Investigation and optimization of the charge generation layer (CGL) in tandem OLEDs using Taguchi’s orthogonal arrays and nondestructive capacitance-voltage (C-V) measurements

In this study, we utilize a simple, reliable Taguchi’s orthogonal array to optimize a tandem organic light-emitting diode (OLED). Furthermore, we use a capacitance-voltage (C-V) measurement to verify the charge generation layer (CGL) performance and make tandem OLED performance predictions. We demonstrate that Taguchi’s orthogonal array works correctly. In addition, it was determined that C-V measurement is a reliable way to resolve the CGL mechanisms and predict OLED efficiency directly. Based on the experimental results, it was proven that using the Taguchi’s orthogonal array improved the efficiency of the tandem OLED device. The current efficiency increased from 3.56 cd/A to 6.13 cd/A. The results of the C-V measurement were compared with the Taguchi’s orthogonal array, and the performance of the device was analyzed based on changes in the trend of the capacitance value. These two methods can be used together to achieve reliable optimization results with a limited number of experiments.