Color-Tunable Alternating-Current Quantum Dot Light-Emitting Devices

To date, it remains a central challenge to achieve electroluminescence in both positive and negative half cycles of alternating-current (AC) voltage for a light-emitting device. Herein, we successfully demonstrated a novel structure to construct a real AC quantum dot light-emitting device (QLED) with two charge generation layers (CGLs) consisting of the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ZnO nanoparticle bilayer structure. Besides the conventional driving way with power input from a pair of opposite electrodes, this AC QLED can also work in the manner of in-planar-electrode driving mode, achieving simultaneous electroluminescence of each pixel. By employing a bilayer emissive layer composed of red and green quantum dots, the emission color of the AC QLED can be tuned by both the polarity and amplitude of the driving voltage. Leveraging the excellent electron injection and negligible voltage consumption from the CGLs, this QLED can be turned on at a record low voltage of 5.6 V. We believe that this AC QLED can provide a platform for the realization of simple and smart plug-and-play QLED-based display and lighting systems.