1. Rational Design of Cu Vacancies and Antisite Defects for Boosting the Thermoelectric Properties of CuGaTe2-Based Compounds
- Author
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Tang, Yingfei, Liu, Keke, Liao, Lin, Wu, Jinsong, Su, Xianli, Zhang, Qingjie, Poudeu, Pierre Ferdinand Poudeu, and Tang, Xinfeng
- Abstract
CuGaTe2-based compounds show great promise in the application for high-temperature thermoelectric power generation; however, its wide bandgap feature poses a great challenge for enhancing thermoelectric performance via structural defects modulation and doping the system. Herein, it is discovered that the presence of GaCuantisite defects in the CuGaTe2compound promotes the formation of Cu vacancies, and vice versa, which tends to form the charge-neutral structure defects combination with one GaCuantisite defect and two Cu vacancies. The accumulation of Cu vacancies in the structure of the (Cu2Te)x(Ga2Te3)1–xcompounds evolves into twins and stacking faults. This in conjunction with GaCuantisite defects intensify the point defects phonon scattering, yielding a dramatic reduction on lattice thermal conductivity from 6.95 W m–1K–1for the pristine CuGaTe2sample to 2.98 W m–1K–1for the (Cu2Te)0.45(Ga2Te3)0.55sample at room temperature. Furthermore, the high concentration of charge-neutral defects combination narrows the band gap and increases the carrier concentration, leading to an improved power factor of 1.58 mW/mK2at 600 K for the (Cu2Te)0.49(Ga2Te3)0.51sample, which is 41% higher than for the pristine CuGaTe2sample. Consequently, the highest ZTvalue of 0.82 is achieved at 915 K for Cu0.015(Cu2Te)0.48(Ga2Te3)0.52, which represents an enhancement of about 22% over that of the pristine CuGaTe2compound.
- Published
- 2024
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