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415 results on '"Akhavan, Omid"'

2. Rashba contribution of 2D Dirac-Weyl fermions: Beyond ordinary quantum regime

Author

Jellal, Ahmed, Jahani, Dariush, and Akhavan, Omid

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, High Energy Physics - Theory, Quantum Physics
Abstract

We study the energy levels of Dirac-Weyl fermions in graphene subject to a magnetic field with Rashba contribution in the minimal length situation. The exact solution for the energy dispersion of Dirac-like charge carriers coupled to the magnetic moments in a (2+1)-dimension is obtained by the use of the momentum space representation. Moreover, as it comes to applications for 2D Dirac-like quasiparticles, we also extend our theory and results in some special cases, showing that the emerging energy spectrum at the high magnetic field limit becomes independent of the Rashba coupling, $\lambda_{R}$, and the band index of Landau levels., Comment: 6 pages, 2 figures. Clarifications and references added. Version to appear in EPJB

Published
2022

11. Green and Sustainable Membranes: A review

Author

Rabiee, Navid, Sharma, Rajni, Foorginezhad, Sahar, Jouyandeh, Maryam, Asadnia, Mohsen, Rabiee, Mohammad, Akhavan, Omid, Lima, Eder C., Formela, Krzysztof, Ashrafizadeh, Milad, Fallah, Zari, Hassanpour, Mahnaz, Mohammadi, Abbas, and Saeb, Mohammad Reza

Published
2023
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19. Customizing nano-chitosan for sustainable drug delivery

Author

Saeedi, Mostafa, Vahidi, Omid, Moghbeli, Mohammad Reza, Ahmadi, Sepideh, Asadnia, Mohsen, Akhavan, Omid, Seidi, Farzad, Rabiee, Mohammad, Saeb, Mohammad Reza, Webster, Thomas J., Varma, Rajender S., Sharifi, Esmaeel, Zarrabi, Ali, and Rabiee, Navid

Published
2022
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20. Magnetic nanocomposites for biomedical applications

Author

Naghdi, Mina, Ghovvati, Mahsa, Rabiee, Navid, Ahmadi, Sepideh, Abbariki, Nikzad, Sojdeh, Soheil, Ojaghi, Amirhossein, Bagherzadeh, Mojtaba, Akhavan, Omid, Sharifi, Esmaeel, Rabiee, Mohammad, Saeb, Mohammad Reza, Bolouri, Keivan, Webster, Thomas J., Zare, Ehsan Nazarzadeh, and Zarrabi, Ali

Published
2022
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32. Using Cu 2 O/ZnO as Two-Dimensional Hole/Electron Transport Nanolayers in Unleaded FASnI 3 Perovskite Solar Cells.

Author

Mehrabian, Masood, Taleb-Abbasi, Maryam, and Akhavan, Omid

Subjects
SOLAR cells, ELECTRON transport, COPPER, CURRENT density (Electromagnetism), SOLAR cell efficiency, PEROVSKITE, LEAD sulfide
Abstract

A Pb-free FASnI3 perovskite solar cell improved by using Cu2O/ZnO as two-dimensional-based hole/electron transport nanolayers has been proposed and studied by using a SCAPS-1D solar simulator. To calibrate our study, at first, an FTO/ZnO/MAPbI3/Cu2O/Au multilayer device was simulated, and the numerical results (including a conversion efficiency of 6.06%, an open circuit potential of 0.76 V, a fill factor parameter of 64.91%, and a short circuit electric current density of 12.26 mA/cm2) were compared with the experimental results in the literature. Then, the conversion efficiency of the proposed FASnI3-based solar cell was found to improve to 7.83%. The depth profile energy levels, charge carrier concentrations, recombination rate of electron/hole pair, and the FASnI3 thickness-dependent solar cell efficiency were studied and compared with the results obtained for the MAPbI3-containing device (as a benchmark). Interestingly, the FASnI3 material required to obtain an optimized solar cell is one-half of the material required for an optimized MAPbI3-based device, with a thickness of 200 nm. These results indicate that developing more environmentally friendly perovskite solar cells is possible if suitable electron/hole transport layers are selected along with the upcoming Pb-free perovskite absorber layers. [ABSTRACT FROM AUTHOR]

Published
2024
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37. Some Novel Thought Experiments Involving Foundations of Quantum Mechanics and Quantum Information

