Synthesis and size control of carbon quantum dots by tailoring laser parameters

Carbon quantum dots (C-dots) were synthesized by laser irradiation graphite flakes in polymer solution and display size and excitation wavelength dependent photoluminescence (PL) behavior. Our studies show that the size distribution of C-dots can be controlled by tuning laser pulse width and affects fluorescence quantum yield (FQY) of C-dots. FQY of C-dots from 0.4 ms pulse width is above five times higher than that from 2.0 ms pulse width. The possible mechanism of one-step synthesis and size control of C-dots via laser irradiation was also proposed in the present work.