Biexciton Auger Recombination in Colloidal Graphene Quantum Dots

We measure biexciton Auger recombination (AR) in colloidal graphene quantum dots (GQDs) by transient absorption spectroscopy. AR is reflected in GQDs with 132 and 168 sp(2)-hybridized C atoms as a decay with a similar to 0.3 ps time constant and an amplitude depending superlinearly on pump fluence. Despite the orders-of-magnitude difference in size between GQDs and carbon nanotubes, their biexciton AR rates are similar. This similarity is a result of strong carrier interactions in sp(2)-hybridized carbon nanostructures and suggests that GQDs may hold promise in the context of carrier multiplication.