scholarly journals Biaxial Tensile Strain-Induced Enhancement of Thermoelectric Efficiency of α-Phase Se2Te and SeTe2 Monolayers

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Shao-Bo Chen ◽  
Gang Liu ◽  
Wan-Jun Yan ◽  
Cui-E Hu ◽  
Xiang-Rong Chen ◽  
...  

Thermoelectric (TE) materials can convert waste heat into electrical energy, which has attracted great interest in recent years. In this paper, the effect of biaxial-tensile strain on the electronic properties, lattice thermal conductivity, and thermoelectric performance of α-phase Se2Te and SeTe2 monolayers are calculated based on density-functional theory and the semiclassical Boltzmann theory. The calculated results show that the tensile strain reduces the bandgap because the bond length between atoms enlarges. Moreover, the tensile strain strengthens the scatting rate while it weakens the group velocity and softens the phonon model, leading to lower lattice thermal conductivity kl. Simultaneously, combined with the weakened kl, the tensile strain can also effectively modulate the electronic transport coefficients, such as the electronic conductivity, Seebeck coefficient, and electronic thermal conductivity, to greatly enhance the ZT value. In particular, the maximum n-type doping ZT under 1% and 3% strain increases up to six and five times higher than the corresponding ZT without strain for the Se2Te and SeTe2 monolayers, respectively. Our calculations indicated that the tensile strain can effectively enhance the thermoelectric efficiency of Se2Te and SeTe2 monolayers and they have great potential as TE materials.

2018 ◽  
Vol 20 (43) ◽  
pp. 27611-27620 ◽  
Author(s):  
Armin Taheri ◽  
Carlos Da Silva ◽  
Cristina H. Amon

A first-principles study is conducted to investigate the effect of biaxial tensile strain on phonon properties and thermal conductivity of buckled phosphorene and arsenene, novel two-dimensional (2D) materials of group-VA.


2016 ◽  
Vol 4 (20) ◽  
pp. 4538-4545 ◽  
Author(s):  
H. Y. Lv ◽  
W. J. Lu ◽  
D. F. Shao ◽  
H. Y. Lu ◽  
Y. P. Sun

The thermoelectric performance of the ZrS2monolayer is greatly enhanced by the biaxial tensile strain, due to the simultaneous increase of the Seebeck coefficient and decrease of the thermal conductivity.


2013 ◽  
Vol 27 (25) ◽  
pp. 1350138 ◽  
Author(s):  
Q. YANG ◽  
H. LIAO ◽  
J. X. CAO ◽  
Y. MA ◽  
Y. C. ZHOU

Spontaneous polarization and its strain effects of bismuth titanate (BiT) with B2cb and B1a1 space groups are studied by first-principles density functional theory (DFT) calculation. B1a1 was proved to be the most stable phase structure and the spontaneous polarization is in good agreement with the experimental value. Similar variations of the principal polarization component (Pa) are obtained for B2cb and B1a1 structured BiT by applying b-uniaxial, c-uniaxial, ab-biaxial and bc-biaxial strains. It is found that the Pa is enhanced about 18.5% (20.8%) with ab-biaxial tensile strain of 2.4% for B2cb(B1a1) structure. Polarization along the c-axis (Pc) for the B1a1 structure is improved by 59.1% when bc-biaxial tensile strain reaches 2.4%.


MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3637-3643
Author(s):  
William T. Yorgason ◽  
Arden N. Barnes ◽  
Nick Roberts

ABSTRACT Thermoelectric materials have been of interest for several decades due to their ability to recapture waste heat of various systems and convert it to useful electricity. One method used to improve the thermoelectric efficiency of a material is to reduce the lattice thermal conductivity (k p ) while not affecting the other properties. In order to reduce the k p of the material, this paper introduces silicon (Si) nanoparticles (NPs) in Mg2Si to manipulate phonon scattering and mean free path. A series of simulations is performed with the metal silicide thermoelectric material MgxSix. The objective of this work is two-fold: 1) to determine the optimal Si nanoparticle (NP) concentration and 2) to determine the optimal MgxSix stoichiometry for minimizing the k p of the system. It should be noted, however, that the assumed reduction in thermal conductivity is only a result of reduced phonon transport and that minimal impact is made on the transport of electrons. Interestingly, the uniform off-stoichiometry (49.55 atomic percent (a/o) Si) sample of MgxSix resulted in a reduction of k p of 84.62 %, while the Si NP sample, with matching a/o Si, resulted in a reduction of k p of 78.82 %.


2021 ◽  
Vol 130 (4) ◽  
pp. 045101
Author(s):  
Qi Zhong ◽  
Zhenhong Dai ◽  
Junping Wang ◽  
Yinchang Zhao ◽  
Sheng Meng

Author(s):  
Jonathan Skelton

Thermoelectric generators (TEGs) convert waste heat to electricity and are a leading contender for improving energy efficiency at a range of scales. Ideal TE materials show a large Seebeck effect,...


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Hu ◽  
Yue-Wen Fang ◽  
Feiyu Qin ◽  
Xun Cao ◽  
Xiaoxu Zhao ◽  
...  

AbstractThermoelectrics enable waste heat recovery, holding promises in relieving energy and environmental crisis. Lillianite materials have been long-term ignored due to low thermoelectric efficiency. Herein we report the discovery of superior thermoelectric performance in Pb7Bi4Se13 based lillianites, with a peak figure of merit, zT of 1.35 at 800 K and a high average zT of 0.92 (450–800 K). A unique quality factor is established to predict and evaluate thermoelectric performances. It considers both band nonparabolicity and band gaps, commonly negligible in conventional quality factors. Such appealing performance is attributed to the convergence of effectively nested conduction bands, providing a high number of valley degeneracy, and a low thermal conductivity, stemming from large lattice anharmonicity, low-frequency localized Einstein modes and the coexistence of high-density moiré fringes and nanoscale defects. This work rekindles the vision that Pb7Bi4Se13 based lillianites are promising candidates for highly efficient thermoelectric energy conversion.


2021 ◽  
Vol 197 ◽  
pp. 110644
Author(s):  
Juan Song ◽  
Zhao Ding ◽  
Xue-Fei Liu ◽  
Ze-Chen Huang ◽  
Jia-Wei Li ◽  
...  

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