Fluorescent carbon dots doped with nitrogen for rapid detection of Fe (III) and preparation of fluorescent films for optoelectronic devices.

• A N CDs synthesized by citric acid and dopamine HCl with a quantum yield of 15.7 % was investigated. • N CDs exhibits excellent sensitivity and selectivity toward Fe3+ in a wide range of 40–500 μΜ. • The N CDs/PVA composite film with bright blue light emission exhibits excitation independence. The paper presents a green and easily prepared water-soluble fluorescent nitrogen doped carbon dots (N CDs) synthesized by one-step hydrothermal process. The N CDs displays brilliant blue fluorescence excited by UV light, with excellent water solubility, and a quantum yield of 15.7 %. The fluorescence intensity of N CDs remains unchanged after 48 h of exposure to ultraviolet light, exhibiting good photostability. Moreover, the ion sensing characteristics of these N CDs have been explored for more than a dozen anions and cations. The result reflects that this fluorescent CDs exhibits excellent sensitivity and selectivity for Fe3+ within a range spanning of 40 ∼ 500 μΜ with a limit of detection down to 0.22 μΜ. The principle of sensor sensing is likely related to the formation of the internal filtering effect (IFE), which leads to a decline in the fluorescence intensity of N CDs in aqueous solutions containing Fe3+. Due to the excellent water solubility, good photostability and high yield of N CDs, the application of prepared N CDs/polyvinyl alcohol (PVA) as fluorescent materials for white LED devices was explored. The prepared N CDs/PVA (NCP) composite film can also exhibit bright blue light under 365 nm excitation, indicating good application prospects in the area of white LED devices and agricultural films. [Display omitted] [ABSTRACT FROM AUTHOR]