Optimisation of Bi₂Te₃-basedmaterials for generation applications

V.L. Kuznetsov¹, L.A.Kuznetsova¹, D.M. Rowe¹, H. Kaibe²

¹Division ofElectronic Engineering, Cardiff University, Cardiff CF2 3TF, UK

²Komatsu Ltd.,1200, Manda, Hiratsuka-shi, Kanagawa 254-8567, Japan

There is a growing interest in thermoelectricrecovery of waste heat into useful electrical power. Requirements foroptimisation of Bi₂Te₃-based materials for thermoelectricgeneration applications over the temperature range 300–500 K arediscussed. The reduction of a negative effect of intrinsic conduction onthermoelectric properties is essential for achieving high figure of meritvalues at temperatures >300 K. Preparation, characterisation andmeasurements of the temperature dependence of transport properties of Bi₂Te₃-basedsolid solutions are reported. The temperature variations of figure of merit areevaluated from the Seebeck coefficient, electrical resistivity and thermalconductivity measurements over the temperature range 300–600 K. Theeffect of solid solution composition, dopant type and concentration on thehigh-temperature transport properties of both n-and p-type materials are determined in a widerange of composition and dopant concentration. The methods are proposed ofpreparation of functionally graded materials with variation of carrierconcentration along the legs’ length to match the temperature gradientalong the thermoelement. The potential for thermoelectric applications of thesematerials is evaluated.