Size-dependent radiative decay processes in graphene quantum dots

摘要: Radiative decay processes have been studied in graphene quantum dots (GQDs) by varying their size. The photoluminescence (PL) traces are well fitted to a biexponential function with lifetimes of τ1 and τ2, indicating fast slow components, respectively. is almost constant, irrespective the average GQD size (da) for two excitation wavelengths 305 356 nm. In contrast, τ2 decreases as da increases ≤ ∼17 nm, but > it increasing both wavelengths, similar size-dependent behaviors time-integrated PL peak energy. We propose that originate from size-independent band-to-band transition resulting edge-state variation at periphery GQDs,