Spectroscopical evidences of photoinduced charge transfer in blends of C-60 and thiophene-based copolymers with a tunable energy gap

We report a study of the photoinduced charge transfer in the blends of buck minsterfullerene (C-60) and thiophene-based copolymers with tunable energy gap. The photolumiescence and steady state photoinduced absorption spectra evidence the electron transfer from the photoexcited copolymer to C-60 The efficiency of the charge transfer depends on the degree of miscibility of t he two components which is easily controlled by the copolymer composition. In the blends obtained with a copolymer with an high energy absorption onse t, the spectral signatures of the photoinduced hole transfer to the polymer , arising from the selective excitation of the Coo, are also detected. (C) 2001 Elsevier Science B.V. All rights reserved.