Shadow Mask-Based RGB Color Patterning in QLED Panels via Selective Quenching by Metals.

High-resolution color patterning of Quantum Dot Light-Emitting Devices (QLEDs) remains a challenge, since solution-based methods lack the resolution for subpixel patterning and other strategies often reduce scalability or device performance. In this work, we introduce and present results from a new shadow mask-based RGB color-patterning approach for QLED panels. This approach uses very thin metal layers, only 1-2 nm thick, that can be readily deposited through shadow masks to selectively quench luminescence from areas of a tandem stack containing multiple QD layers, enabling different regions of the stack to emit different colors when bias is applied. Photoluminescence, optical transmittance, and topographic measurements are used to study the effect of depositing ultrathin metal layers on the luminescence properties of QD films. Results from red- and green-emitting QLEDs formed side by side on the same substrate using this approach are presented, demonstrating its feasibility for color patterning. Because the patterning is realized through thermal evaporation of metals using shadow masks, the approach is inherently compatible with established fine metal mask (FMM) RGB patterning processes used in OLED manufacturing, indicating that pixel resolutions similar to those of OLED displays can be readily obtained in QLED displays without necessitating alternative patterning strategies.