Water soluble carbon nanoparticles: Hydrothermal synthesis and excellent photoluminescence properties

Water-soluble carbon nanoparticles (CNPs) were fabricated by a facile, one step hydrothermal synthetic route using acid/alkali as additives. These CNPs emit bright photoluminescence (PL) covering the entire visible-near infrared (NIR) spectral range. PL measurements confirmed that the CNPs have up-conversion of PL properties, and that the NIR PL of the CNPs can also be observed by NIR excitation. Control experiments indicated that different additives can strongly affect the PL properties of the CNPs. With a combination of free dispersion in water and attractive PL properties, these CNPs hold promise for applications in nanotechnology.