The Computational Quantum Study in Performing the Feasibility Properties as a Solar Absorption of the Graphene Nanopillars

Abstract

Graphene nanopillars is a hybrid carbon materials between graphene and carbon nanotubes which ware seamlessly combined through C-C bonding with covalent bonds. This work is considered the geometric features affecting the electronic structure and including the formation energy and the optical absorption have been examined from the molecular modeling and computation by density functional tight-binding (DFTB) methods. The two-carbon nanotubes in graphene nanopillar with zigzag(6,0), armchair(6,6), and mixed carbon nanotube zigzag(6,0)+armchair(6,6) between the two graphene sheets have been constructed for making it possible to increase the width, length and height. The results enlarge the amplitudes in the different sizes of graphene nanopillars. It was found that the formation energy of all graphene nanopillars was exothermic, i.e., forming itself without the need of energy from environment. It has a rather unique electronic structure since the changing in geometric features does not effects the electronic structure (HOMO and LUMO) of graphene nanopillars. While the energy gap, which can indicates the difficulty of electronic transition, has performs a the condition: zigzag(6,0)+armchair(6,6) > zigzag(6,0) > armchair(6,6). Finally, the optical absorption of graphene nanopillars showed a tendency to absorb light in the range of wavelengths 1,600 - 23,000 nm (or frequency range 1012-1015 Hz), which is the spectrum of infrared to visible light. This useful information could support the graphene nanopillars to be used as material for boost more efficiency in the organic solar photovoltaic cells.