Current Density-Voltage Characteristics of AC Thin-Film Electroluminescent Devices with Different Dielectric-Phosphor Interfaces

Abstract

Four kinds of AC thin-film electroluminescent devices constructed with different insulating layers were prepared to study the I-V characteristics. In this study, we evaluated the I-V characteristics from the charge density-voltage (Q-V) characteristics which are measured using a Sawyer-Tower circuit and a simple series capacitor model. The results of these two methods are very similar to each other. From the I-V characteristics of these samples, a simple conclusion can be drawn: the sample with higher brightness and efficiency has higher current density. The relationships between brightness and transferred charge (B-Q), brightness per unit transferred charge and transferred charge (B/Q-Q), and the differential value of ΔB/ΔQ and transferred charge (ΔB/ΔQ-Q) of these samples have been discussed. From these results, we can conclude that the interface between the low-resistivity insulating layer and the active layer can provide the more efficient electrons for exciting the luminous centers.