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. Graphical abstract fx1 Highlights • Dispersed nanodiamonds generate locally concentrated-strain fields in the matrix. • The locally strained interfaces are corresponding to point-defects clustered zones. • Nanoscale clustering of cationic defects results in hole carrier density. • PDZ independently controls thermal conductivity and power factors for improving ZT. [ABSTRACT FROM AUTHOR]