Preparation of blue luminescence gold quantum dots using laser ablation in aromatic solvents

Gold quantum dots (GQDs) have significant applications in the biomedical field, solar cells and light-emitting diodes. Synthesis of three various types of blue fluorescent GQDs are carried out for the first time by Nd: YAG laser ablation of Au target in aromatic solvent. The laser fluence used in this experiment was 0.2 J/cm(2). The characteristics of the as-prepared GQDs are confirmed by UV-vis, transmittance electron microscopy, X-ray diffraction, photoelectron spectroscopy and photoluminescence (PL). Pure and ligand-free gold quantum dots as a new type of fluorescent material are prepared through a one-step novel method. The results suggest that the molecule-like structure of GQDs is proven by the optical band energy gap (E-g = 2.54 eV), PL (lambda(em) = 427 nm, 1.76% quantum yield) and quantum confinement of an ultra-tiny size (similar to 1 nm). GQDs particles size of about 1 nm obtained by laser ablation in aromatic medium are reported for the first time. The blue luminescent and high purity of GQDs can be used efficiently for important applications, such as biosensor, bioimaging and bio-diagnosis.