Controllable synthesis and Photoluminescence (PL) of amorphous and crystalline carbon nanoparticles

Carbon nanoparticles with both amorphous and crystalline structures have been prepared by irradiating carbon black in absolute ethanol using millisecond-pulsed laser. The structures of carbon nanoparticles produced in the experiment are determined by laser power density. Amorphous nanoparticles (A-nanoparticles) can be produced below 10(5) W/cm(2) while the formation of crystalline nanoparticles (C-nanoparticles) requires above 10(6) W/cm(2). Both A- and C-nanoparticles can emit strong visible light, but A-nanoparticles show multiband emission in the blue region. The possible formation mechanism of A- and C-nanoparticles and the origin of their luminescence are given in the paper. (C) 2011 Elsevier Ltd. All rights reserved.