▎ 摘　　要

We have reinvestigated the optical spectroscopy of C132 graphene quantum dots by absorption, selective fluorescence, excitation and time-resolved spectroscopy, the external heavy atom effect, and DFT based quantum chemical calculations. In particular, wavelength-selective photobleaching provides strong evidence for the assignment of the intrinsic absorption and emission features of the quantum dots and indicates that emissions observed at similar to 670 and similar to 630 nm and associated relatively narrow features that display vibrational progressions in the selective excitation spectra are due to different species. The emitting state that leads to a broad emission (1700 cm(-1)) centered around 750 nm appears to be a "near-dark" singlet state with a relatively long lifetime of similar to 30 ns. Simulated spectra, based on the nuclear ensemble approach, are in qualitative agreement with this finding and indicate very low oscillator strengths with some significant electron-vibrational intensity borrowing.