Multiple-color-emissive carbon dots (CDs) is one of the hotspots due to its potential in multi-fields. However, the exploring of efficient synthetic strategies and emission mechanisms still remain challenging. Herein, we report a facile solvothermal route to prepare CDs with tunable photoluminescence (PL) from green to red via a novel PL-tuning strategy of sulfur doping and water engineering. By detailed characterizations and comparison, it is demonstrated that the S doping can significantly increase the content of graphitic nitrogen, resulting in the fluorescence shifting from green to yellow; on the other hand, water engineering is able to yield carboxyl group and enhance surface oxidation degree, which can further facilitate the PL shifting from yellow to red. Owning to multicolor emissions and S doping, the prepared PL-tunable CDs present versatility in various applications including fluorescent films, light-emitting diodes (LED), bioimaging probe and highly sensitive Fe³⁺ detector.

多色发射碳点（CD）是热点之一，因为它在多领域具有潜力。然而，探索有效的合成策略和排放机制仍然具有挑战性。在这里，我们报告了一种简便的溶剂热途径，通过硫掺杂和水工程学的新型PL调谐策略，可以将CD的光致发光（PL）从绿色变为红色。通过详细的表征和比较，表明S掺杂可以显着增加石墨氮的含量，从而导致荧光从绿色变为黄色。另一方面，水工程能够产生羧基并增强表面氧化度，这可以进一步促进PL从黄色变为红色。由于多色发射和S掺杂，³⁺检测器。