Abstract
Ferntosecond electric-field assisted pump-probe measurements were performed on organic light-emitting devices based on poly(9,9-dioctylfluorene). The dynamics of polarons generation, due to field induced singlet dissociation, and recombination into triplet and singlet states are investigated. The efficiency of polarons recombination into singlet states was found to be around 70%. Carriers mobility at the microscopic scale was found to be mu(t)= 1-10(-2) cm(2)/Vs indicating the presence of a dispersive and hot transport.