Luminescence of carbon quantum dots in amorphous carbon

Subject of study. The luminescence spectrum of amorphous protonated carbon (a-C:H) containing carbon quantum dots is studied. Aim of study. How the peak in the luminescence spectrum of a-C:H is affected by the presence of fragments with different configurations is determined. Method. The typical spectra are compared against those of the closest analogs: polycyclic aromatic hydrocarbons with a small number of aromatic rings. Main results. Bright blue fluorescence due to the presence of an ensemble of graphene islands embedded in a diamond-like matrix is experimentally observed in a-C:H [Opt. Express 19, 17935 (2011)] and similar materials. The experimental spectrum appears consistent with a theoretical spectrum generated by superposing the non-uniformly broadened spectra of three analogs, namely, acenaphthylene, pyrene, and azulene (with each spectrum being assigned different weights). This research can be generalized to a wider range of carbon materials that fluoresce at short wavelengths. Practical significance. The results from this study of the properties of carbon quantum dots in amorphous carbon can be used to develop materials for conversion of ultraviolet electromagnetic radiation into visible light. (c) 2024 Optica Publishing Group