High Thermoelectric Performance of Bi-Doped Mg2Si0.4Sn0.6 and Mg2Si0.6Sn0.4 based on Recyclable Si Kerf Derived from PV Manufacturing

In an endeavor to promote semiconductor materials recycling, Bi-doped Mg₂Si_0.4Sn_0.6 and Mg₂Si_0.6Sn_0.4 thermoelectric compounds were synthesized by mechanical alloying using two types of processed Si kerf derived from the photovoltaic manufacturing industry. Powder X-ray diffraction and SEM analysis provided a better understanding of the final phase formation. Rietveld refinements revealed structural changes and the existence of Mg atoms at the interstitial site 4b, which seem to strongly affect the electrical transport properties of investigated materials. High thermoelectric performance of the materials synthesized using Si kerf was obtained, reaching a maximum power factor of 33.2 μW cm^–1 K^–2 and a ZT of 1.1 at 773 K. Achieving such promising thermoelectric properties by replacing commercial, high-purity Si with Si kerfs in the production of Mg₂(Si,Sn) shows that we successfully followed a circular approach that utilizes recyclable materials and reuses byproducts of industrial processes for the development of high-performance thermoelectrics for waste heat recovery, contributing effectively to the overall goal of achieving sustainability in the emerging field of materials for green energy technologies.