Nitrogen and phosphorus co-doped carbon dots derived from lily bulbs for copper ion sensing and cell imaging

A straightforward, rapid, and environmentally-friendly technique was developed for the synthesis of nitrogen and phosphorus co-doped fluorescent carbon dots (CDs) with the use of lily bulbs (LB) as raw materials. The as synthesized LB-CDs showed high stability in aqueous solution and high fluorescence with a quantum yield (QY) of 17.6%. The LB-CDs were then used as a fluorescence sensor for Cu2+ ion detection based on the Cu2+-ionstimulated fluorescence quenching of LB-CDs. The synthesized LB-CDs demonstrated exceptional selectivity and sensitivity to Cu2+ ions, with a limit of detection of 12.8 nM and a linear detection range of 0.05-2.0 mu M. The synthesized LB-CDs were also applied for the detection of Cu2+ ions in real water samples. Moreover, the LB-CDs exhibited low cytotoxicity, which is suitable for fluorescence-based analysis and cell imaging.