Enhanced thermoelectric performance of defect engineered monolayer graphene

2022 ◽  
Author(s):  
Woochang Kim ◽  
Wonseok Lee ◽  
Seung-Mo Lee ◽  
Duckjong Kim ◽  
Jinsung Park

Abstract We propose a method of improving the thermoelectric properties of graphene using defect engineering through plasma irradiation and atomic layer deposition (ALD). We intentionally created atomic blemishes in graphene by oxygen plasma treatment and subsequently healed the atomistically defective places using Pt-ALD. After healing, the thermal conductivity of the initially defective graphene increased slightly, while the electrical conductivity and the square of the Seebeck coefficient increased pronouncedly. The thermoelectric figure of merit of the Pt-ALD treated graphene was measured to be over 4.8 times higher than the values reported in the literature. We expect that our study could provide a useful guideline for the development of graphene-based thermoelectric devices.

2021 ◽  
Vol 9 ◽  
Author(s):  
Fuming Zhang ◽  
Guanghui Song ◽  
Dayakar Gandla ◽  
Yair Ein-Eli ◽  
Daniel Q. Tan

As a conventional electrode material of electric double-layer capacitors (EDLC), activated carbon (AC) still faces challenges to exhibit high capacitance. To address this problem, herein, we introduce a combined method of oxygen plasma and Al2O3 tomic layer deposition (ALD) on AC electrodes to reduce the impedance and improve the cycle stability of EDLC. The defect structure can be precisely designed by simply tuning the oxygen-plasma treatment time, thereby affecting the microstructures of AC electrode. Such a tactic permits the first-operated AC electrode with more defects and the ALD passivation of AC resulting in an outstanding rate performance for the device (40.6 F g–1 at 5 mA cm–2, 20.1 Fg–1 at 100 mA cm–2) and cycling stability (∼90% retention after 5,000 cycles). This benefit from the synergistic effect of defects from doped oxygen and stable aluminum oxide layer on the electrode surface. This work delivers a feasible strategy to construct a stable AC material with superior cycling performance for supercapacitor.


2015 ◽  
Vol 6 ◽  
pp. 1176-1182 ◽  
Author(s):  
Hatef Sadeghi ◽  
Sara Sangtarash ◽  
Colin J Lambert

We demonstrate that thermoelectric properties of graphene nanoribbons can be dramatically improved by introducing nanopores. In monolayer graphene, this increases the electronic thermoelectric figure of merit ZT e from 0.01 to 0.5. The largest values of ZT e are found when a nanopore is introduced into bilayer graphene, such that the current flows from one layer to the other via the inner surface of the pore, for which values as high as ZT e = 2.45 are obtained. All thermoelectric properties can be further enhanced by tuning the Fermi energy of the leads.


Author(s):  
Enamul Haque

This article reports the extraordinary thermoelectric figure of merit (ZT) of NaBaBi: degenerate bands, instead of the valley degeneracy of Bi2Te3, highly non-parabolic bands, and low DOS near the Fermi level of NaBaBi lead to an extraordinary ZTisotropic ≈ 1.60 at 350 K.


2019 ◽  
Vol 34 (02) ◽  
pp. 2050019 ◽  
Author(s):  
Y. Zhang ◽  
M. M. Fan ◽  
C. C. Ruan ◽  
Y. W. Zhang ◽  
X.-J. Li ◽  
...  

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.


2020 ◽  
Vol 22 (4) ◽  
pp. 2081-2086 ◽  
Author(s):  
Taiki Tanishita ◽  
Koichiro Suekuni ◽  
Hirotaka Nishiate ◽  
Chul-Ho Lee ◽  
Michitaka Ohtaki

Co-substitution of Ge and P for Sb in Cu3SbS4 famatinite boosted dimensionless thermoelectric figure of merit.


2007 ◽  
Vol 534-536 ◽  
pp. 161-164 ◽  
Author(s):  
Taek Soo Kim ◽  
Byong Sun Chun

N-type Bi2Te3-Sb2Te3 solid solutions doped with CdCl2 was prepared by melt spinning, crushing and vacuum sintering processes. Microstructure, bending strength and thermoelectric property were investigated as a function of the doping quantity from 0.03wt.% to 0.10wt.% and sintering temperature from 400oC to 500oC, and finally compared with those of conventionally fabricated alloys. The alloy showed a good structural homogeneity as well as bending strength of 3.88Kgf/mm2. The highest thermoelectric figure of merit was obtained by doping 0.03wt.% and sintering at 500oC.


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