Nitrogen-doped carbon dots derived from polyamindoamine dendrimer

Nitrogen-doped carbon dots (CDs) were synthesized through a hydrothermal process by using N-riched polyamindoamine (PAMAM) dendrimer as the precursor. The CDs depict bright blue fluorescence with the quantum yield (QY) of 40%, and show excellent monodispersity and solubility in water. The CDs also demonstrate sensitive detection of Fe³⁺ ions (ppm level). For more practical applications, the as-prepared CDs could be ink candidates for nano-printing patterns, which are highly fluorescent. Also, we have found the pH values and solvents used in the ink have great influence on the intensity of their fluorescence. More interestingly, we prepared poly(N-isopropylacrylamide) (PNIPAM) and CDs hybrids, which exhibit temperature switching properties. They were reversibly sensitive to external temperatures ranging from 20 °C to 40 °C, making it possible to develop CD-based thermosensitive devices or sensors.