We study the photoluminescence (PL) and the PL dynamics of Ir(PPY)3-doped poly(N-vinylcarbazol) (PVK)under the modulation of an electric field. The results show that the electric-field-induced quenching of PL from Ir(PPY)3-doped PVK mainly comes from the dissociation of excitons in the chains of P VK. There is no significant difference in the excited state lifetime of Ir(PPY)3 to be observed under the different applied negative biases.Our experiments demonstrate that the excitons attached to the molecules of Ir(PPY)3 are very stable.