Time dependence of current density, luminance, and efficiency under dc voltages for the thin-film electroluminescent device containing praseodymium and aluminum co-doped perovskite titanate phosphor

Time dependence of current density, luminance, and efficiency under dc voltages were measured for the thin-film electroluminescent device containing (Ca0.6Sr0.4)0.998Pr0.002Ti0.9Al0.1O3−δ phosphor in order to understand the electroluminescence mechanism. The current density was not zero and the luminance was close to zero immediately after voltages were applied to the device. Then, the current density and the luminance increased, reached a maximum, and decreased. The luminance and the efficiency did not recovered at room temperature but recovered at 400 °C. We proposed the band structures of the device depending on time due to electromigration of oxygen vacancies.