This document analyzes the effect of increasing the work function of the anode material on the performance of organic light-emitting diodes (OLEDs). Two OLEDs are designed and simulated using different anode materials: indium tin oxide (ITO) and zinc oxide (ZnO). The results show that using ZnO, which has a higher work function than ITO, increases the anode current, luminance power, and recombination rate in the organic layer. Increasing the anode work function improves device performance by increasing the built-in potential and thus charge injection and recombination in the OLED.