Abstract The nanocomposites prepared by the combination of SiO2 and carbon quantum dots (CQDs) have the advantages of low toxicity, high fluorescence intensity, high biocompatibility and good water solubility, which greatly broaden its application range. Nevertheless, if only SiO2 and CQDs are simply combined without any structural design, the stability of the nanocomposites will be poor, which will affect its practical application value. In this work, we first synthesized ordered mesoporous silica (OMS) rapidly in aqueous solution by a facile method (30 min), and then generated CQDs in situ in the mesoporous channels of OMS by hydrothermal method to obtain CQDs@OMS fluorescent nanocomposites. The chemical structure and morphology of OMS and CQDs@OMS were characterized by FT-IR, XRD, SAXRD and TEM, indicating that CQDs was successfully encapsulated in OMS. The stability test results of CQDs@OMS indicate that CQDs can be stably present in the mesoporous channels of OMS, and the fluorescence intensity of CQDs@OMS nanocomposites is almost independent of ionic strength, pH and storage time. The optical performance results show that the optimal excitation wavelength of CQDs@OMS nanocomposites is about 340 nm, the emission wavelength is about 440 nm. Using CQDs@OMS nanocomposites as fluorescent probes to detect Fe3+, it was found that CQDs@OMS responded very quickly to Fe3+. The fluorescence quenching intensity of CQDs@OMS has a good linear relationship with the concentration of Fe3+ in the range of 25–750 μM. Therefore, the trace amount of Fe3+ in solution can be calculated by measuring the relative magnitude of fluorescence intensity.

中文翻译：

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有序介孔二氧化硅包裹碳量子点及其在Fe3+检测中的应用

摘要 SiO2与碳量子点（CQDs）结合制备的纳米复合材料具有毒性低、荧光强度高、生物相容性好、水溶性好等优点，大大拓宽了其应用范围。然而，如果仅将SiO2和CQDs简单组合而没有进行任何结构设计，纳米复合材料的稳定性会很差，影响其实际应用价值。在这项工作中，我们首先通过简便的方法（30 分钟）在水溶液中快速合成有序介孔二氧化硅（OMS），然后通过水热法在 OMS 的介孔通道中原位生成 CQD，以获得 CQDs@OMS 荧光纳米复合材料。OMS 和 CQDs@OMS 的化学结构和形貌通过 FT-IR、XRD、SAXRD 和 TEM 进行表征，表明 CQDs 成功封装在 OMS 中。CQDs@OMS的稳定性测试结果表明，CQDs可以稳定存在于OMS的介孔通道中，CQDs@OMS纳米复合材料的荧光强度几乎与离子强度、pH值和储存时间无关。光学性能结果表明，CQDs@OMS纳米复合材料的最佳激发波长约为340 nm，发射波长约为440 nm。使用CQDs@OMS纳米复合材料作为荧光探针检测Fe3+，发现CQDs@OMS对Fe3+反应非常快。CQDs@OMS的荧光猝灭强度与Fe3+浓度在25-750 μM范围内具有良好的线性关系。因此，可以通过测量荧光强度的相对大小来计算溶液中微量的Fe3+。CQDs@OMS的稳定性测试结果表明CQDs可以稳定存在于OMS的介孔通道中，CQDs@OMS纳米复合材料的荧光强度几乎与离子强度、pH值和储存时间无关。光学性能结果表明，CQDs@OMS纳米复合材料的最佳激发波长约为340 nm，发射波长约为440 nm。使用CQDs@OMS纳米复合材料作为荧光探针检测Fe3+，发现CQDs@OMS对Fe3+反应非常快。CQDs@OMS的荧光猝灭强度与Fe3+浓度在25-750 μM范围内具有良好的线性关系。因此，可以通过测量荧光强度的相对大小来计算溶液中微量的Fe3+。CQDs@OMS的稳定性测试结果表明，CQDs可以稳定存在于OMS的介孔通道中，CQDs@OMS纳米复合材料的荧光强度几乎与离子强度、pH值和储存时间无关。光学性能结果表明，CQDs@OMS纳米复合材料的最佳激发波长约为340 nm，发射波长约为440 nm。使用CQDs@OMS纳米复合材料作为荧光探针检测Fe3+，发现CQDs@OMS对Fe3+反应非常快。CQDs@OMS的荧光猝灭强度与Fe3+浓度在25-750 μM范围内具有良好的线性关系。因此，可以通过测量荧光强度的相对大小来计算溶液中微量的Fe3+。