Dynamic Response and Electroluminescent Performance of Organic Light-Emitting Diodes Driven by DC and AC Voltage

Abstract

This study investigates the dynamic response and electroluminescent performance of organic light-emitting diodes (OLEDs) driven with (DC+AC) devices, and the results were compared to those obtained for AC-driven OLEDs. The charge-carrier transit times and the mobilities were analyzed through frequency-dependent negative differential susceptance of the device. As the frequency increases for the AC-driven and (DC+AC) driven OLEDs, the capacitive effect of the device also increases. Thus, a phase difference occurs between the applied voltage and the current. The delay between the applied voltage and the electroluminescence is related to the charge-carrier transit time and recombination time. The charge-carrier transit time and the mobility were obtained by conducting an impedance analysis, and the electron transit time in this study followed the electric field-dependent Poole-Frenkel relation. The hole mobility was about 10 similar to 10(3) times higher than that for electrons, and this driving method is expected to reduce charge accumulation by providing a dynamic current to the device.