Fluorescent carbon quantum dots (CQDs) doped with heteroatoms are highly promising for diverse applications ranging from bioimaging to environmental sensing. However, the ability for doping and functionalizing CQDs in a continuous, scalable, industry-relevant flow chemistry process, remains limited. Here we overcome this limitation by developing a continuous, facile and efficient method for the preparation of nitrogen and phosphorus co-doped carbon quantum dots (NP-CQDs), using microflow reactors combined with localized, energy-efficient heating of ethanolamine and phosphoric acid aqueous solution. The products are characterized by advanced microanalysis including fluorescence spectrophotometry, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) measurements. The results show ultrasmall fluorescent CQDs with narrow size distribution were successfully prepared, where N and P atoms proved to be effectively doped into the CQDs. The reaction conditions for the continuous synthesis of CQDs are investigated, including the influence of residence time and reaction temperature on the obtained CQDs (particle size, distributions, fluorescence intensity, bandgap energies, conductivity, and fluorescence lifetime) are analyzed. This study is expected to provide guidance for the continuous and controllable preparation of fluorescent CQDs with effective doping of heteroatoms.

掺杂杂原子的荧光碳量子点 (CQD) 在从生物成像到环境传感的各种应用中极具前景。然而，在连续的、可扩展的、与行业相关的流动化学过程中掺杂和功能化 CQD 的能力仍然有限。在这里，我们通过开发一种连续、简便和有效的方法来制备氮和磷共掺杂碳量子点 (NP-CQD)，使用微流反应器结合乙醇胺和磷酸水溶液的局部节能加热来克服这一限制。解决方案。产品通过先进的微量分析进行表征，包括荧光分光光度法、透射电子显微镜 (TEM)、X 射线光电子能谱 (XPS) 和 X 射线衍射 (XRD) 测量。结果表明，成功制备了具有窄尺寸分布的超小荧光 CQD，其中 N 和 P 原子被证明有效地掺杂到 CQD 中。研究了连续合成碳量子点的反应条件，包括停留时间和反应温度对获得的碳量子点的影响（粒径、分布、荧光强度、带隙能量、电导率和荧光寿命）。该研究有望为有效掺杂杂原子的荧光碳量子点的连续可控制备提供指导。包括停留时间和反应温度对获得的 CQDs（粒径、分布、荧光强度、带隙能量、电导率和荧光寿命）的影响进行了分析。该研究有望为有效掺杂杂原子的荧光碳量子点的连续可控制备提供指导。包括停留时间和反应温度对获得的 CQDs（粒径、分布、荧光强度、带隙能量、电导率和荧光寿命）的影响进行了分析。该研究有望为有效掺杂杂原子的荧光碳量子点的连续可控制备提供指导。