Accurate analysis of 10 nm emission zone features in OLED

Adjusting the emission zone (EMZ) is crucial for optimizing the efficiency and operation lifetime of active electroluminescent devices such as organic light-emitting diodes (OLEDs). Measuring EMZ details from OLED radiation patterns is challenging due to the thin active layer (thickness ~10 nm) and the resulting limited accessibility of the emission zone features, which complicates the comparability of different mathematical models. We use a polynomial description to estimate practical limits for resolving EMZ details. The normalization of the polynomial description leaves only two free parameters characterizing an EMZ. This allows tracking EMZ shifts, defining accessible optimization targets, and designing the OLED stack for emission zone analysis properly. The presentation will introduce the resolution limit and the visualization concept in a two-dimensional plane and illustrate practical applications, experimental procedures, and current dependent EMZ shifts.