Impact of melt solidification rate on structural and thermoelectric properties of n-type Bi2Te3 alloy

Alloys based on bismuth telluride (Bi2Te3) form an important class of thermoelectric materials used in Peltier cooling devices and thermoelectric generators. In this work, polycrystalline n-type Bi2Te3 alloy was prepared by a melt-quenching process using different quenching mediums: alkaline ice water, ice water, normal water, liquid nitrogen, and air-cooling. The relation between melt solidification rate and structural and thermoelectric transport properties of Bi2Te3 alloy were studied. The pure phase of Bi2Te3 is confirmed by structural characterizations: XRD and Raman. This study showed that the melt solidification rate has a consequential role in modulating the microstructure and thermoelectric transport properties. The moderate cooling rate of melt solidification showed the highest zT of similar to 0.06 at 423 K due to higher defect density. This study attempts to explain the different zT values observed for different quenching mediums.

Automated summary

This study prepared n-type Bi2Te3 alloy using different quenching mediums and investigated the influence of melt solidification rate on its structure and thermoelectric transport properties. The moderate cooling rate of melt solidification showed the highest zT value.