Fig. 1.

Photoluminescence of single GQDs. a Chemical structure of the C₉₆ and C₉₆Cl GQDs. R stands for C₁₂H₂₅. b Scheme of the microphotoluminescence setup. c 20 × 20 μm² PL map of the C₉₆ GQDs in polystyrene matrix. The color bar represents the number of counts per second on the APD. The scale bar is 3 μm. The zoom shows a diffraction limited spot that can be fitted with a 2D Gaussian function leading to a 1/e² diameter of ∼600 nm. The scale bar is 200 nm. d Room temperature PL spectra of a single C₉₆ GQD (solid line) and of a single C₉₆Cl GQD (dotted line). Polarization diagram in excitation (blue) and emission (red)