Effects of vacancies and divacancies on the failure of C3N nanosheets

Abstract

Two-dimensional materials, and especially carbon-based 2D materials, have gained a special reputation and status in many engineering fields and applications recently; because they can be engineered by various methods to precisely yield the properties desired by the designers. One of the most important techniques used for engineering these structures is to create nanopores in them. The varied effects of nanopores in graphene sheets and some other 2D materials have already been studied. In this work, for the first time, the effects of nanopores on the mechanical properties of C3N sheets have been evaluated. Using the molecular dynamics method, various types of achievable vacancy and divacancy pores in C3N sheets have been specified, and the formation energy for each type has been calculated. The formation energy for a vacancy formed by removing a carbon atom or a nitrogen atom is 2.63 eV or 1.31 eV, respectively. In comparing the formation energies for different types of vacancies and divacancies, it was observed that the removal of carbon atom in the structure of C3N requires much more energy, and that the highest amount of energy is needed for removing two carbon atoms in two types of divacancies. Since graphene sheets with a large number of vacancies do not fail easily and remain intact, these sheets can be considered as suitable candidates for ‘straintronic’ applications. By studying the effect of pore density on the mechanical properties of C3N sheets it was observed that at pore densities lower than 5%, C3N sheets exhibit better mechanical properties than graphene, and thus, they can be a better option for straintronic applications.