Stable blue fluorescent nitrogen doped carbon dots (N-CDs) with a very high quantum yield up to 81% has been reported for the first time. Novel N-CDs were synthesized through an efficient and rapid one-step hydrothermal synthesis process from diethylenetriamine as nitrogen source and a novel carbon source trans-aconitic acid. The nanosized particles of N-CDs were in the range of 2–8 nm and uniformly distributed in molecular level. The N-CDs showed high selectivity toward Fe³⁺ with low detection limit of 10.42 nmol L⁻¹ (with corresponding linear range of 2–50 μmol L⁻¹) enabling them for ion detection application and also exhibited high fluorescence stability in extreme pH conditions. Novel N-CDs also presented a green emission shift under acidic condition (pH~2) which makes them a potential sensing probe for security papers, food packaging and bio-medical detection sensors. A security paper sensor device has been fabricated and its operation function has been validated by making real time detection of color. The novel and facile to manufacture carbon dots has potential applications ranging from biological nano-sensors for security document to color-switch sensing and bio-imaging.

首次报道了稳定的蓝色荧光氮掺杂碳点（N-CD），其量子产率高达81％。通过以二亚乙基三胺为氮源和新型碳源反乌头酸，通过高效，快速的一步水热合成工艺合成了新型N-CD。N-CDs的纳米颗粒在2-8 nm范围内，并且在分子水平上均匀分布。N-CD对Fe ^3+的选择性高，检出限低至10.42 nmol L ^-1（线性范围为2-50μmolL ^-1）使它们能够用于离子检测应用，并且在极端pH条件下也显示出高荧光稳定性。新型N-CD在酸性条件下（pH〜2）也呈现绿色发射变化，这使其成为用于防伪纸，食品包装和生物医学检测传感器的潜在传感探针。已经制造出一种安全纸传感器设备，并且通过进行实时颜色检测来验证其操作功能。这种新颖且易于制造的碳点具有潜在的应用范围，从用于安全文档的生物纳米传感器到颜色切换传感和生物成像。