Carbon dots (CDots) are characterized by their optical properties including strong absorptions, bright fluorescence emissions, and electron acceptor and donor behaviors in the visible spectrum. In this study, aconitic acid and oligomeric polyethyleneimine were used as precursors to prepare PEI/AA-CDots by vigorous microwave-assisted thermal carbonization. The as-prepared CDots exhibit excitation wavelength-dependent fluorescence with a quantum yield of 44.2% at the excitation wavelength of 380 nm. In addition, the fluorescence in the visible spectrum can be selectively and efficiently quenched by Cu²⁺ or Hg²⁺ ions via electron transitions due to the electron donor behaviors of the as-prepared CDots. The detection limits of Cu²⁺ and Hg²⁺ ions are 70 and 84 nM, respectively. The quenched fluorescence can be recovered by introducing aspartic acid or L-cysteine into the PEI/AA-CDots-Cu²⁺ or the PEI/AA-CDots-Hg²⁺ systems. Furthermore, the as-prepared PEI/AA-CDots can be successfully applied for detecting Cu²⁺ and Hg²⁺ ions in real water and can serve as a potential candidate as a probe for detecting these metal ions.

碳点（CDot）的光学特性包括强吸收，明亮的荧光发射以及可见光谱中的电子受体和施主行为。在这项研究中，乌头酸和低聚聚乙烯亚胺被用作前体，通过剧烈的微波辅助热碳化法制备PEI / AA-CDots。所制备的CDots显示出与激发波长有关的荧光，在380nm的激发波长下量子产率为44.2％。另外，由于所制备的CDot的电子给体行为，可见光谱中的荧光可以通过电子跃迁被Cu ²⁺或Hg ²⁺离子选择性地和有效地猝灭。Cu ²⁺和Hg ²⁺的检出限离子分别为70和84 nM。可以通过将天冬氨酸或L-半胱氨酸引入PEI / AA-CDots-Cu ²⁺或PEI / AA-CDots-Hg ²⁺系统中来恢复猝灭的荧光。此外，所制备的PEI / AA-CDots可以成功地用于检测真实水中的Cu ²⁺和Hg ²⁺离子，并且可以作为潜在的候选物来检测这些金属离子。