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Mohebbi E, Pavoni E, Pierantoni L, Stipa P, Hemmetter A, Laudadio E, Mencarelli D. Towards graphene-based asymmetric diodes: a density functional tight-binding study. NANOSCALE ADVANCES 2024; 6:1548-1555. [PMID: 38419871 PMCID: PMC10898435 DOI: 10.1039/d3na00603d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 02/02/2024] [Indexed: 03/02/2024]
Abstract
Self-consistent charge density functional tight-binding (DFTB) calculations have been performed to investigate the electrical properties and transport behavior of asymmetric graphene devices (AGDs). Three different nanodevices constructed of different necks of 8 nm, 6 nm and 4 nm, named Graphene-N8, Graphene-N6 and Graphene-N4, respectively, have been proposed. All devices have been tested under two conditions of zero gate voltage and an applied gate voltage of +20 V using a dielectric medium of 3.9 epsilon interposed between the graphene and the metallic gate. As expected, the results of AGD diodes exhibited strong asymmetric I(V) characteristic curves in good agreement with the available experimental data. Our predictions implied that Graphene-N4 would achieve great asymmetry (A) of 1.40 at |VDS| = 0.2 V with maximum transmittance (T) of 6.72 in the energy range 1.30 eV. More importantly, while the A of Graphene-N4 was slightly changed by applying the gate voltage, Graphene-N6/Graphene-N8 showed a significant effect with their A increased from 1.20/1.03 under no gate voltage (NGV) to 1.30/1.16 under gate voltage (WGV) conditions. Our results open up unprecedented numerical prospects for designing tailored geometric diodes.
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Affiliation(s)
- Elaheh Mohebbi
- Department of Science and Engineering of Matter, Environment and Urban Planning (SIMAU), Marche Polytechnic University 60131 Ancona Italy
| | - Eleonora Pavoni
- Department of Science and Engineering of Matter, Environment and Urban Planning (SIMAU), Marche Polytechnic University 60131 Ancona Italy
| | - Luca Pierantoni
- Information Engineering Department, Marche Polytechnic University 60131 Ancona Italy
| | - Pierluigi Stipa
- Department of Science and Engineering of Matter, Environment and Urban Planning (SIMAU), Marche Polytechnic University 60131 Ancona Italy
| | - Andreas Hemmetter
- Advanced Microelectronic Center Aachen (AMICA), AMO GmbH 52074 Aachen Germany
| | - Emiliano Laudadio
- Department of Science and Engineering of Matter, Environment and Urban Planning (SIMAU), Marche Polytechnic University 60131 Ancona Italy
| | - Davide Mencarelli
- Information Engineering Department, Marche Polytechnic University 60131 Ancona Italy
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Khanyile BS, Numan N, Simo A, Nkosi M, Mtshali CB, Khumalo Z, Madiba IG, Mabakachaba B, Swart H, Coetsee-Hugo E, Duvenhage MM, Lee E, Henini M, Gibaud A, Chaker M, Rezaee P, Lethole N, Akbari M, Morad R, Maaza M. Towards Room Temperature Thermochromic Coatings with controllable NIR-IR modulation for solar heat management & smart windows applications. Sci Rep 2024; 14:2818. [PMID: 38307893 PMCID: PMC10837131 DOI: 10.1038/s41598-024-52021-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 01/12/2024] [Indexed: 02/04/2024] Open
Abstract
Solar heat management & green air-conditioning are among the major technologies that could mitigate heat islands phenomenon while minimizing significantly the CO2 global foot-print within the building & automotive sectors. Chromogenic materials in general, and thermochromic smart coatings especially are promising candidates that consent a noteworthy dynamic solar radiation Infrared (NIR-IR) regulation and hence an efficient solar heat management especially with the expected increase of the global seasonal temperature. Within this contribution, two major challenging bottlenecks in vanadium oxide based smart coatings were addressed. It is validated for the first time that the NIR-IR modulation of the optical transmission (∆TTRANS = T(T〈TMIT) - T(T〉TMIT) of Vanadium oxide based smart coatings can be controlled & tuned. This upmost challenging bottle-neck controllability/tunability is confirmed via a genuine approach alongside to a simultaneous drastic reduction of the phase transition temperature TMIT from 68.8 °C to nearly room temperature. More precisely, a substantial thermochromism in multilayered V2O5/V/V2O5 stacks equivalent to that of standard pure VO2 thin films but with a far lower transition temperature, is reported. Such a multilayered V2O5/V/V2O5 thermochromic system exhibited a net control & tunability of the optical transmission modulation in the NIR-IR (∆TTRANS) via the nano-scaled thickness' control of the intermediate Vanadium layer. In addition, the control of ∆TTRANS is accompanied by a tremendous diminution of the thermochromic transition temperature from the elevated bulk value of 68.8 °C to the range of 27.5-37.5 ºC. The observed remarkable and reversible thermochromism in such multilayered nano-scaled system of V2O5/V/V2O5 is likely to be ascribed to a noteworthy interfacial diffusion, and an indirect doping by alkaline ions diffusing from the borosilicate substrate. It is hoped that the current findings would contribute in advancing thermochromic smart window technology and their applications for solar heat management in glass windows in general, skyscraper especially & in the automotive industry. If so, this would open a path to a sustainable green air-conditioning with zero-energy input.
