The effective mass, fitness function and enhanced thermoelectric properties in CuSbS2 for p-type thermoelectric material applications: Density functional theory approach

2021 ◽  
Vol 273 ◽  
pp. 115404
Author(s):  
Timothy M. Ashani ◽  
Paul O. Adebambo ◽  
Funmilayo Ayedun ◽  
Idowu O. Osinuga ◽  
Mopelola A. Idowu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Effective Mass ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Density Functional ◽  
Fitness Function ◽  
Theory Approach ◽  
Functional Theory ◽  
P Type

scholarly journals Enhanced mechanism of thermoelectric performance of Bi2Se3 using density functional theory

2020 ◽  
Vol 9 (3) ◽  
Author(s):  
Muhammad Zamir Mohyedin ◽  
Mohamad Fariz Mohamad Taib ◽  
Afiq Radzwan ◽  
M. Mustaffa ◽  
Amiruddin Shaari ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Effective Mass ◽  
Thermoelectric Properties ◽  
Density Of States ◽  
Power Factor ◽  
Figure Of Merit ◽  
Density Functional ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
Functional Theory

Abstract Good thermoelectric performance is being sought to face major problems related to energy, especially in the concern of the usage of energy on environmental impact. In this work, we investigate the underlying mechanism to enhance the thermoelectric performance of bismuth selenide (Bi2Se3) by employing density functional theory (DFT) followed by the Boltzmann transport equation under relaxation time approximation. The structural, electronic, and thermoelectric properties were calculated and analyzed. From the analysis of combined results of thermoelectric properties and electronic properties as the function of the Fermi level, we found that the power factor of Bi2Se3 is improved by increasing electrical conductivity that contributed by the large density of states and light effective mass of charge carriers. The figure of merit, on the other hand, is enhanced by increasing Seebeck coefficient that contributed by heavy effective mass and decreasing thermal conductivity that contributed by low density of states. We also found that both power factor and figure of merit can be improved through n-type doping at 300 K and p-type doping at higher temperature (400 K and 500 K).

Electronic Structures and Thermoelectric Properties of NaCo2O4 Thermoelectric Material

2011 ◽  
Vol 317-319 ◽  
pp. 2051-2055 ◽  
Author(s):  
Qiu Hua Ma ◽  
Qing Wei Wang ◽  
Peng Xian Lu ◽  
Yong Gai Hou
Keyword(s):  
Electrical Conductivity ◽  
Effective Mass ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Covalent Bond ◽  
Strongly Correlated ◽  
Functional Theory

The electronic structures of thermoelectric material NaCo2O4 were studied by the first-principles calculations with plane-wave pseudopotential method and generalized approximation (GGA) based on density functional theory (DFT). On the basis of calculation for electronic structures, thermoelectric properties of NaCo2O4 were also investigated in this paper. The reasons for large thermoelectric potential are large effective mass of holes at the top of valence band and 6μB net spin magnetic moment. While high electrical conductivity should be attributed to small effective mass of electrons at the bottom of conduction band, large carrier concentration near the Fermi level and narrowed energy gap. In addition, covalent bond between Co atom and O atom promotes carrier mobility and thus benefits to electrical conductivity. Na1 and Na2 have different effects on the NaCo2O4. Na1 provides local state electrons and yet Na2 provides itinerant-electrons which play important role to strongly correlated system.

scholarly journals Tunable Electronic Properties of Nitrogen and Sulfur Doped Graphene: Density Functional Theory Approach

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 268 ◽  
Author(s):  
Ji Lee ◽  
Sung Kwon ◽  
Soonchul Kwon ◽  
Min Cho ◽  
Kwang Kim ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Fermi Level ◽  
Electronic Properties ◽  
Density Functional ◽  
Pristine Graphene ◽  
Theory Approach ◽  
Functional Theory ◽  
Doped Graphene ◽  
P Type

We calculated the band structures of a variety of N- and S-doped graphenes in order to understand the effects of the N and S dopants on the graphene electronic structure using density functional theory (DFT). Band-structure analysis revealed energy band upshifting above the Fermi level compared to pristine graphene following doping with three nitrogen atoms around a mono-vacancy defect, which corresponds to p-type nature. On the other hand, the energy bands were increasingly shifted downward below the Fermi level with increasing numbers of S atoms in N/S-co-doped graphene, which results in n-type behavior. Hence, modulating the structure of graphene through N- and S-doping schemes results in the switching of “p-type” to “n-type” behavior with increasing S concentration. Mulliken population analysis indicates that the N atom doped near a mono-vacancy is negatively charged due to its higher electronegativity compared to C, whereas the S atom doped near a mono-vacancy is positively charged due to its similar electronegativity to C and its additional valence electrons. As a result, doping with N and S significantly influences the unique electronic properties of graphene. Due to their tunable band-structure properties, the resulting N- and S-doped graphenes can be used in energy and electronic-device applications. In conclusion, we expect that doping with N and S will lead to new pathways for tailoring and enhancing the electronic properties of graphene at the atomic level.

scholarly journals Investigation of Thermal Properties of Half-Heusler Alloy FeVZ (Z= As, P, Sb) within Density Functioal Theory

2021 ◽  
Vol 4 (1) ◽  
pp. 45-51
Author(s):  
Anugrah Azhar
Keyword(s):  
Density Functional Theory ◽  
Thermal Properties ◽  
Thermoelectric Material ◽  
Temperature Regime ◽  
Heusler Alloy ◽  
Potential Application ◽  
Figure Of Merit ◽  
Density Functional ◽  
Functional Theory ◽  
P Type

The figure of merit (ZT) holds an important role in thermoelectric material that indicates the efficiency of thermoelectric (TE) devices. The higher ZT value, the higher efficiency would be obtained of TE devices. One of the sub-class materials that has high potential application for thermoelectric material is half-Heusler (HH) alloy. In order to investigate the ZT value of HH conduct simulation using to investigate the ZT value of HH alloy FeVZ (Z= As, P, Sb) by using density-functional theory (DFT). Our research results show that FeVAs has higher ZT values than FeVP and FeVSb in the range temperature of 150-900 K. All of those compounds still have good ZT value around ~0.7 even in the temperature regime of 900 K, and shows a good trend for p-type thermoelectric materials.

scholarly journals Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdur Rauf ◽  
Muhammad Adil ◽  
Shabeer Ahmad Mian ◽  
Gul Rahman ◽  
Ejaz Ahmed ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Optical Absorption ◽  
Water Splitting ◽  
Density Functional ◽  
Formation Energy ◽  
Visible Region ◽  
Photoelectrochemical Water Splitting ◽  
Theory Approach ◽  
Functional Theory

AbstractHematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

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