Inkjet-printed full-color tandem quantum dot light-emitting diode with dual-color subpixels

초록

This study reports a full-color alternating-current (AC) tandem quantum-dot light-emitting diode (QLED) architecture based on a two-subpixel design, fabricated using an inkjet printing process. Unlike conventional displays that horizontally arrange red, green, and blue subpixels, the proposed system achieves full-color representation using only two types of color-tunable subpixels (R-B and G-B) that emit specific colors depending on the voltage polarity. The device features a vertically symmetric tandem structure with an intermediate connecting layer (ICL) sandwiched between two stacked emissive layers (EMLs). Facilitated by a Zener-breakdownassisted charge generation mechanism, the bottom EML emits under negative bias, while the top EML emits under positive bias. When an AC signal of 60 Hz or higher is applied, the human eye perceives a blended color through temporal color mixing. To ensure high-quality patterning, a binary solvent system was optimized to suppress the coffee-ring effect and achieve uniform thin films during inkjet printing. The resulting devices achieved a wide color gamut of 115.4% (DCI-P3). Notably, by designing a relatively larger blue emission area, this architecture is expected to mitigate the stability and short-lifetime issues typically associated with blue emitters. This technology presents an innovative direction for enhancing pixel density and simplifying fabrication processes for high-resolution micro-displays and next-generation self-emissive displays.

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