Carbon dots with aggregation induced emission enhancement for visual permittivity detection.

Photoluminescent carbon dots (CDs), hydrothermally prepared using tannic acid (TA), show visual aggregation induced emission enhancement (AIEE) properties at 455 nm when excited at 350 nm owing to the rotational hindering of the surface groups on CDs such as aromatic rings and phenolic hydroxyl ones, causing exponential decay between the ratio of the photoluminescence intensity in organic solvents to that in water and the permittivity of the solvent, and thus dazzling emissions of the CDs in the presence of solvents with small permittivity, tetrahydrofuran (THF), for instance, could be visually observed.