Abstract Scope |
I will present several examples of effective defect engineering from our lab. Cr doping lowered formation energy of Ge defects, leading to homogenously distributed Ge precipitations and Ge vacancies, enabling a ZT~2 [1]. High-entropy alloying into GeTe, stabilized the cubic phase and defects, thereby enabling enhanced doping of Bi, leading to the first stable n-type conduction in GeTe [2]. The hidden role of rhombohedral distortion degree on Ge-vacancy formation energy was revealed and utilized leading to high power factor and ZTav [3]. Defects also enhanced power factor of Mg2Sn films. Minute Cu doping into grain boundaries and interstitial sites led to ZT enhancement, and an 8 pair module of Mg-Sb-based materials achieving efficiency of 7.3% at a hot side of 320°C rivalling long-time champion Bi2Te3-based module [4].
[1] Small, 16, 1906921 (2020).
[2] NPG Asia Mater., 12:66 (2020).
[3] Adv. Energy Mater., 10, 2002588 (2020).
[4] Joule, 5, 1196 (2021). |