| 1. |
- Bhuyan, Prabal Dev, et al.
(författare)
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Ultrathin nanowire PdX2 (X = P, As) : stability, electronic transport and thermoelectric properties
- 2020
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 44:36, s. 15617-15624
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Tidskriftsartikel (refereegranskat)abstract
- In the last few decades, the miniaturization of devices has been taking place and therefore the quest for new nanowires has become more significant. In the present study, we have investigated the geometry of new ultrathin nanowires (NWs) of PdP2 and PdAs2 that could be obtained experimentally. We have optimized the pentagonal structures of both the NWs and studied their dynamical stability using the phonon dispersion curve. The electronic band structure shows semiconducting behaviour of PdP2 NWs with a band gap of 380 meV and PdAs2 NWs with a band gap of 294 meV, with higher charge carrier mobility than that of their 2D counterparts. The NWs show a band gap of 840 meV and 740 meV for PdP2 and PdAs2, respectively, through hybrid potential calculations. The PdX2 structure shows a transition from semiconducting to semi-metallic behaviour at a compressive strain of 8% within a sustainable pressure of 0.2–0.3 GPa. A negative differential conductance (NDC) effect is observed in the current–voltage graph for both the NWs. The semi-metallic behaviour with an asymmetric density of states near the Fermi energy boosts the Seebeck co-efficient value and therefore the ZTe value is enhanced for both the nanowires. The strained PdP2 and PdAs2 NWs show ZTe values of 4.75 and 5.49, respectively. Our study stimulates the feasibility of both nanowires and thermoelectric applications for the conversion of waste heat into electricity.
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| 2. |
- Hussain, T., et al.
(författare)
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Efficient and selective sensing of nitrogen-containing gases by Si2BN nanosheets under pristine and pre-oxidized conditions
- 2019
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Ingår i: Applied Surface Science. - : ELSEVIER SCIENCE BV. - 0169-4332 .- 1873-5584. ; 469, s. 775-780
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Tidskriftsartikel (refereegranskat)abstract
- Motivated by the promise of two-dimensional nanostructures in the field of gas sensing, we have employed van der Waals corrected density functional theory calculations to study the structural, electronic and gas sensing propensities of the recently designed Si2BN monolayer. Our rigorous simulations reveal that the representative members of nitrogen-containing gases (NCGs) such as NO, NO2 and NH3 binds extremely strongly on pristine Si2BN monolayer. However, a strong dissociative adsorption in case of NO and NO2 would poison the Si2BN and ultimately reversibility of the monolayer would be compromised. Exploring the sensing mechanism in more realistic pre-oxidized conditions, the binding characteristics of O-2@Si2BN changed dramatically, resulting into much lower adsorption in associative manner for all NO, NO2 and NH3. A visible change in work function indicates the variation in conductivity of O-2@Si2BN upon the exposure of incident gases. Sustainable values of binding energies would also ensure a quick recovery time that makes O-2@Si2BN an efficient nano sensor for pollutants like NCGs.
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| 3. |
- Jadav, Rahulkumar P., et al.
(författare)
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Structural Stability and Electronic Properties of 2D MXene Hf3C2F2 Monolayer by Density Functional Theory Approach
- 2023
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Ingår i: Biointerface Research in Applied Chemistry. - : AMG Transcend Association. - 2069-5837. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- The two-dimensional (2D) materials are highly demandable for the high charge rate in batteries. In Li-ion batteries, the 2D graphene materials are mostly well-studied. For metallic material, the physical/chemical properties can be tuned because the MXenes surface has a dangling bond according to their functional group, which provides MXenes are novel materials for batter electrochemical performance. The optimization and stability of the Hf3C2F2 monolayer are given ab-initio molecular dynamics (AIMD) by the density functional theory approach. Here, the monolayer of Hf3C2F2 has a stable structure, metallic nature, and low diffusion energy barrier shows a metal anode material for the rechargeable storage device.
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| 4. |
- Kansara, Shivam, et al.
