Red quantum-dot common layer for organic-quantum-dot hybrid light-emitting diodes for full-color displays

Abstract

Organic and quantum dot (QD) light-emitting diodes (OLEDs and QLEDs, respectively) have been known for their practical application in full-color displays. Each primary color-emitting layer (EML) needs to be patterned via fine metal shadow masks (FMMs) or inkjet printing. However, the FMM method suffers from a shadow effect, misalignment, and size limitation, while inkjet printing hinders fine patterning, which disrupts high-resolution, large-scale fabrication. Here, we show a novel organic–QD hybrid device architecture by introducing a red QD common layer (QDCL). Since the QDCL is deposited onto all sub-pixels in a solution process without patterning, one patterning step for the red sub-pixel is reduced for full-color display fabrication. The green and blue OLEDs incorporating a red-emitting QDCL emitted their own color, owing to the effective exciton confinement within the EML by adopting a buffer layer, while the QDs in the QDCL emitted saturated red light. As a result, we could demonstrate a full-color organic–QD hybrid light-emitting device fabricated on a single substrate using the QDCL. We believe our strategy would help fabricate full-color and high-resolution displays with reduced manufacturing costs and time.