Interband π Plasnnon of Graphene Nanopores: A Potential Sensing Mechanism for DNA Nucleotides

We propose a potential sensing mechanism for DNA nucleotides using the interband pi surface plasmon resonance (SPR) of graphene nanopores. The SPR and field-enhancement properties were investigated using the discrete dipole approximation (DDA) and the finite-difference-time-domain (FDTD) methods, respectively. For graphene nanopores smaller than 10 nm in length, increasing the pore diameter red shifts the SPR peak wavelength, and for larger sheets, the SPR peak wavelength is essentially unchanged by variations in the pore diameter. Presentation of a single nucleotide to the pore significantly changes the SPR properties of the graphene nanopore, and each nucleotide has unique SPR properties. Each nucleotide induces a shift of 2-12 nm in the peak wavelength of each SPR mode, and if all of the modes are considered simultaneously, the type of DNA nucleotide present can be dearly determined. Our results show that the small-size-sensitive interband plasmon in graphene nanopore is probably applicable as a new sensing mechanism for DNA nucleotides.