Photophysical Properties of Fullerenes Prepared in an Atmosphere of Pyrrole

• Published in: Chemistry of materials 1994-10, Vol.6 (10), p.1850-1853
• Main Authors: Glenis, S, Cooke, S, Chen, X, Labes, M. M
• Format: Article
• Language: English
• Subjects: 400500 - Photochemistry; ABSORPTION SPECTROSCOPY; Atomic and molecular clusters; Atomic and molecular physics; AZOLES; CARBON; CHEMICAL PREPARATION; CHEMISTRY; CHROMATOGRAPHY; ELEMENTS; EMISSION SPECTROSCOPY; Exact sciences and technology; FLUORESCENCE SPECTROSCOPY; FULLERENES; HETEROCYCLIC COMPOUNDS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LIQUID COLUMN CHROMATOGRAPHY; MASS SPECTROSCOPY; NITROGEN COMPOUNDS; NONMETALS; Optical properties of clusters; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHOTOCHEMISTRY; Physics; PYRROLES; SEPARATION PROCESSES; SPECTROSCOPY; Spectroscopy and geometrical structure of clusters; Studies of special atoms, molecules and their ions; clusters; SYNTHESIS
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm00046a046

Samples of C[sub 60] and C[sub 70] containing a variety of nitrogen-doped species were prepared by arc vaporization of graphite in the presence of pyrrole. Cage-doped fractions were isolated by column chromatography and characterized by mass spectroscopy, optical absorption, and fluorescence measurements. Mass spectra were consistent with the substitution of an even number of carbon atoms of the C[sub 60] and C[sub 70] cages by nitrogen atoms. Carbonaceous clusters including fragmented fullerenes containing hydrogen atoms were also formed. UV-visible spectral analysis indicated that there is an influence of the molecular weight on the fundamental [pi]-[pi]* electronic transition. Fluorescence spectra showed a broad band containing vibrational fine structure that is attributed to photoseparated charges in the fragmented fullerenes and a shoulder on the low-energy side that is related to intrinsic excitation in the nitrogen-doped species. Fluorescence results imply a bandgap of 2.36 eV for the N doped fullerenes and the existence of intermediate excitonic transitions below the optical bandgap. Although it has not yet been possible to isolate a pure cage-doped material, the photophysical studies add credence to their existence and the importance of further attempts at their isolation. 17 refs., 4 figs., 1 tab.