A similar statement has been reported by Choi and Kim, who determined that the suppression of electron-induced degradation played a pivotal role in enhancing operational stability . In the exciplex-based devices, compared to the voltage increase in HODs, the growth was more pronounced in EODs (Fig. and). Taking advantage of the isotope effect, the voltage increase was reduced from 1.07 V for non-deuterated exciplex to 0.49 V for deuterated exciplex, indicating an effective route to inhibit electron-induced degradation processes. These outcomes suggest an objective enhancement of the polaron stability for exciplex-forming host materials.