中文摘要：

聚合物碳纳米点是近年来新兴的一种荧光纳米探针,具有较低的生物毒性、良好的水溶性、较高的量子产率、优异的光/化学稳定性以及良好的生物相容性.目前所制备的碳点大都表现出蓝、绿色荧光发射.为实现碳点长波荧光发射,扩大其在生物标记与成像及光电显示方面的应用,本文采用水相一步法交联聚合反应制备了具有橙红荧光发射性质且具有双光子效应的聚合物碳点,发射波长为604 nm,荧光量子产率达到30.64%,并且应用在生物活体成像中.

英文摘要：

Polymer carbon nano dots（PCNDs） have recently emerged as important nanomaterials. Although they have many attractive luminescence properties, most of them show intense emissions at short blue or green wavelengths. In this work, we designed a facile, high-output method for fabricating orange-red emissive PCNDs（centered at 604 nm, PLQY 30.64%） with two-photon fluorescence. The PCNDs were no crystal lattice polymer dots with an average diameter of 20 nm, which were detected by TEM and HRTEM. And the XPS findings indicated that C=O and graphitic N play important roles in the red emission. UV-Vis absorption spectrum of PCNDs exhibited several absorption maxima/bands at 277, 386, 541 and 575 nm（though the absorption at 541 and 575 nm was very weak）, and a maximum emission wavelength of 600 nm with excitation-wavelengthindependent PL. At lower temperatures, dopamine and o-phenylenediamine underwent a dehydration reaction to form intertwined polymer chains with benzene rings and heterocycles in the backbone. Inside the PCNDs, large molecules or crosslinked polymer chains were dominant rather than carbonized structures. The PL mechanisms of the PCNDs were mainly molecule state emission or crosslink-enhanced emission. Moreover, the QY of the PCNDs was 30.64%, which was the highest value recorded for red emissive CNDs. To assess the prospects of the PCNDs as a bioimaging material, KB human oral squamous carcinoma cells were used to evaluate the cytocompatibility of the PCNDs. The cell viability of the PCNDs was determined by a methyl thiazole terazolium（MTT） assay. The MTT assays of cell viability studies suggested that the PCNDs demonstrated low cytotoxicity and were not found to pose any significant toxic effects. This result concluded that PCNDs can be used in a high concentration for imaging or other biomedical applications. Then, the luminescence stability of these PCNDs was examined by irradiating with a UV lamp for 8 h. The results turned out that almost no PL attenuation was observed. For bioimaging,