Color Purity Enhancement of Green Quantum Dot Light-Emitting Diodes Using the Blue Light Absorber Packaging Structure

Quantum dots (QDs) have broad application prospects in display such as full color light-emitting diode (LED) devices due to their narrow emission half-peak width and high quantum yield. However, an ultra-high concentration of QD is required to eliminate the pumping light (typical blue light with short wavelength) for achieving high color purity, leading to significant reduction in the optical power of QDs. In this paper, we have introduced the blue light absorber (BLA) in green quantum dot-light emitting diodes (GQD-LEDs) to adjust the color coordinates. Results indicate that the increase of the QD concentration can eliminate the blue light and increase the color purity, while it simultaneously decreases of the optical power of QDs owing the reabsorption loss. The BLA layer has high absorption for short-wavelength light (less than 460 nm), which greatly reduces the optical power of blue light by 74% and leads to a large shift in the color coordinates from (0.17, 0.22) to (0.18, 0.47). Moreover, the BLA layer has a high transmittance for the long-wavelength light, thereby ensuring a high green optical power for BLA devices. Consequently, the proposed method has great potential for the future application of QD-LED in full color display.