image: Color-tunable single-layer arrayed QLEDs demonstrating the ability to display different colors and patterns through voltage control.
Credit: ©Science China Press
In the pursuit of advanced display technologies, a persistent challenge lies in developing individual pixels capable of color-tunable emission without complex fabrication processes. Conventional approaches often rely on stacked multi-layer architectures, which introduce manufacturing defects and escalate production costs. Addressing this, a research team from Nanjing University of Science and Technology has engineered a single-layer color-tunable QLEDs technology where color emission is dynamically tunable through voltage modulation.
The innovation stems from the synergistic integration of two materials: AgInZnS (AIZS) quantum dots (QDs) and organic interface exciplexes. Under applied voltage, exciplexes act as energy donors, transferring energy to adjacent QDs via Förster resonance energy transfer (FRET). At low voltages, efficient FRET induces QDs luminescence, while higher voltages suppress energy transfer, enabling exciplex emission. This voltage-dependent interplay allows single pixels to precisely control color transitions, such as green to blue or red to yellow.
"The elegance of this design lies in its simplicity and efficacy," the authors emphasize. "By leveraging intrinsic energy transfer within a monolayer structure, we circumvent the need for intricate tandem configurations. This not only streamlines fabrication but also enhances device performance."
The single-layer color-tunable QLEDs achieved a record-breaking 5% external quantum efficiency (EQE) for quaternary alloy AIZS QDs-based devices, validated by uniform light emission in patterned and large-area formats. Demonstrations include arrayed QLEDs exhibiting distinct colors and patterns, such as “NJUST” letter patterns, by independently controlling the voltage applied to each pixel.
This research, published in Science Bulletin, establishes a scalable strategy for next-generation displays. The single-pixel, voltage-tunable architecture delivers three pivotal advantages—enhanced color gamut, simplified manufacturing, and improved device performance—all of which are key attributes for high-resolution full-color display and lighting technologies. The work was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, International Cooperation Program of Jiangsu Province of China, and the Fundamental Research Funds for the Central Universities.