The oxygen states (O-states) of carbon quantum dots (CDs) play an important role, with regard to their optical properties and analytical applications. However, the rapid screening of O-states in CDs is still a great challenge, because of the complicated surface composition. In this study, it is found that the chemiluminescence (CL) intensity of prepared CDs in the presence of peroxynitrite (ONOO^–) is proportional to the content of C–O group-related O-states. The related mechanism discloses that the O-state-dependent CL is due to the fact that abundant C–O functional groups in CDs with high O-states could facilitate the electron transfer of the produced smaller energy gaps for strong CL emission. Hence, ONOO^–-induced CL can be utilized as a facile probe for the rapid screening of O-states in CDs with some advantages, such as rapid response, low cost, and easy operation. Its practicability is verified by detecting the CL of phosphorus-doped CDs with variable phosphorus-doping contents. The content of C–O group-related O-states in sulfur-/phosphorus-doped CDs measured by the proposed CL probe is consistent with X-ray photoelectron spectroscopy (XPS) characterization. This strategy can also be extended to distinguish O-states in different types of nanoparticles by tuning the CL probe molecules.

中文翻译：

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化学发光探针快速筛选碳量子点中的氧态

就其光学性质和分析应用而言，碳量子点（CD）的氧态（O-态）起着重要作用。然而，由于表面组成复杂，快速筛选CD中O态仍然是一个巨大的挑战。在这项研究中，发现在过氧亚硝酸盐（ONOO ^–）存在下，制备的CD的化学发光（CL）强度与C–O基团相关O态的含量成正比。相关机理揭示了依赖于O态的CL是由于以下事实：具有高O态的CD中丰富的C–O官能团可以促进产生的较小能隙的电子转移，从而实现强CL发射。因此，ONOO ^–诱导的CL可以用作快速筛选CD中O态的简便探针，具有一些优点，例如响应速度快，成本低和易于操作。通过检测含磷量可变的掺磷CD的CL来验证其实用性。所提出的CL探针测量的硫/磷掺杂CD中C–O基相关O态的含量与X射线光电子能谱（XPS）表征一致。通过调整CL探针分子，也可以扩展该策略以区分不同类型纳米粒子中的O状态。