Ultrahigh Thermoelectric Performance Realized in Black Phosphorus System by Favorable Band Engineering through Group VA Doping
Ultrahigh Thermoelectric Performance Realized in Black Phosphorus System by Favorable Band Engineering through Group VA Doping
复制标题
通过 VA 族掺杂的有利能带工程在黑磷系统中实现超高热电性能
DOI：
10.1002/adfm.201904346
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发表时间：
2019-07-19
影响因子：
19
通讯作者：
Liu, Xiaobing
中科院分区：
文献类型：
--
作者：
Duan, Shuai;Cui, Yangfan;Liu, Xiaobing
由于具有很强的电子和热各向异性，黑磷(BP)已经成为一种很有前途的热电候选材料，这表明可以通过控制潜在的高ZT的载流子输运方向来实现大的sigma/kappa比。然而，到目前为止，BP的转换效率低(ZT接近0.08,300K)和稳定性差仍然是阻碍其实际应用的主要问题。本文通过第一性原理计算，报道了具有高性能热电性能的简单组分XP7、XP3和Xp(X=N、As、Sb、Bi)的材料系列。在p型BiP7中，当电子浓度为3.67×10(19)cm(-3)时，最优载流子浓度为5.48×10(19)cm(-3)，当电子浓度为3.67×10(19)cm(-3)时，n型NP3中的ZT可达0.87，这是由于它们的态密度和费米能级附近的多谷能带结构通过VA客体原子和宿主原子的共振效应而增强的。此外，计算还表明，在800K时，原始BP在p型NP和n型NP3中的热电性能分别提高了约4.8倍和4.5倍。目前的研究结果表明，基于N-P系的热电材料具有较高的稳定性，在新型无金属、无毒、超轻热电材料方面具有广阔的应用前景。
Black phosphorus (BP) has emerged as a promising thermoelectric candidate because of its strong electronic and thermal anisotropy, suggesting a large sigma/kappa ratio can be realized by controlling carrier transport orientation for a potentially high ZT. Nevertheless, to date, low conversion efficiency (ZT approximate to 0.08, 300 K) and poor stability of BP remain the major issues that have hampered its practical applications. This work reports a material family in simple composition XP7, XP3, and XP (X = N, As, Sb, Bi) with high-performance thermoelectric properties by first-principles calculations. Strikingly, an ultrahigh ZT up to 1.21 at 300 K is achieved in p-type BiP7 with an optimal carrier concentration of 5.48 x 10(19) cm(-3) and ZT in n-type NP3 can reach up to approximate to 0.87 at the electron concentration of 3.67 x 10(19) cm(-3) along the zigzag direction, owing to their enhanced density of states and multivalley band structures around the Fermi level through the resonant effects of VA guest and host atoms. Additionally, the calculations demonstrate further improvement in thermoelectric performance of pristine BP by approximate to 4.8 and 4.5 times at 800 K in p-type NP and n-type NP3, respectively. Considering the high stability, current results indicate that N-P based systems are highly promising for novel metal-free, nontoxic, and ultralight thermoelectrics.