Photoluminescent colloidal Cu@C-NPs suspensions synthesized by LASL

In this work we report the synthesis of photoluminescent carbon-coated copper nanoparticles (Cu@C-NPs) based colloidal suspensions, using the laser ablation of solids in liquids technique (LASL). LASL experiments were carried out by ablating a Cu solid target immersed in acetone as the liquid medium with ns-laser pulses (1064 nm) of a Nd-YAG laser. In all experiments the per pulse laser fluence and the repetition rate frequency were kept constant and the ablation time was varied. The as obtained Cu@C-NPs suspensions were optically characterized with absorption and photoluminescence spectroscopies. Raman spectroscopy was used to give evidence of the carbon shell deposited around the Cu NPs. TEM results showed that 10 nm spheroids Cu@C-NPs were obtained. The as obtained Cu@C-NPs suspensions displayed out a PL emission band similar to that for carbon nanoparticles suspensions obtained by the same technique. We have found that the blue-green PL emission band intensity is mainly dependent on the ablation and aging time of the samples. The Cu@C-NPs-based colloidal suspensions can be proposed as multifunctional due to its absorbance and emission properties.