Optical Properties and Charge-Transfer Excitations in Edge-Functionalized All-Graphene Nanojunctions
journal contributionposted on 16.12.2015, 19:11 by Caterina Cocchi, Deborah Prezzi, Alice Ruini, Marilia J. Caldas, Elisa Molinari
We investigate the optical properties of edge-functionalized graphene nanosystems, focusing on the formation of junctions and charge-transfer excitons. We consider a class of graphene structures that combine the main electronic features of graphene with the wide tunability of large polycyclic aromatic hydrocarbons. By investigating prototypical ribbon-like systems, we show that, upon convenient choice of functional groups, low-energy excitations with remarkable charge-transfer character and large oscillator strength are obtained. These properties can be further modulated through an appropriate width variation, thus spanning a wide range in the low-energy region of the UV–vis spectra. Our results are relevant in view of designing all-graphene optoelectronic nanodevices, which take advantage of the versatility of molecular functionalization, together with the stability and the electronic properties of graphene nanostructures.