Vacancy-Based Defect Regulation for High Thermoelectric Performance in Ge9Sb2Te12–x Compounds

• DOI: 10.1021/acsami.0c02155
• Publication Date: 2020-04-07T17:50:35Z
• Authors: Shuo Chen; Hui Bai; Junjie Li; Wenfeng Pan; Xianyan Jiang; Zhi Li; Zhiquan Chen; Yonggao Yan; Xianli Su; Jinsong Wu; Ctirad Uher; Xinfeng Tang
• Keywords: 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences; 0104 chemical sciences

Defect engineering is the core strategy for improving thermoelectric properties. Herein, cation doping along with modulation of vacancy has been developed in GeTe-based materials as an effective method to induce vacancy-based defects boost their performance. A series ternary compounds Ge9Sb2Te12-x (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15) was prepared by vacuum-melting and annealing combined spark plasma sintering (SPS) process. The role Sb on properties systematically investigated. It found that alloying Sb2Te3 into GeTe increases concentration vacancies, which corroborated both positron annihilation measurements theoretical calculations. stacking faults, planar defect interactions determine transport Adjusting deficiency Te effectively tunes vacancies dopant structure. In turn, this carrier close its optimum. high power factor 32.6 μW cm-1 K-2 realized Ge9Sb2Te11.91 at 725 K. Moreover, large strains induced structures, including dopant, vacancy, staking well intensify phonon scattering, leading a significant decrease thermal conductivity from 7.6 W m-1 K-1 pristine 1.18 Ge9Sb2Te11.85 room temperature. All above contribute ZT value 2.1 achieved sample 775