State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
Nanoscale. 2019 May 16;11(19):9526-9532. doi: 10.1039/c9nr01118h.
Fluorescent materials can be powerful contrast agents in photoelectric devices and for bioimaging. As emerging fluorescent materials, carbonized polymer dots (CPDs) with high quantum yields (QYs), long-wavelength emission and multiple functions are highly desired. Despite great progress in the synthetic methods and QYs of CPDs, multiple emission of CPDs is challenging. Therefore, we developed CPDs with dual-emission fluorescence in terms of inherent blue and red emission. In addition, CPDs with sole blue emission (B-CPDs) and red emission (R-CPDs) were synthesized, respectively, by regulating the reaction conditions to control the quantitative structure and emission centers. The absolute QY of R-CPDs in water was 24.33%. These three types of CPDs with dual/sole emission could be used in optoelectronic and bioimaging applications. With different CPDs coated on a commercially available gallium nitride light-emitting diode chip as a color-conversion layer, LEDs with blue, yellow, and red emission were achieved. Benefiting from the different emission intensities and emission peaks of R/B-CPDs in different pH conditions, they were used (without further modification) to distinguish between Porphyromonas gingivalis, Streptococcus mutans, Escherichia coli and Staphylococcus aureus in dental plaque biofilms (the first time this has been demonstrated). These findings could enable a new development direction of CPDs based on the design of multi-emission centers.
荧光材料在光电设备和生物成像中可以作为强大的对比剂。作为新兴的荧光材料，具有高光量子产率（QY）、长波长发射和多功能的碳化聚合物点（CPD）备受期待。尽管在 CPD 的合成方法和 QY 方面取得了很大进展，但 CPD 的多色发射仍然具有挑战性。因此，我们开发了具有固有蓝、红双发射荧光的 CPD。此外，通过调节反应条件分别合成了具有单一蓝色发射（B-CPDs）和红色发射（R-CPDs）的 CPD，以控制定量结构和发射中心。R-CPD 在水中的绝对 QY 为 24.33%。这三种具有双/单发射的 CPD 可用于光电和生物成像应用。将不同的 CPD 涂覆在市售的氮化镓发光二极管芯片上作为颜色转换层，实现了具有蓝色、黄色和红色发射的 LED。由于 R/B-CPD 在不同 pH 条件下的发射强度和发射峰不同，它们（无需进一步修饰）可用于区分牙菌斑生物膜中的牙龈卟啉单胞菌、变形链球菌、大肠杆菌和金黄色葡萄球菌（首次证明）。这些发现可以为基于多发射中心设计的 CPD 开辟新的发展方向。
