Abstract A one-step direct pyrolysis method without any post-treatment steps and a mass yield of up to 69% was realized for preparing N-doped carbon dots (NCDs). The NCDs exhibit excellent excitation-independent blue fluorescence with quantum yield (QY) of 65.5%, and their luminescence mechanism was explored based on optical properties and structural composition, which mainly originates from surface state photoluminescence (PL). The NCDs display highly selective and sensitive detection of Fe3+ in tris-HCl buffer system, a good linear relationship between PL intensity ratios and Fe3+concentrations was obtained in concentration range of 0 to 400 μM with a low LOD of 0.703 μM. The formation of ferric hydroxide colloid is the main reason for the specific recognition of Fe3+ by NCDs, and buffer solution plays a key role in the formation of ferric hydroxide colloid and selective detection of Fe3+. The sensing mechanism is a dynamic quenching electron transfer process in the action of hydrogen bonding and colloidal adsorption. Three real water samples were applied to evaluate actual application of NCDs probe, satisfactory recoveries (93.5%–105.6%) indicate that NCDs has great practical potential for detection of metal ions in environmental water assays.

中文翻译：

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非激发态碳点的大规模直接热解合成及三价铁离子传感机制分析

摘要 实现了一种无需任何后处理步骤且质量产率高达69%的一步直接热解法制备N掺杂碳点（NCDs）。NCDs表现出优异的与激发无关的蓝色荧光，量子产率（QY）为65.5%，基于光学性质和结构组成探索了它们的发光机制，主要来源于表面态光致发光（PL）。NCDs 在 tris-HCl 缓冲系统中显示出对 Fe3+ 的高选择性和灵敏检测，在 0 到 400 μM 的浓度范围内获得了 PL 强度比与 Fe3+浓度之间良好的线性关系，LOD 低至 0.703 μM。氢氧化铁胶体的形成是NCDs特异性识别Fe3+的主要原因，缓冲液在氢氧化铁胶体的形成和Fe3+的选择性检测中起关键作用。传感机制是在氢键和胶体吸附作用下的动态猝灭电子转移过程。应用三个真实水样来评估 NCDs 探针的实际应用，令人满意的回收率（93.5%–105.6%）表明 NCDs 在环境水分析中检测金属离子具有很大的实际潜力。