  In recent years there has been significant debate on whether the edge type of
graphene nanoflakes (GNF) or graphene quantum dots (GQD) are relevant for their
electronic structure, thermal stability and optical properties. Using computer
simulations, we have proven that there is a fundamental difference in the
calculated absorption spectra between samples of the same shape, similar size
but different edge type, namely, armchair or zigzag edges. These can be
explained by the presence of electronic structures near the Fermi level which
are localized on the edges. These features are also evident from the dependence
of band gap on the GNF size, which shows three very distinct trends for
different shapes and edge geometries.
