Coplanar electrodes color-tunable AC-OLEDs with wide operating windows

Alternating current-driven organic light-emitting diodes (AC-OLEDs) exhibit great potential for next-generation lighting and display applications owing to their advantage of direct integration into AC-based household electric systems, nevertheless, their low performance with high turn-on voltage and the inability of light emission in the entire cycle of AC signal remain major bottlenecks in their further development. Herein, the AC-OLEDs with coplanar electrodes (cpAC-OLED) are demonstrated, this new type AC-OLED architecture work in a broad voltage and frequency range, from 20 V/50 Hz to 200 V/10 kHz with low turn-on voltage and exhibits various optical feedback. The AC-OLEDs emit light in the whole cycle of applied AC signal, and manifest frequency-dependent color tunability. Moreover, these devices could be efficiently driven by a commonly used electric power supply (220 V/50 Hz, 110 V/50 Hz) without any additional back-end electronics. The working mechanism of developed cpAC-OLEDs based on a capacitor model is discussed. We anticipate that this work would accelerate the development of highly efficient color-tunable AC-driven lighting sources.