Thin-film electroluminescent devices excited by a linearly rising voltage

The average and instantaneous luminances of a thin-film electroluminescent device (TFELD) are determined as functions of the voltage rise time by solving kinetic equations for the concentration of excited emission centers in the electroluminescent layer of the device. It is shown theoretically and experimentally that the dependences of the average and peak luminances, the external and internal quantum yield, the energy yield, and the luminous efficacy as functions of the voltage rise time all have a maximum, and the position of that maximum depends on the frequency of the driving voltage. The calculated and experimental dependences make it possible to determine the main parameters of the electroluminescence process: the collisional excitation cross section for the emission centers, the concentration of emission centers, and the transition probability of the emission centers to an excited state, as well as the radiative and nonradiative recombination probabilities of these and other centers. Zh. Tekh. Fiz. 69, 58–63 (February 1999)