Quantum-dot and organic hybrid light-emitting diodes employing a blue common layer for simple fabrication of full-color displays

Colloidal quantum-dot (QD) light-emitting diodes (QLEDs) have been in the forefront of future display devices due to their outstanding optoelectronic properties. However, a complicated solution-process for patterning the red, green, and blue QDs deteriorates the QLED performance and limits the resolution of full-color displays. Herein, we report a novel concept of QD–organic hybrid light-emitting diodes by introducing an organic blue common layer (BCL) which is deposited through a common mask over the entire sub-pixels. Benefitted from the optimized device structure, red and green QLEDs retained their color coordinates despite the presence of the BCL. Furthermore, adopting the BCL improved the external quantum efficiency of green and red QLEDs by 38.4% and 11.7%, respectively, due to the Förster resonance energy transfer from the BCL to the adjacent QD layers. With the BCL structure, we could simply demonstrate a full-color QD–organic hybrid device in a single substrate. We believe that this device architecture is practically applicable for easier fabrication of solution-processed, high-resolution, and full-color displays with reduced process steps.