London Centre for Energy Engineering (LCEE), School of Engineering, London South Bank University, 103 Borough Road, London, SE1 0AA, UK.
National Institute of Materials Physics, Atomistilor 405A, 077125, Magurele, Ilfov, Romania.
Sci Rep. 2022 Aug 15;12(1):13806. doi: 10.1038/s41598-022-16893-x.
Carbon quantum dots (CQDs) derived from biomass, a suggested green approach for nanomaterial synthesis, often possess poor optical properties and have low photoluminescence quantum yield (PLQY). This study employed an environmentally friendly, cost-effective, continuous hydrothermal flow synthesis (CHFS) process to synthesise efficient nitrogen-doped carbon quantum dots (N-CQDs) from biomass precursors (glucose in the presence of ammonia). The concentrations of ammonia, as nitrogen dopant precursor, were varied to optimise the optical properties of CQDs. Optimised N-CQDs showed significant enhancement in fluorescence emission properties with a PLQY of 9.6% compared to pure glucose derived-CQDs (g-CQDs) without nitrogen doping which have PLQY of less than 1%. With stability over a pH range of pH 2 to pH 11, the N-CQDs showed excellent sensitivity as a nano-sensor for the highly toxic highly-pollutant chromium (VI), where efficient photoluminescence (PL) quenching was observed. The optimised nitrogen-doping process demonstrated effective and efficient tuning of the overall electronic structure of the N-CQDs resulting in enhanced optical properties and performance as a nano-sensor.
碳量子点（CQDs）来源于生物质，是一种被提议的绿色纳米材料合成方法，通常具有较差的光学性质和较低的光致发光量子产率（PLQY）。本研究采用环保、经济高效的连续水热流合成（CHFS）工艺，从生物质前体（氨存在下的葡萄糖）合成高效的氮掺杂碳量子点（N-CQDs）。改变氨的浓度（作为氮掺杂剂前体）以优化 CQDs 的光学性质。优化后的 N-CQDs 与未掺杂氮的纯葡萄糖衍生的 CQDs（g-CQDs）相比，荧光发射性能显著增强，PLQY 为 9.6%，而 g-CQDs 没有氮掺杂，PLQY 小于 1%。N-CQDs 在 pH 2 到 pH 11 的范围内具有稳定性，作为一种对高毒性高污染的铬（VI）的纳米传感器具有出色的灵敏度，观察到有效的光致发光（PL）猝灭。优化的氮掺杂过程有效地调节了 N-CQDs 的整体电子结构，从而增强了光学性质，并提高了作为纳米传感器的性能。
