Photoluminescence Studies on [C60] Fullerene Solutions in N-methyl-2-pyrrolidinone and Pyrrolidine

摘要

Photoluminescence (PL) spectra of C_(60) solutions in N-methyl-2-pyrrolidinone (NMP) show a drastic increase of the PL intensity if the solutions are stored longer periods of time. Two distinct spectral components, one in the red (1.92-2.00 eV) and another in the green (2.18-2.3 eV) were identified in the whole PL emission. Their weights depend on C_(60) concentration and on storage time. The two emissions come from two successive processes running with different kinetics. Charge transfer, leading to (C_(60),NMP) loose molecular complexes and a slow aggregation process of these entities seems to originate the red and green emission, respectively. Similar PL properties are found when pyrrolidine (P) is used, as solvent.