Single‐Pixel Color‐Tunable QLEDs Based on Solution‐Processed Stacked P–i–n–i–p Heterostructures and Their Potential Applications for High‐Resolution Displays

ABSTRACT

To achieve high pixel density displays, a color tunable quantum dot light‐emitting diode (R/G‐QLED) based on stacked p‐i‐n‐i‐p heterostructures has been invented. It integrates red and green light on one sub‐pixel, reducing the red (R) and green (G) area in traditional RGB three sub‐pixel arrangement techniques. The designed R/G‐QLEDs are achieved by sequentially preparing conventional red and inverted green QLED units on the same substrate by the solution‐processing method, sharing a layer of ZnMgO nanoparticles as the common electron generation layer. Under alternative current (AC) bias, the device enables selective and independent emission of red and green light with high luminance, achieving wide gamut color tuning from red (0.69, 0.30) to green (0.23, 0.73) within a single pixel under controlled electrical modulation. The basic operating mechanism elucidated through transient electroluminescence and direct current (DC) bias analysis reveals efficient, polarity dependent carrier injection, and recombination in different luminescent units. Furthermore, by integrating the R/G‐QLED with a parallel blue QLED unit, we propose a simplified full‐color pixel concept with continuous spectral tunability. The proposed architecture offers significant advantages in structural simplicity, enhanced spatial utilization, and streamlined driving circuitry. This work establishes a promising pathway toward high‐pixel‐density, dynamically color‐tunable displays and intelligent lighting systems.