U.S. 4,742,109 PBT compositions

Abstract

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.