Laser synthesis and size tailor of carbon quantum dots

Carbon quantum dots (C-dots) with average sizes of about 3, 8, and 13 nm were synthesized by laser irradiation of graphite flakes in polymer solution. The obtained C-dots display size and excitation wavelength dependent photoluminescence behavior. The size control of C-dots can be realized by tuning laser pulse width. The original reason could be the effects of laser pulse width on the conditions of nucleation and growth of C-dots. Compared with short-pulse-width laser, the long-pulse-width laser would be better fitted to the size and morphology control of nanostructures in the different material systems.