One-step synthesis of N, P Co-doped orange carbon quantum dots with novel optical properties for bio-imaging

Chemical doping with heteroatoms can modulate physicochemical and photochemical properties of carbon dots (CDs). However, the development of multi heteroatoms co-doped CDs is still in early stage. In this work, a facile solvothermal synthesis strategy was applied to prepare multi heteroatoms (nitrogen and phosphorus) codoped carbon dots (N, P-CDs) using formamide and phosphoric acid as nitrogen source and phosphorus source, respectively. Compared with other CDs, the multi heteroatoms lead to dramatic improvement in the electronic characteristics and surface states. Thus, as the change of excitation wavelength, exciton recombination at different energy levels can be achieved, exhibiting the tunable luminescence from blue to orange regions. The prepared carbon dots have excitation dependence in the blue region, excitation independence in the orange region and high fluorescence stability. Its' quantum yield (QY) is up to 47%. Plus, N, P-CDs is non-toxic to cells and can be used in cell imaging, which indicates carbon dots can be a potentially excellent bioimaging probe.

Automated summary

In this study, nitrogen and phosphorus co-doped carbon dots were prepared using a solvothermal synthesis strategy, resulting in improved electronic properties and tunable luminescence. The prepared carbon dots showed excitation-dependent emission in the blue region and excitation-independent emission in the orange region, with a high quantum yield of 47%. The N, P-CDs were found to be non-toxic to cells and suitable for cell imaging applications, suggesting their potential as excellent bioimaging probes.