Effects of Cation Site Substitutions on the Thermoelectric Performance of Layered SnBi2Te4 utilizing the Triel Elements Ga, In, and Tl

Abstract

AbstractA thorough study on the thermoelectric potential of the layered compound SnBi2Te4 is presented. Phase range studies on SnBi2Te4, unit cell parameters by powder X‐ray diffraction, and electronic structure calculations (both LDA and GGA functional) were performed. Physical property measurements regarding substitution of tin and bismuth with the triel (Tr = Ga, In, Tl) elements are presented towards the improvement of thermoelectric properties, according to TrxSn1–xBi2Te4 and TrxSnBi2–xTe4. The range of inclusion was generally over 0.01 ≤ x ≤ 0.15 to monitor compound changes as well as phase purity limits. Seebeck coefficient, S, electrical conductivity, σ, and thermal conductivity, κ, were measured, yielding the dimensionless Figure of merit, ZT, data over a temperature range between 300 K and 680 K. Results of partial replacements of tin and bismuth are compared and reported. ZTmax values range from 0.10 to 0.34 depending on the dopant, achieved at temperatures from 355 K to 420 K.