(författare)
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Inquisitive Geometric Sites in h-BN Monolayer for Alkali Earth Metal Ion Batteries
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 123:32, s. 19340-19346
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical energy storage has been at the center of interest over the past years due to the ever-faster technological development and the need for high-capacity batteries with high voltages and energy densities. Alkali batteries show the greatest potential for improving current characteristics, and this work examines several hexagonal boron nitride configurations as electrodes for ion batteries. First-principles calculations based on density functional theory have been used to study structural, electronic, and electro-chemical properties of a graphenelike hexagonal boron nitride (h-BN) monolayer for various point defects. The maximum theoretical capacities for alkali earth metal ions adsorbed on the h-B9N8 monolayer are 762.264, 371.698, and 127.044 mAh/g, and average electrode potentials are 0.188, 0.009, and 5.735 V for the adsorption of Li+, Na+, and K+, respectively. Studied structures have been explored for the use as anode materials to hold alkali metal ions, namely, Li+, K+, and Na+, and we have found that for some cases, the alkali metal-h-BN structure shows metallic character, which leads to good electrical conductivity, without the change of structural geometry. Our results show that studied materials have characteristics suitable for the electrode-based ion batteries.
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| 5. |
- Kansara, Shivam, et al.
(författare)
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Theoretical Investigation of Metallic Nanolayers For Charge-Storage Applications
- 2018
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:7, s. 3428-3433
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Tidskriftsartikel (refereegranskat)abstract
- We report the first time that metallic homostructure of aluminene (Al) and antimonene (Sb) materials are the promising materials for the electric charge storage as a nanocapacitors. In this work, we have proposed two various phases of capacitor, namely, hexagonal (H) and trigonal (T) phases. Here, we have investigated the electronic properties, visualization of molecular orbitals, van der Waals (vdW) energy between layers, and supercapacitance properties, such as dipole moment (P), charge stored (Q(s)), energy stored (E-s), and capacitance (C). It is found that the Sb bilayer has higher capacitance values than Al bilayer. Instead of that, we have also focused on the various pristine homobilayer of boron (B), carbon (C), silicon (Si), phosphorus (P), gallium (Ga), germanium (Ge), arsenic (As), and indium (In) and heterobilayers of pristine C and Al, pristine C and Sb, pristine C and Si, pristine C and Sn, pristine C and As, and pristine P and Si for H and T phases, respectively, and results are compared with Al and Sb. Our investigated energy storage, charge, and capacitance values are in better agreement with the previously reported works. The capacitance value increased accordingly to the external electric field and behave as an ideal nanocapacitor. The results suggest that Al- and Sb-homobilayer could be flexible method for building nanoscale capacitors and nanocircuits.
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| 6. |
- Kumavat, Sandip R., et al.
(författare)
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Two-Dimensional CH3NH3PbI3 with High Efficiency and Superior Carrier Mobility : A Theoretical Study
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:9, s. 5231-5239
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) halide perovskites have distinct tunable compositional and structural properties, which make 2D materials a good candidate to improve the characteristics of photovoltaic applications. We have explored strain-dependent structural, electronic, and optical properties of organic inorganic hybrid perovskite CH3NH3PbI3 monolayers using density functional calculations. Here, we have calculated carrier mobility of electrons and holes and the band gap of the CH3NH3PbI3 monolayer. The results suggest that with increasing tensile and compressive strains, the band gap increases up to 5% (in the case of tensile strain), whereas decreases toward instability, i.e., 9% (in the case of compressive strain). The carrier mobility of 2D CH3NH3PbI3 is approximately 16 times larger than that of the bulk form of CH3NH3PbI3. Furthermore, we have also investigated optical properties, which show good activity in the visible as well as in the high-ultraviolet region of the spectrum. In addition, the 2D CH3NH3PbI3 monolayer shows good transmittance (>80%) in a lower energy range as well as high absorption coefficient of 14.09 X 10(5) cm(-1) at 8.8 eV, which is up to 40% higher than that of the bulk form of CH3NH3PbI3; however, under both types of strains, the absorption coefficient is decreased in the 2D CH3NH3PbI3 monolayer. For photovoltaic applications, we have calculated the open-circuit voltage (V-oc), fill factor (FF), short-circuit current density (J(sc)), and power conversion efficiency (eta) of the 2D CH3NH3PbI3 monolayer. Our theoretical results suggest that the power conversion efficiency (eta) is 28%, which is higher than that of its bulk form and 5% less than the Shockley-Queisser limit (33%), suggesting that 2D CH3NH3PbI3 is a good candidate for the solar cell application.
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| 7. |
- Lakhani, Krupa, et al.
