Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
University of Science and Technology of China, Hefei 230026, China.
J Phys Chem Lett. 2022 Jun 2;13(21):4768-4777. doi: 10.1021/acs.jpclett.2c01161. Epub 2022 May 25.
Carbon quantum dots (CDs) with favorable fluorescent properties have stimulated considerable effort to modulate their photoluminescence (PL) for bioimaging and sensing. However, the fluorescent mechanisms are still only partially understood due to the diverse physicochemical properties of CDs prepared by various synthesis methods and postpreparation processes. In this report, pressure-induced bifurcation of PL is reported in red carbon quantum dots (R-CDs) for the first time. The splitting of PL into an irreversible blue-shifted peak and a reversible red-shifted peak under pressure suggests the coexistence of multiple fluorescent mechanisms in R-CDs, i.e., emissions from surface groups and nitrogen-doped cores. The concentration and excitation laser energy dependencies of pressure-induced bifurcation, as well as the time-resolved PL, further support the coexistence of multiple emitters. Our results provide a method for distinguishing between the different fluorescent mechanisms related to surface groups and carbon cores in CDs.
碳量子点（CDs）具有良好的荧光性质，这激发了人们相当大的努力来调节它们的光致发光（PL），以用于生物成像和传感。然而，由于通过各种合成方法和后处理过程制备的 CDs 具有不同的物理化学性质，其荧光机制仍仅部分被理解。在本报告中，首次报道了红色碳量子点（R-CDs）中压力诱导的 PL 分叉。PL 在压力下分裂为不可逆的蓝移峰和可逆的红移峰，表明 R-CDs 中存在多种荧光机制，即来自表面基团和氮掺杂核的发射。压力诱导分叉的浓度和激发激光能量依赖性以及时间分辨 PL 进一步支持了多个发射器的共存。我们的结果为区分与 CDs 中表面基团和碳核相关的不同荧光机制提供了一种方法。
