Process window single layer OLED
When you produce your OLED your deposition tool naturally introduces experimental errors in e.g. the layer thicknesses. Depending on your OLED setup even small thickness changes can dramatically influence the performance of your OLED. With SimOLED you can quickly find out how sensitive your OLED key figures react to changes of e.g. layer thickness. With SimOLED's automatic parameter variation you can apply up to three thickness variations simultaneously to identify the best process window for your device. The following example compares the luminance for a single layer OLED in bottom emission and top emission configuration.
Simulated luminance as a function of observation angle and emitter layer thickness (click to enlarge). Left: bottom emission (anode=ITO, cathode=LiF-Al), right: top emission (anode=Ag, cathode=Ag).
From the results you can easily see that your process window for the bottom emission configuration is much larger (+/- 10% of optimal thickness value is still ok) than for the top emission case where you should not allow more than ~5 % thickness error.
Optimal working point for white OLED
SimOLED's automatic parameter variation feature can also be used to identify optimal working points. The following example varies the thickness of the hole and electron transport layer simultaneously to find the thickness combinations which yield the largest luminous flux and to identify the process window for these combinations.
Setup for the white OLED used (only module OPTIC enabled)
Total luminous flux as a function of HTM and ETM.
For this device you can easily identify two optimal configurations at (45;40) and (10;40) nm layer thickness of HTM and ETM, respectively. These layer thicknesses will yield the most light output. Additionally, you also see how much experimental thickness error you can allow in order to still be within the optimal process window.