(författare)
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Dissociation of air pollutants on the uniform surface of pentagonal BeP2
- 2021
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 570
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Tidskriftsartikel (refereegranskat)abstract
- In this present work, the investigation was carried out using density functional theory (DFT) for the dissociation of noxious gas molecules such as carbon and nitrogen-based molecules (CO, CO2, N-2, NH3, NO, and NO2) on a pentagonal two-dimensional beryllium diphosphide (BeP2). The pentagonal BeP2 monolayer has a similar band structure as graphene. Here, some carbon and nitrogen-based noxious gases such as CO, CO2, N-2, NH3, NO, and NO2 with Van der Waals (vdW) interaction behave like physisorbed, while strong covalent (Be-O) interactions of O-2 on BeP2 formed chemisorption. Due to the chemisorption of O-2 gas molecules, the bandgap at Dirac point at P-site on BeP2 opens. While CO, CO2, N-2, NO, and NO2 are dissociated at the C-site, only CO, N-2, and NO are dissociated at the P-site. Beryllium diphosphide's band-gap shifts resulting from interactions with CO, N-2, and O-2 molecules are just 6%, 12.1%, and 22.2%, respectively, meaning that the BeP2 material has a moderate and high sensitivity towards CO, N-2, and O-2 molecules. BeP2 appears to be a potential catalyst for the dissociation of CO, CO2, N-2, NO, NO2, and O-2 gas molecules, which is even more interesting.
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| 8. |
- Mahida, Hardipinh, et al.
(författare)
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Exploring the Potential of Substituted and Defected Magnesium Dichloride Monolayers for Optoelectronic Applications
- 2024
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Ingår i: ACS APPLIED ELECTRONIC MATERIALS. - : American Chemical Society (ACS). - 2637-6113. ; 6:1, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the effects of vacancy defects and substitutional doping on the structural, electronic, and linear optical characteristics of the magnesium dichloride (MgCl2) monolayer are investigated using density functional theory. The GGA-PBE functional is used to derive optical characteristics such as real and imaginary parts of the dielectric function, absorption coefficient, extinction coefficient, refractive index, reflectivity, and electron energy loss function. The results reveal that creating a Cl atom vacancy inside the MgCl2 monolayer is energetically favorable, and the study provides insights into how vacancy defects and substitutional doping can be utilized to modulate the electronic and optical properties of the MgCl2 monolayer for potential applications in optoelectronics. The outcomes of this research can potentially lead to the growth of more efficient and effective optoelectronic devices.
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| 9. |
- Mahida, H. R., et al.
(författare)
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2D MgF2 nanosheet as a promising candidate for thermoelectric material
- 2021
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Ingår i: Materials today. - : Elsevier. - 2214-7853. ; , s. 555-558
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Konferensbidrag (refereegranskat)abstract
- The electronic and thermoelectric (TE) characteristics of MgF2 monolayer theoretically simulated by merging first-principles calculations with Boltzmann semi-classical approach. We have studied the thermopower, electrical conductivity, thermal conductivity, power factor (PF), and figure of merit (ZT) utilizingBoltzTraP code. Due to the ultralow thermal conductivity of T-phase of MgF2, monolayer is beneficial for superior TE materials. The maximum ZT values are of 0.93 at lower temperature and 0.70 at 800 K for T-phase of MgF2 monolayer. These theoretical investigations suggest that these materials have potential applications in better performance for thermoelectric (TE) devices at the room, as well as higher temperatures.
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| 10. |
- Mahida, H. R., et al.
(författare)
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Electronic and optical properties of a structural defect in 2D MgF2 monolayer
- 2020
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Ingår i: 3rd international conference on condensed matter & applied physics (ICC-2019). - : AIP Publishing. - 9780735419766
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Konferensbidrag (refereegranskat)abstract
- In this paper, we have studied structural and optoelectronic properties of 2D pristine MgF2 monolayer and create the F atom vacancy inside the system. The electronic density of states showed transition from insulator to semiconducting behavior by structural defect induced and corresponding band gaps are 2.98 eV and 2.00 eV for H-phase and T-phase, respectively were obtained, which was computed by using GGA-PBE functional. With the structural defect in MgF2 system showed the strong hybridization of Mg s-orbital and F p-orbital in the occupied orbital in the valence and conduction band range.. The optical properties were calculated by RPA quasi particles with single-shot GW0 approach. From the imaginary part of dielectric function, it absorbs only Ultraviolet (UV) light. These theoretical investigations suggest that the pristine and defected MgF2 monolayer system may serve as a superior candidate for UV light absorbing nanodevices.
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