title: Study of Electronic, Optical Absorption and Emission in Pure and Metal-Decorated Graphene Nanoribbons (C29 H14 -X; X=Ni, Fe, Ti, Co(+) , Al(+) , Cu(+) ): First Principles Calculations.
abstract: Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were performed with the basis sets 6-31G for DFT and 6-31G(d), 6-31+G(d,p) for TDDFT on pure graphene nanoribbon (GNR) C30 H14 and metal-decorated C29 H14 -X (MGNRs; X=Ni, Fe, Ti, Co(+) , Al(+) , and Cu(+) ). The metal/carbon ratio (X:C 3.45 %) and the doping site were fixed. Electronic properties, that is, the dipole moment, binding energy, and HOMO-LUMO gaps, were calculated. The absorption and emission properties in the visible range (λ=400-720 nm) were determined. Optical gaps, absorption and emission wavelengths, oscillator strengths, and dominant transitions were calculated. Pure graphene was found to be the most stable form. However, of the MGNRs, C29 H14 Co(+) and C29 H14 Al(+) were found to be the most and least stable, respectively. All GNRs were found to have semiconducting nature. The optical absorption of pure graphene undergoes a shift on metal doping. Emission from the pure graphene followed Kasha's rule, unlike the metal-doped GNRs.
authors: Department of Physics, AIAS, Amity University, Noida (India). schopra1@amity.edu.
authors: Siddheshwar
authors: S
authors: Chopra
keywords: absorption; density functional calculations; doping; emission; graphene