Nonlinear electro-thermal and light output modeling and simulation of OLEDs

Abstract

Lighting application of Organic Light Emitting Diodes (OLEDs) has been forecasted and such applications appear already in the high end segment of the market. These devices should provide homogeneous luminance – homogeneity is one of the quality metrics of such devices. Local light generation depends on both the local temperature and the local voltage drop across the light emitting polymer(s) in the device. Due to the large area of these devices the coupled optical, electrical and thermal simulation problem is of distributed nature. Electrical characteristics of organic semiconductor materials used in OLED devices are nonlinear, and their nonlinear temperature-dependence is significant. Measurement and temperature-dependent electrical and optical modeling of OLEDs is presented in this study. The paper addresses the special needs of OLEDs in distributed electro-thermal field simulation. These needs are not handled appropriately yet in the widely used, commercially available simulation tools. However the latest version of our SUNRED field solver algorithm is capable of handling these coupled, non-linear optical-electrical-thermal problems. The new features of the algorithm are demonstrated by modeling some research OLED samples available to us in the Fast2Light project – this way simulation results are compared against measured data. The results suggest that the models and the simulation tool can be used well in OLED design.