Electronic transport properties of pristine, homogenously and heterogeneously boron-nitrogen doped saw-tooth penta-graphene nanoribbon (SPGNR) with carbon nanotube electrodes have been studied using Extended Huckel Theory in combination with the non-equilibrium Green's function formalism. CNT electrodes produce a remarkable increase in current at higher bias voltages in pristine SPGNR. The current intensity is maximum at higher bias voltages, while the nitrogen-doped model shows current from the onset of the bias voltage. However, there are also considerable differences in the I-V curves associated with the pristine model and other models doped homogenously as well as heterogeneously with boron and nitrogen. The doped models also exhibit a small negative differential resistance effect, with much prominence in the nitrogen-doped model. In summary, our findings show clearly that doping can effectively modulate the electronic and the transport properties of penta-graphene nanoribbons that have not been studied and reported thus far.
This work reports the modeling and simulation of gas sensors made from pristine graphene nanoplatelets (P-GnPs) using COMSOL Multiphysics software. The mass balance equation was solved while including contributions of electromigration flux.An example GnP-based gas sensor was simulated to undergo exposure to NO 2 and CO gases at different concentrations to understand the effects of adsorption. Various electrical properties and the overall sensor responses were also studied as a function of gas concentration in order to determine how viable such sensors could be for target gases. The results herein show that the resistance of the P-GnP-based gas sensor decreases when exposed to NO 2 gas whereas an opposite trend is seen when CO gas is used for exposures, ultimately suggesting that the P-GnPs exhibit p-type behavior.Sensitivities of 23 % and 60 % were achieved when the P-GnP-based gas sensor was exposed to 10 mol/m 3 concentration of NO 2 and CO at room temperature, respectively.The data heavily suggest that a higher sensitivity towards CO may be observed in future sensors. These simulations will benefit research efforts by providing a method for predicting the behavior of GnP-based gas sensors.
Graphene nanoplatelets (GnPs) are promising candidates for gas sensing applications because they have a high surface area to volume ratio, high conductivity, and a high temperature stability. Also, they cost less to synthesize, and they are lightweight, making them even more attractive than other 2D carbon-based materials. In this paper, the surface and structural properties of pristine and functionalized GnPs, specifically with carboxyl, ammonia, carboxyl, nitrogen, oxygen, fluorocarbon, and argon, were examined with Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction (XRD) to determine the functional groups present and effects of those groups on the structural and vibrational properties. We attribute certain features in the observed Raman spectra to the variations in concentration of the functionalized GnPs. XRD results show smaller crystallite sizes for functionalized GnPs samples that agree with images acquired with scanning electron microscopy.Lastly, a molecular dynamics simulation is employed to gain a better understanding of the Raman and adsorption properties of pristine GnPs.
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