Nitrogen-doped carbonized polymer dots activated by alkalinity of arginine for multicolor multi-platform sensor

Among carbon-based materials, carbon dots (CDs) are popular because of their stable optical properties and good biocompatibility. Their fluorescence properties often are tailored by size, surface modification, or heteroatom doping with multiple precursors. In this paper, the alkalinity of Arginine (Arg) acts as an activator to promote carbonation and increase luminescence efficiency. Meanwhile, Arg acts as a tetrahedron and plays another three roles in preparing amino-modified nitrogen-doped carbonized polymer dots (SA-NCPDs), in which Arg serves as carbon source, nitrogen-doped nitrogen source, and surface modifier. The NCPDs based only on arginine display narrow full width at half maximum (FWHM) of 54 nm. The SA-NCPDs present dual emission distribution in the UV and visible blue regions, respectively. The SA-NCPDs present multicolor emission, especially crimson emission in water under 77 K in different solvents. Besides, SA-NCPDs in different solvents and the prepared polyvinyl alcohol (PVA) composite film have different phosphorescence and long afterglow at 77 K. The excellent biocompatibility and stability of the SA-NCPDs imply it is a potential material in biomedicine. In addition, a multiplatform multicolor ratiometric sensor and visualized colorimetric sensor with high selectivity were constructed successfully for detecting Cu²⁺, H₂O_2, and OPD based on self-absorption.