Ultrabright and stable top-emitting quantum-dot light-emitting diodes with negligible angular color shift

Abstract

Top emission can enhance luminance, color purity, and panel-manufacturing compatibility for emissive displays. Still, top-emitting quantum-dot light-emitting diodes (QLEDs) suffer from poor stability, low light outcoupling, and non-negligible viewing-angle dependence because, for QLEDs with non-red emission, the electrically optimum device structure is incompatible with single-mode optical microcavity. Here, we demonstrate that by improving the way of determining reflection penetration depths and creating refractive-index-lowering processes, the issues faced by green QLEDs can be overcome. This leads to advanced device performance, including a luminance exceeding 1.6 million nits, a current efficiency of 204.2 cd A−1, and a T95 operational lifetime of 15,600 hours at 1000 nits. Meanwhile, our design does not compromise light outcoupling as it offers an external quantum efficiency of 29.2% without implementing light extraction methods. Lastly, an angular color shift of Δu’v’ = 0.0052 from 0° to 60° is achieved by narrowing the emission linewidth of quantum dots.

Improved Charge Injection Balance in Quantum Dot Light-Emitting Diodes through Interface Texture

“…These LEDs offer high color saturation, near Rec. 2020 color gamut, brightness of over 1 million cd m –2 , quantum efficiency of over 30%, and sustainably progressing operational lifetime. − They are also compatible with cost-effective panel manufacturing processes and multiple patterning techniques. , These exciting developments indicate that the goal of commercializing QLED displays, one of CQD research’s major objectives, is probably within close reach.…”