Analysis of electroluminescence degradation for organic light-emitting diode using a rate equation of chemical kinetics

Light intensity degradation is one of the most important parameters in the design of organic light-emitting diodes (OLEDs) for image applications, and it is usually obtained through time-consuming stability tests. The lifetimes are estimated based on the well-known empirical reciprocal relationship between the initial brightness and the half-lifetime, which is assumed to be always valid for all devices. In this work, it was used as a chemical kinetics approach for modeling the light output in time under constant current operation. Through this approach, an equation with only two parameters, one for OLED light output in time and another for half-lifetimes, was obtained. This approach was applied to stability tests for three different OLEDs to determine how their features affect the kinetic parameters and to compare such parameters for OLEDs operating at two temperatures, 22°C and 70°C, to determine if they have a correlation with thermal stability.