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-film light-emitting diode (LED) structures made from blends of poly(phenyl-p-phenylene vinylene) and polycarbonate. The dependence of fluorescence quenching on excitation wavelength, electric field and concentration has been measured. Efficient fluorescence quenching is observed, which is attributed to field-induced dissociation of excitons. The same effect is expected to be operative in LED devices limiting electroluminescence quantum yield. An estimate of the exciton binding energy of EB ≈ 0.4 eV in this class of system is inferred from the field dependence by comparison with model calculations.