Exploring the possibility of enhancing the figure-of-merit (&gt; 2) of Na0.74CoO2: A combined experimental and theoretical study

Sk, Shamim; Pati, Jayashree; Dhaka, R. S.; Pandey, Sudhir K.

doi:10.1140/epjb/e2020-10227-x

Cited by 7 publications

(5 citation statements)

References 52 publications

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“…For this semiconducting material, we used the constant electron relaxation time τ values of 1 × 10 −14 s (τ 1 ) and It is preferable to calculate the conversion % efficiency (η) of TE material once the ZT is known. Here, the segmentation method has been considered for estimating the η [54,70,71]. Figure 11(b) shows the calculated maximum possible η for n-type and p-type compounds using τ 1 and τ 2 .…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

Solet¹,

Sk²,

Pandey³

2022

Phys. Scr.

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In this paper, we have presented a theoretical study in the context of photovoltaic (PV) and thermoelectric (TE) applications of ScAgC. The electronic, optical, and thermoelectric properties have been investigated systematically using DFT and semi-classical Boltzmann transport theory. DFT calculates a direct band-gap of ∼0.47 eV, whereas the G0W0 method estimates a band-gap of ∼1.01 eV. We used parabola fitting to estimate the effective mass (m*) values for bands B1–B4 at Γ-point, which are ∼ -0.087 (-0.075), ∼ -0.17 (-0.27), ∼ -0.17 (-0.27), and ∼ 0.049 (0.058) along the Γ-X (Γ-L) direction, respectively. We have investigated phonon dispersion and thermal properties. Furthermore, the properties of optoelectronics are calculated and analysed over a range of photon energies from 0 to 10 eV. The optical conductivity σ(ω), refractive index ñ(ω), and dielectric function ε(ω) show strong optical transitions in the visible region. The lowest calculated value of reflectivity r(ω) is ∼0.24 at ∼4.7 eV, and the highest calculated value of absorption coefficient α(ω) is ∼1.7×106 cm-1 at ∼8.5 eV. At 300 K, we have expected a maximum solar efficiency (SLME) of ∼33% at ∼1 µm of thickness. The lattice part of thermal conductivity κph shows a maximum value of ∼3.8 Wm-1K-1 at 1200 K. At 1200 K, for electron doping of ∼3.9×1021 cm-3, the maximum value of S2σ/τ is ∼145×1014 µWK-2cm-1s-1, while for hole doping of ∼1.5×1021 cm-3, it is ∼123×1014 µWK-2cm-1s-1. The highest ZT at 1200 K is expected to be ∼0.53, whereas the optimal %efficiency is predicted to be ∼8.5% for cold and hot temperatures of 300 K and 1200 K, respectively. The collected results suggest that the ScAgC compound would be a potential candidate for renewable energy sources such as solar cell and TE applications.

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Section: Thermoelectric Propertiesmentioning

confidence: 99%

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

Solet¹,

Sk²,

Pandey³

2022

Phys. Scr.

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“…Studying the properties of strongly correlated electron systems (SCES) have been attracted much attention of scientific community from last few decades as they show unusual properties such as metal-insulator (MI) transition, half-metallicity, S, σ, high temperature superconductivity, colossal magnetoresistance etc [15][16][17][18]. In the search of TE materials for high temperature application, SCES were found more suitable candidates in TE field [19][20][21][22]. Correlation effects in SCES were shown to enhance the S [19][20][21][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…The spin and orbital degrees of freedom have been found to play an important role for large values of S in this system [26][27][28]. The experimental and theoretical studies of S on SCES have been carried out by many groups [19][20][21][22][29][30][31][32][33][34]. LaNiO 3 is a strongly correlated transition metal oxide, which comes under rare earth nickelates (RNiO 3 , R = rare earth) group.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Seebeck coefficient of LaNiO₃ compound in the temperature range 300–620 K

