One-pot synthesis of 2,2'-dipicolylamine derived highly photoluminescent nitrogen-doped carbon quantum dots for Fe³⁺ detection and fingermark detection

The novel nitrogen-doped carbon quantum dots (N-CQDs) with high fluorescence quantum yield of 23.2% were successfully prepared via a simple hydrothermal reaction with citric acid and 2,2'-dipicolylamine. The as-prepared blue fluorescent N-CQDs had excellent water dispersibility, and showed pH and excitation-dependent emission behaviors. Noticeably, owing to the strong interaction between the residual 2,2'-dipicolylamine group on the surface of N-CQDs and Fe³⁺, the N-CQDs could be used as a turn off fluorescence probe for Fe³⁺ sensing through an electron transfer process. Moreover, the photoluminescent N-CQDs/poly(vinyl alcohol) film was further applied for latent fingermark imaging. (paper)