Abstract Polyethyleneimine functionalized carbon quantum dots (PEI-CQDs) were synthesized by one-step hydrothermal method using biomass tar as carbon precursor, which was produced in the reduction smelting process. Based on the selective fluorescence quenching effect between Cu2+ and PEI-CQDs, the accurate and rapid detection of Cu2+ was achieved. The results showed that as-prepared PEI-CQDs were spherical particles with uniform sizes, and the average particle size was 1.98 nm. Excellent dispersibility could be obtained in aqueous solution due to the hydrophilic functional groups (such as −COOH, −NH, −CN and C−O) on the surface of PEI-CQDs. The fluorescence quantum yield of CQDs increased from 11.3% to 27.3% after PEI functionalization. Cu2+ could selectively interact with amino groups on the surface of PEI-CQDs by complexation, leading to the fluorescence quenching effect of PEI-CQDs. And the fluorescence quenching degree exhibited a linear relationship with the Cu2+ concentration ranging from 0.08 μmol/L to 400 μmol/L with a detection limit of 80 nmol/L. As fluorescent probes, PEI-CQDs have good accuracy and repeatability in Cu2+ detection, showing outstanding practical feasibility.

中文翻译：

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功能化碳量子点的合成作为用于检测 Cu2+ 的荧光探针

摘要 以还原冶炼过程中产生的生物质焦油为碳前驱体，采用一步水热法合成聚乙烯亚胺功能化碳量子点（PEI-CQDs）。基于Cu2+和PEI-CQDs之间的选择性荧光猝灭效应，实现了Cu2+的准确快速检测。结果表明，制备的 PEI-CQDs 为球形颗粒，粒径均匀，平均粒径为 1.98 nm。由于 PEI-CQDs 表面的亲水性官能团（如 -COOH、-NH、-CN 和 CO），在水溶液中可以获得优异的分散性。PEI 功能化后，CQDs 的荧光量子产率从 11.3% 增加到 27.3%。Cu2+ 可以通过络合选择性地与 PEI-CQDs 表面的氨基相互作用，导致 PEI-CQDs 的荧光猝灭效应。荧光猝灭度与Cu2+浓度呈线性关系，范围为0.08 μmol/L～400 μmol/L，检出限为80 nmol/L。作为荧光探针，PEI-CQDs 在 Cu2+ 检测中具有良好的准确性和重复性，显示出突出的实际可行性。