Author

Akhavan, Omid

Subjects
Quantum Physics
Abstract

In this thesis, we have proposed some novel thought experiments involving foundations of quantum mechanics and quantum information theory, using quantum entanglement property. Concerning foundations of quantum mechanics, we have suggested some typical systems including two correlated particles which can distinguish between the two famous theories of quantum mechanics, i.e. the standard and Bohmian quantum mechanics, at the individual level of pair of particles. Meantime, the two theories present the same predictions at the ensemble level of particles. Regarding quantum information theory, two theoretical quantum communication schemes including quantum dense coding and quantum teleportation schemes have been proposed by using entangled spatial states of two EPR particles shared between two parties. It is shown that the rate of classical information gain in our dense coding scheme is greater than some previously proposed multi-qubit protocols by a logarithmic factor dependent on the dimension of Hilbert space. The proposed teleportation scheme can provide a complete wave function teleportation of an object having other degrees of freedom in our three-dimensional space, for the first time. All required unitary operators which are necessary in our state preparation and Bell state measurement processes are designed using symmetric normalized Hadamard matrix, some basic gates and one typical conditional gate, which are introduced here for the first time., Comment: PhD Thesis, Sharif University of Technology, July 2003, 118 pages, 26 eps figures

Published
2004

43. Effects of electron transport layer type on the performance of Pb-free Cs2AgBiBr6 double perovskites: a SCAPS-1D solar simulator–based study.

Author

Mehrabian, Masood, Taleb-Abbasi, Maryam, and Akhavan, Omid

Subjects
ELECTRON transport, COPPER-zinc alloys, PEROVSKITE, SOLAR cells, OPEN-circuit voltage, METHYL formate, SHORT circuits
Abstract

Recently, due to the superior stability and lower risk of toxicity, the development of Pb-free halide double perovskite materials has revived excellent interest. In this work, Pb-free perovskite solar cells (PSCs) with ITO/ETL/Cs2AgBiBr6/Cu2O/Au multilayer structures with Cs2AgBiBr6 double perovskite as the solar light absorber layer, some electron transport layers (ETLs) and Cu2O as a hole transport layer have been introduced. Then, the effects of various thicknesses of the absorber layer and also ETL materials, like ZnO, C60, CdS, SnO2, phenyl-C61-butyric acid methyl ester (PCBM), and TiO2, on the device performance (including photoelectronic conversion efficiency (PCE), fill factor (FF%), short circuit current density (Jsc), and open-circuit voltage (VOC)) were examined with the help of a solar cell simulator (SCAPS-1D). It is noteworthy that, in the case of all ETL materials, the optimal thickness of the absorber layer was determined to be 400 nm. Then, the maximum PCE values of 20.08%, 17.63%, 14.07%, 12.11%, 14.94%, and 18.83% were obtained for the solar cells containing ZnO, C60, CdS, SnO2, PCBM, and TiO2 as the ETL, respectively. These results show that designing/developing Pb-free halide double perovskite devices having comparable PCEs with the Pb-based PSCs is feasible, provided that proper/compatible materials will be used in the multilayer structure of the next generations of solar cells. [ABSTRACT FROM AUTHOR]

Published
2023
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45. Green (Nano)membranes: A review

Author

Rabiee, Navid, primary, Sharma, Rajni, additional, Foorginezhad, Sahar, additional, Jouyandeh, Maryam, additional, Asadnia, Mohsen, additional, Rabiee, Mohammad, additional, Akhavan, Omid, additional, Lima, Eder C., additional, Formela, Krzysztof, additional, Ashrafizadeh, Milad, additional, Fallah, Zari, additional, Hassanpour, Mahnaz, additional, Mohammadi, Abbas, additional, and Saeb, Mohammad Reza, additional

Published
2023
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48. Antibacterial Nanomaterials:Mechanisms, Impacts on Antimicrobial Resistance and Design Principles

Author

Xie, Maomao, Gao, Meng, Yun, Yang, Malmsten, Martin, Rotello, Vincent M. M., Zboril, Radek, Akhavan, Omid, Kraskouski, Aliaksandr, Amalraj, John, Cai, Xiaoming, Lu, Jianmei, Zheng, Huizhen, Li, Ruibin, Xie, Maomao, Gao, Meng, Yun, Yang, Malmsten, Martin, Rotello, Vincent M. M., Zboril, Radek, Akhavan, Omid, Kraskouski, Aliaksandr, Amalraj, John, Cai, Xiaoming, Lu, Jianmei, Zheng, Huizhen, and Li, Ruibin

Abstract

Antimicrobial resistance (AMR) is one of the biggest threats to the environment and health. AMR rapidly invalidates conventional antibiotics, and antimicrobial nanomaterials have been increasingly explored as alternatives. Interestingly, several antimicrobial nanomaterials show AMR-independent antimicrobial effects without detectable new resistance and have therefore been suggested to prevent AMR evolution. In contrast, some are found to trigger the evolution of AMR. Given these seemingly conflicting findings, a timely discussion of the two faces of antimicrobial nanomaterials is urgently needed. This review systematically compares the killing mechanisms and structure-activity relationships of antibiotics and antimicrobial nanomaterials. We then focus on nano-microbe interactions to elucidate the impacts of molecular initiating events on AMR evolution. Finally, we provide an outlook on future antimicrobial nanomaterials and propose design principles for the prevention of AMR evolution.

Published
2023

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