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The field of Two Dimensional (2D) materials has been extensively studied since their discovery in 2004, owing to their remarkable combination of properties. My thesis focuses on exploring novel 2D materials such as Graphene Nanoribbon (GNR), holey carbon nitride C2N, and MXenes for energy storage, gas sensing, and spintronic applications, utilizing state-of-the-art techniques that combine Density Functional Theory (DFT) and Non-Equilibrium Greens Functions (NEGF) formalism; namely Vienna Ab-initio Simulation Package (VASP) and Atomistic Toolkit (ATK) package. Firstly, on the side of gas sensing, the burning of fossil fuels raises the level of toxic gas and contributes to global warming, necessitating the development of highly sensitive gas sensors. To start with, the adsorption and gas-sensing properties of bilaterally edge doped (B/N) GNRs were investigated. The transport properties revealed that the bilateral B/N edge-doping of GNR yielded Negative Differential Resistance (NDR) IV-characteristics, due to the electron back-scattering which was beneficial for selective gas sensing applications. Therefore, both GNR: B/N were found to be good sensors for NO2 and SO3 respectively. After that, the catalytic activity of four magnetic transition metal “TM” elements (e.g., Mn, Fe, Co and Ni) embedded in C2N pores, as Single-Atom Catalysts (SAC), was tested towards detecting toxic oxidizing gases. The results of spin-polarized transport properties revealed that Ni- and Fe-embedded C2N are the most efficient in detecting NO/ NO2 and NO2 molecules. Secondly, on the side of energy storage, since the fossil fuels reserves are depleting at an alarming rate, there is an urgent need for alternative forms of energy to meet the ever-growing demand for energy. Hydrogen is a popular form of clean energy. However, its storage and handling are challenging because of its explosive nature. The effect

Gas-sensing properties of nitrogenated holey graphene (C2N), graphdiyne (GDY) and their van der Waals heterostructure (C2N…GDY) have been studied towards particular volatile organic compounds (VOCs) by means of spin-polarized, dispersion-corrected DFT calculations. We find that VOCs such as acetone, ethanol, propanal, and toluene interact weakly with the GDY monolayer; however, the bindings are significantly enhanced with the C2N monolayer and the hybrid C2N…GDY heterostructure in AB stacking. Electron localization function (ELF) analysis shows that all VOCs are van der Waals bound (physical binding) to the 2D materials, which result in significant changes of the charge density of C2N and GDY monolayers and the C2N…GDY heterostructure. These changes alter the electronic properties of C2N and GDY, and the C2N…GDY heterostructure, upon VOC adsorption, which are investigated by density-of-states plots. We further apply thermodynamic analysis to study the sensing characteristics of VOCs under varied conditions of pressure and temperature. Our findings clearly indicate that the C2N…GDY heterostructure is a promising material for sensing of certain VOCs.

Gas-sensing properties of nitrogenated holey graphene (C2N), graphdiyne (GDY) and their van der Waals heterostructure (C2N…GDY) have been studied towards particular volatile organic compounds (VOCs) by means of spin-polarized, dispersion-corrected DFT calculations. We find that VOCs such as acetone, ethanol, propanal, and toluene interact weakly with the GDY monolayer; however, the bindings are significantly enhanced with the C2N monolayer and the hybrid C2N…GDY heterostructure in AB stacking. Electron localization function (ELF) analysis shows that all VOCs are van der Waals bound (physical binding) to the 2D materials, which result in significant changes of the charge density of C2N and GDY monolayers and the C2N…GDY heterostructure. These changes alter the electronic properties of C2N and GDY, and the C2N…GDY heterostructure, upon VOC adsorption, which are investigated by density-of-states plots. We further apply thermodynamic analysis to study the sensing characteristics of VOCs under varied conditions of pressure and temperature. Our findings clearly indicate that the C2N…GDY heterostructure is a promising material for sensing of certain VOCs., QC 20200617