Highly efficient pixelated quantum-dot light-emitting diodes enabled by bi-color-converting cavities

Abstract

Fabricating quantum-dot (QD) light-emitting diode (LED) arrays typically relies on direct QD patterning or costly color filters (CFs), highlighting the need for cost-effective patterning techniques to achieve high-efficiency pixelated QLEDs. This study presents a bi-color-converting cavity that transforms yellow emissions from non-patterned mixed red and green QDs into saturated red and green emissions by adjusting the thickness of the indium-zinc-oxide phase tuning layer. Excluding blue QDs with low quantum yields and high injection barriers, this approach is expected to achieve excellent device performance tailored for specific outdoor display applications. The cavity yellow QLEDs exhibit maximum current efficiencies of 28.20 and 36.32 cd/A for red and green emissions, representing enhancements of 144% and 148% over CF yellow QLEDs, respectively. These improvements stem from the bi-color-converting cavity, which enhances the forward emissions in the cavity yellow QLED and redistributes exciton energy in mixed QDs by modulating the energy transfer. Furthermore, bi-color pixelated QLEDs with a resolution of 423 pixels per inch have been demonstrated. This bi-color-converting cavity technique relies on established photolithography techniques and holds great potential in high-performance and high-resolution display applications.