Luminescence spectroscopy of C 70 and C 70Ph 2 in crystalline toluene at 5 K

Abstract

Luminescence spectra for fullerene [70] with two phenyl groups covalently attached (C 70Ph 2) was recorded at room temperature and at low temperature in a crystalline toluene matrix. Finely resolved luminescence spectra (Shpol'skii effect) are observed at 5 K under excitation at 514 nm. We assign an intense line at 780.2 nm as the origin band of the S 1–S 0 transition. By comparison with the fluorescence spectrum of C 70 in toluene at 5 K, two other bands located at shorter wavelength are tentatively identified as the origin lines of the S 2–S 0 and S 3–S 0 transitions. It results from these assignments that the effect of adding two phenyl groups to the fullerene cage produces a 116.3 nm red-shift of the fluorescence of C 70Ph 2 as compared with the fluorescence in C 70.