Surface passivation of carbon nanoparticles with p-phenylenediamine towards photoluminescent carbon dots

The versatility of the surface chemistry of carbon dots (CDs) can generate high flexibility in engineering their surface functionality for a wide and precise array of applications. In respect of this, we perform for the first time the surface passivation of carboxylated carbon nanoparticles with p-phenylenediamine to prepare water soluble photoluminescent CDs exhibiting intriguing physicochemical properties. The new strategy used to engineer the surface functionality allows us to synthesize CDs with a stable excitation independent green photoluminescence with a quantum yield of 14% and lifetime of 11.8 ns, suitable for application in bioimaging, sensing and optoelectronics.