Simulation on Current–Voltage Characteristics and Aging Analysis of Organic Light‐Emitting Diode with Heterojunction Using Equivalent Circuit Model

An equivalent circuit model for organic light‐emitting diodes (OLEDs) with heterojunction is established, and the current ( I )–voltage ( V ) relationship of OLED is investigated using the model. The evolution of I–V characteristics is prolonged from traditional three regions to four regions from the model, which are leakage, recombination, transition, and high‐operating regions. This four‐region model well matches the measured electrical performance of OLED, and the variations in resistances and voltages of OLED under aging are successfully analyzed through the model. The simulated results of OLEDs under different aging degrees are well consistent with the measured results, with the average deviation value of only 1.23% and the maximum deviation value of 4.18%. Moreover, by fitting the parameters of the equivalent model under different aging conditions, the I – V characteristics of OLEDs under longer aging time can be predicted. This model can be used to analyze the electrical performance of OLEDs and estimate their aging rate, which aids in the design of compensation circuits for practical applications.