Introducing HfO2 nanoparticles into Bi-Se-Te matrix by cryogenic ball milling for enhanced thermoelectric figure of merit

Abstract Bi 0.3 Sb 1.7 Te 3 alloy particles were synthesized by casting and post-annealing techniques. HfO 2 nanoparticles were synthesized by hydrothermal method. HfO 2 nanoparticles with different volume percentage were dispersed into the Bi 0.3 Sb 1.7 Te 3 matrix by cryogenic ball milling. The distribution of HfO 2 nanoparticles in Bi 0.3 Sb 1.7 Te 3 matrix was confirmed by TEM. The crystallization was determined by XRD. The Bi 0.3 Sb 1.7 Te 3 /HfO 2 composite particles were hot pressed into pellets for thermoelectric property measurement by Physical Properties Measurement System (PPMS). The results showed that when the HfO 2 volume percentage was 0.4%, the composite showed the highest ZT value, which was 30% higher than pure Bi 0.3 Sb 1.7 Te 3 .