Strain-mediated point defects in thermoelectric p-type bismuth telluride polycrystalline

Abstract

Intensive efforts to engineer the microstructures of materials by utilizing atomic-scale defects have been made to overcome the current limitation on physical properties such as thermoelectric energy conversion performance levels (ZT). Here, we report that (i) internally dispersed strains are generated by a nano-diamond (ND) inserted into polycrystalline Bi-Sb-Te (BST) alloys, which thereby create point-defects clustered zones (PDZs) around the ND/BST interface; (ii) a local strain field is also generated, wherein many point defects are intensified; (iii) locally-strained interfaces result in an increase of the hole carrier concentration caused by the formation of cationic defects. From these results, strain-mediated point defects in ND particle-dispersed BST matrix (ND/BST) composites are assessed as artificial nanostructures, which can independently control transport properties of carriers and phonons. Our findings open new avenues for design and applications of favorable atomic-defect-structures in the area of energy or electronic materials through a classical solid-state sintering method.