermal energy.

Reference:
1. Xun Shi et al., “Realization of high thermoelectric performance in n-type partially filled skutterudites”, J. Mater. Res., 26, 1745(2011)
2. D. M. Rowe, “CRC handbook of thermoelectrics”, CRC press, 1995
3. Zihang Liu et al., “New insights into the role of dislocation engineering in N-type filled skutterudite CoSb3”, J. Mater. Chem. C,7, 13622(2019)