ELECTRIC-FIELD-INDUCED PHOTOLUMINESCENCE QUENCHING IN THIN-FILM LIGHT-EMITTING-DIODES BASED ON POLY(PHENYL-P-PHENYLENE VINYLENE)

We report on electric field-induced fluorescence quenching in thin-fil m light-emitting diode (LED) structures made from blends of poly(pheny l-p-phenylene vinylene) and polycarbonate. The dependence of fluoresce nce quenching on excitation wavelength, electric field and concentrati on has been measured. Efficient fluorescence quenching is observed, wh ich is attributed to field-induced dissociation of excitons. The same effect is expected to be operative in LED devices limiting electrolumi nescence quantum yield. An estimate of the exciton binding energy of E (B) approximate to 0.4 eV in this class of system is inferred from the field dependence by comparison with model calculations.