Enhanced thermoelectric performance of N-type eco-friendly material Cu1-xAgxFeS2 (x=0-0.14) via bandgap tuning
Enhanced thermoelectric performance of N-type eco-friendly material Cu1-xAgxFeS2 (x=0-0.14) via bandgap tuning
复制标题
通过带隙调节增强N型环保材料Cu1-xAgxFeS2 (x=0-0.14)的热电性能
DOI：
10.1016/j.jallcom.2019.151717
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发表时间：
2019-11-15
影响因子：
6.2
通讯作者：
Qiao, Guanjun
中科院分区：
文献类型：
--
作者：
Ge, Bangzhi;Shi, Zhongqi;Qiao, Guanjun
CuFeS2是一种环保的n型热电（TE）材料，但性能较差。值得注意的是，带隙（E-g）的减小可以提高载流子迁移率（mu H），从而进一步导致更高的电导率（sigma）和功率因数（PF）。密度泛函理论（DFT）计算结果表明，在CuFeS2化合物中掺银可以缩小Eg。为此，采用真空熔炼与等离子体激活烧结相结合的方法制备了一系列Cu1-xAgxFeS2 （x=0-0.14）合金，并通过带隙调谐途径提高了其TE性能。可以发现，随着银掺杂物含量的增加，Eg确实从0.45 eV缩小到0.39 eV，并且在载流子浓度不降低的情况下，Eg的减少导致mH明显增强。由于mH升高，可以获得更高的PF (0.76 x 10(-3) Wm(-1)K(-2))，并且在Cu0.88Ag0.12FeS2样品中，在723 K处达到峰值ZT值0.45。因此，带隙调谐可以看作是提高CuFeS2的TE性能的有效策略。(C) 2019 Elsevier B.V.版权所有
CuFeS2 is an eco-friendly n-type thermoelectric (TE) material but with poor performance. It is worth noting that the bandgap (E-g) reduction can enhance the carrier mobility (mu H) which further leads to a higher electrical conductivity (sigma) and power factor (PF). Density Functional Theory (DFT) calculation results indicated that Ag dopant in the CuFeS2 compound can narrow down the Eg. Hence, a series of Cu1-xAgxFeS2 (x=0-0.14) alloys were prepared by vacuum melting combined with plasma activated sintering to enhance the TE performance via a bandgap tuning route. It can be found that the Eg is indeed shrinking from similar to 0.45 to 0.39 eV with the increase of Ag dopant content, and the reduced Eg leads to an obviously enhanced mH without carrier concentration decreasing. Due to the elevated mH, a higher PF (0.76 x 10(-3) Wm(-1)K(-2)) can be obtained and a peak ZT value of 0.45 is achieved at 723 K in Cu0.88Ag0.12FeS2 sample. Therefore, the bandgap tuning can be regarded as an effective strategy for enhancing the TE performance of CuFeS2. (C) 2019 Elsevier B.V. All rights reserved.