The optoelectronic behaviour of carbon nanoparticles: evidence of the importance of the outer carbon shell

The particular properties of carbon nanoparticles (CNPs) have generated great interest in biomedicine, bioanalysis and optoelectronics. However, an association between the CNPs' physicochemical properties with their molecular and morphological characteristics is, even today, a topic of discussion. In this work, we use a simple method of synthesis with the ultimate aim of elucidating the structural nature of the obtained CNPs and its relationship with their well-known fluorescent properties. The sample is studied by high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), nuclear magnetic resonance (NMR), UV-visible and IR spectroscopy, electrochemistry and electrogenerated chemiluminescence (ECL). The results showed that the nanoparticles are constituted by a graphitic core surrounded by an amorphous layer, which seems to be significant in the determination of the optical and electronic properties observed in the system under study.