材料科学
妥协
热电效应
光电子学
工程物理
纳米技术
热力学
社会科学
物理
工程类
社会学
作者
Richard Liang,Yan Gan,Yang Geng,Lipeng Hu,Fusheng Liu,Weiqin Ao,Chaohua Zhang
标识
DOI:10.1002/adfm.202404021
摘要
Abstract Resonant levels (RLs) are expected to increase the density of states (DOS) abruptly, thereby increasing the Seebeck coefficient for a high thermoelectric figure of merit ( ZT ). However, the negative effects of RLs on reducing the carrier mobility and band gap have rarely been explored. In this work, the pros and cons of resonant‐state doping of group IIIA elements (In, Ga) in GeTe‐based alloys are studied by experimental transport properties and density‐functional‐theory calculations. RLs effects of Fermi level pinning and increased effective mass are strong in Ge 0.9‐x In x Sb 0.1 Te but weak in Ge 0.9‐y (In 0.5 Ga 0.5 ) y Sb 0.1 Te, which shows dependence on the hump DOS relative to the background, location of RLs, and energy width of RLs. Using the In‐Ga co‐doping strategy to make a compromise between the DOS, carrier mobility, and bipolar transport, combined with beneficial alloying effects of Pb and Sb, a peak ZT ≈ 2.1 at 773 K and a high average ZT ≈ 1.43 within 300–773 K can be obtained in Ge 0.78 In 0.005 Ga 0.005 Pb 0.1 Sb 0.07 Te. The corresponding single‐leg device shows a remarkable energy conversion efficiency of 13.7% at a temperature difference of 451 K. This work suggests that RLs are not always beneficial for improving ZT , and the compromise design of RLs should be carefully considered to advance ZT .
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