Khatun¹,

Sk²,

Pandey³

2022

J. Phys.: Condens. Matter

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Transition metal oxides have been attracted much attention in thermoelectric community from the last few decades. In the present work, we have synthesized LaNiO3 by a simple solution combustion process. To analyze the crystal structure and structural parameters we have used Rietveld reﬁnement method wherein FullProf software is employed. The room temperature x-ray diffraction indicates the rhombohedral structure with space group R 3 c (No. 167). The refined values of lattice parameters are a = b = c = 5.4071 Å. Temperature dependent Seebeck coeﬃcient (S) of this compound has been investigated by using experimental and computational tools. The measurement of S is conducted in the temperature range 300-620 K. The measured values of S in the entire temperature range have negative sign that indicates n-type character of the compound. The value of S is found to be ∼ -8 µV/K at 300 K and at 620 K this value is ∼ -12 µV/K. The electronic structure calculation is carried out using DFT+U method due to having strong correlation in LaNiO3. The calculation predicts the metallic ground state of the compound. Temperature dependent S is calculated using BoltzTraP package and compared with experiment. The best matching between experimental and calculated values of S is observed when self-interaction correction is employed as double counting correction in spin-polarized DFT + U (= 1 eV) calculation. Based on the computational results maximum power factors are also calculated for p-type and n-type doping of this compound.

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“…Studying the properties of strongly correlated electron systems (SCES) have been attracted much attention of scientific community from last few decades as they show unusual properties such as metal-insulator (MI) transition, half-metallicity, S, σ, high temperature superconductivity, colossal magnetoresistance etc [16][17][18][19] . In the search of TE materials for high temperature application, SCES were found more suitable candidates in TE field [20][21][22][23] . Correlation effects in SCES were shown to enhance the S [20][21][22][24][25][26] .…”

Section: Introductionmentioning

confidence: 99%

“…The spin and orbital degrees of freedom have been found to play an important role for large values of S in this system [27][28][29] . The experimental and theoretical studies of S on SCES have been carried out by many groups [20][21][22][23][30][31][32][33][34][35] . LaNiO 3 is a strongly correlated transition metal oxide, which comes under rare earth nickelates (RNiO 3 , R = rare earth) group.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Seebeck coefficient of LaNiO3 compound in the temperature range 300-620 K

Khatun,

Sk,

Pandey

2021

Preprint

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Transition metal oxides have been attracted much attention in thermoelectric community from the last few decades. In the present work, we have synthesized LaNiO3 by a simple solution combustion process. To analyze the crystal structure and structural parameters we have used Rietveld refinement method wherein FullProf software is employed. The room temperature x-ray diffraction indicates the trigonal structure with space group R 3 c (No. 167). The refined values of lattice parameters are a = b = 5.4615 Å & c = 13.1777 Å. Temperature dependent Seebeck coefficient (S) of this compound has been investigated by using experimental and computational tools. The measurement of S is conducted in the temperature range 300−620 K. The measured values of S in the entire temperature range have negative sign that indicates n-type character of the compound. The value of S is found to be ∼ −8 µV/K at 300 K and at 620 K this value is ∼ −12 µV/K. The electronic structure calculation is carried out using DFT+U method due to having strong correlation in LaNiO3. The calculation predicts the metallic ground state of the compound. Temperature dependent S is calculated using BoltzTraP package and compared with experiment. The best matching between experimental and calculated values of S is observed when self-interaction correction is employed as double counting correction in spin-polarized DFT + U (= 1 eV) calculation. Based on the computational results maximum power factors are also calculated for p-type and n-type doping of this compound.

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Exploring the possibility of enhancing the figure-of-merit (> 2) of Na0.74CoO2: A combined experimental and theoretical study

Cited by 7 publications

References 52 publications

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

Understanding the Seebeck coefficient of LaNiO₃ compound in the temperature range 300–620 K

Understanding the Seebeck coefficient of LaNiO3 compound in the temperature range 300-620 K

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Exploring the possibility of enhancing the figure-of-merit (> 2) of Na0.74CoO2: A combined experimental and theoretical study

Cited by 7 publications

References 52 publications

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

First-principles study of optoelectronic and thermoelectronic properties of the ScAgC half-Heusler compound

Understanding the Seebeck coefficient of LaNiO3 compound in the temperature range 300–620 K

Understanding the Seebeck coefficient of LaNiO3 compound in the temperature range 300-620 K

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Understanding the Seebeck coefficient of LaNiO₃ compound in the temperature range 300–620 K