Electron-Beam Irradiation Enables Concurrent Thermoelectric and Mechanical Enhancement in Commercial p-Type Bi0.5Sb1.5Te3

Abstract

Bi0.5Sb1.5Te3 is the only commercially viable p-type thermoelectric (TE) material for near-roomtemperature applications, yet its performance is constrained by the strong interdependence among electrical conductivity (σ), Seebeck coefficient (S), and thermal conductivity (κ), as well as insufficient mechanical robustness. Here, we report that high-energy electron beam irradiation, a mature and industrially accessible technique, effectively enhances both the TE and mechanical properties of p-type Bi 0.5 Sb 1.5 Te 3 without introducing extrinsic dopants, through defect induction and annealing mechanisms. Electron irradiation simultaneously increases hole concentration and intrinsic defect density, enabling partial decoupling of charge and heat transport and the concurrent optimization of σ, S, and κ. As a result, the irradiated material exhibits markedly improved performance in the 303-403 K range. After a dose of 400 kGy, a room-temperature ZT of ∼1.49, a peak ZT max of ∼1.65 at 353 K, and an avarage ZT avg of ∼1.58 over 303-403 K are achieved, accompanied by an enhanced Vickers hardness of ∼60.79 Hv . This work establishes electron-beam irradiation as an efficient, ecofriendly, and industrially viable route for upgrading commercial p-type Bi0.5Sb1.5Te3 , offering a practical pathway toward large scale TE applications.