In this work a NIR emitting dye, p-Toluenesulfonate (IR-813) was explored as a model precursor to develop red emissive carbon dots (R-CD) for fluorescent imaging. Current commercial photosensitizers (PS) used in fluorescence-based techniques have glaring limitations. For example, to achieve optimal efficiency, PS used in theranostics techniques require the utilization of light within the red region to NIR-I window ranging between 650-950 nm, respectively. A direct consequence of this requirement typically results in the degradation of the PS such as photobleaching or thermal degradation. Additionally, modern PS have the disadvantage of non-rapid blood clearance from the host which limits biomedical applications. Significantly, (CDs) have attracted increasing attention in various biomedical areas of application such as in vitro/in vivo imaging, photodynamic and photothermal therapy. Previous literature suggests that complex surface modifications of produced CDs with hydrophobic organic dyes as the precursor are of interest to unlock the potential route to develop red emissive CDs. If one were to develop carbon dots (CDs) from this source, it is expected that the product will retain most of the functionality of the precursor. In this case, mainly utilization in the far-red region between 700 – 900 nm respectively.
