Suppression of bipolar excitation and enhanced thermoelectric performance in n-type Bi2Te3 with argyrodite Ag8SnSe6 inclusion

Abstract

In the ever-evolving landscape of electronic cooling technologies, thermoelectric materials have emerged as crucial contenders for efficient heat dissipation. Bi₂Te₃-based materials are the most outstanding for room temperature application. However, to achieve efficient heat dissipation, the properties of n-type Bi₂Te₃ need to be improved. This study introduces a novel approach utilizing argyrodite semiconductor Ag₈SnSe₆ (STSe) to enhance the thermoelectric properties of n-type Bi_1.995Cu_0.005Te_2.69Se_0.33Cl_0.03. The sample 0.5 wt% STSe achieved a Seebeck coefficient of −193.57 μV K⁻¹ at 353 K due to enhancement in the DOS effective mass caused by dissolved Ag and Sn. In addition, the thermal conductivity of the matrix is reduced by 21.19% to 0.74 W m⁻¹ K⁻¹ at 353 K, owing to Ag_Bi and Sn_Bi, dislocations and STSe nanoscale particles. Consequently, we achieved a room temperature ZT value of 1.17, a peak ZT value of 1.24 at 353 K, and an average ZT of 1.15 in the 300–500 K range due to suppression of bipolar excitation.