Alternating current-driven quantum-dot light-emitting diodes with planar architecture

Development of alternating current (AC)-driven devices with versatile architecture is a potential approach to realize multifunctional light-emitting sources. Planar AC-powered electroluminescent (pAC-EL) devices using lateral placement of electrodes, instead of conventional stacking, are an emerging design that manifests promising applications beyond displays. While phosphors and organic light-emitting materials have been applied in pAC-EL devices, further enhancing the color purity and brightness remains a daunting challenge. In this Letter, we explore the utilization of quantum dots as the emitting layer for pAC-EL single-insulation devices without external injection. In such architecture, light is produced by the recombination of internally generated holes and field-induced electrons in the emissive layer of two in-plane light-emitting units alternately. The developed pAC-QLEDs exhibited a maximum brightness of 2023, 6327, and 613 cd/m2 for red, green, and blue (RGB) emissions at 150 kHz, respectively. Furthermore, a white-emitting pAC-QLED and a bi-color pAC-QLED were also constructed by stacking the R/G/B QD layers in serial and putting the R/G QD layers in parallel, respectively. In addition, compatibility of the proposed device configuration with flexible substrates is also manifested. The development of pAC-QLEDs provides an effective route to achieve high brightness without external injection, indicating diverse applications of these light sources for health monitoring sensors and phototherapy.