Simple synthesis of ultra-small nanodiamonds with tunable size and photoluminescence

We report on a simple method for fabricating ultra-small nanodiamonds (NDs) with size tunability and uniformity by femtosecond laser ablation in solution. photoluminescence (PL) is tailored in a broad range from ultra-violet (UV) to red region through adjusting the carbon sources or solutions. The NDs also emit multiphoton luminescence. Comprehensive discussions based on the anomalous PL behavior and well-defined absorption and excitation peaks suggest that UV emission originates from radiative recombination through intrinsic direct transitions between highly localized pi states and blue or green emission originates from radiative recombination through defect energy trapping states. (C) 2013 Elsevier Ltd. All rights reserved.