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Affiliation(s)
- B S Khanyile
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa.
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa.
| | - N Numan
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - A Simo
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - M Nkosi
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - C B Mtshali
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
| | - Z Khumalo
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
| | - I G Madiba
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - B Mabakachaba
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
- Physics Department, University of the Western Cape, P.O. Box 1906, Bellville, 7535, South Africa
| | - H Swart
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - E Coetsee-Hugo
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - Mart-Mari Duvenhage
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - E Lee
- Faculty of Natural and Agricultural Sciences, Physics Department, University of the Free State, P.O. Box 339, Bloemfontein, 9300, Republic of South Africa
| | - M Henini
- School of Physics & Astronomy, Nottingham University, Nottingham, NG7 2RD7, UK
| | - A Gibaud
- IMMM, UMR 6283 CNRS, Bd O. Messiaen, University of Le Maine, 72085, Le Mans Cedex 09, France
| | - M Chaker
- INRS-Energie et Matériaux, 1650 Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada
| | - P Rezaee
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - N Lethole
- Department Physics, University of Fort Hare, Alice, Eastern Cape Province, South Africa
| | - M Akbari
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - R Morad
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa
| | - M Maaza
- MRD-Tandetron Accelerator & Nanosciences African Network, iThemba LABS-National Research Foundation, P O Box 722, Somerset West, 7129, Western Cape Province, South Africa.
- UNESCO-UNISA Africa Chair in Nanosciences and Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria, 003, South Africa.
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Pavoni E, Modreanu MG, Mohebbi E, Mencarelli D, Stipa P, Laudadio E, Pierantoni L. First-Principles Calculation of MoO 2 and MoO 3 Electronic and Optical Properties Compared with Experimental Data. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1319. [PMID: 37110904 PMCID: PMC10144520 DOI: 10.3390/nano13081319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 06/19/2023]
Abstract
MoO3 and MoO2 systems have attracted particular attention for many widespread applications thanks to their electronic and optical peculiarities; from the crystallographic point of view, MoO3 adopts a thermodynamically stable orthorhombic phase (α-MoO3) belonging to the space group Pbmn, while MoO2 assumes a monoclinic arrangement characterized by space group P21/c. In the present paper, we investigated the electronic and optical properties of both MoO3 and MoO2 by using Density Functional Theory calculations, in particular, the Meta Generalized Gradient Approximation (MGGA) SCAN functional together with the PseudoDojo pseudopotential, which were used for the first time to obtain a deeper insight into the nature of different Mo-O bonds in these materials. The calculated density of states, the band gap, and the band structure were confirmed and validated by comparison with already available experimental results, while the optical properties were validated by recording optical spectra. Furthermore, the calculated band-gap energy value for the orthorhombic MoO3 showed the best match to the experimental value reported in the literature. All these findings suggest that the newly proposed theoretical techniques reproduce the experimental evidence of both MoO2 and MoO3 systems with high accuracy.
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Affiliation(s)
- Eleonora Pavoni
- Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (E.P.); (E.M.); (P.S.)
| | | | - Elaheh Mohebbi
- Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (E.P.); (E.M.); (P.S.)
| | - Davide Mencarelli
- Department of Information Engineering, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (D.M.); (L.P.)
| | - Pierluigi Stipa
- Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (E.P.); (E.M.); (P.S.)
| | - Emiliano Laudadio
- Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (E.P.); (E.M.); (P.S.)
| | - Luca Pierantoni
- Department of Information Engineering, Marche Polytechnic University, Via Brecce Bianche, 60131 Ancona, Italy; (D.M.); (L.P.)
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