Investigation of luminescent mechanism: N-rich corbon dots as the luminescence center of fluorescent Hydroxyapatite prepared by a typical hydrothermal process
As no toxic metal ions or photobleaching fluorescent organic dyes involved, the defect-related fluorescent HAp materials are expected to be excellent fluorescent probes in biological field. The lack of in-depth understanding of the luminescent mechanism makes it difficult to adjust their emission performance for better application in bio-imaging. In this study, a novel luminescent mechanism of defect-related HAp fluorescent materials obtained from the typical hydrothermal route was revealed. N-rich carbon dots (CDs) instead of the reported CO ˉ was confirmed to be the luminescence center and responsible for the self-activated luminescence. The combining way between N-rich CDs and the HAp host might be the CDs (mainly its polymer clusters and/or molecular fluorophores constituents) trapped in the HAp crystal structure. This study gave inspiration to the design of fluorescent HAp with a tunable fluorescence emission due to the diverse synthesis methods and tunable fluorescence emission of CDs.