ELECTRO MODULATED PHOTO INDUCED ABSORPTION OF C-60 DOPED MEH-PPV

We have studied the field induced absorption (FIA) spectra of C-60 dop ed and undoped MEH-PPV films in the spectral range, (h) over bar omega (p), of 0.2 to 4 eV, with and without CW illumination with photon ener gy above the optical gap E-g. For (h) over bar omega(p) > E-g we measu red the electroabsorption (EA) spectrum of the doped material with and without illumination and compared it with that of the undoped materia l. For (h) over bar omega(p) < E-g the dominant effect is the field in duced modulation of the lifetime of the C-60:PPV charge transfer compl exes. This novel technique reveals three absorption bands at 0.4, 1.18 and 1.65 eV, which we assigned to bound pairs of C-60(-):PPV+ complex es.