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In this paper, a 0.47 inch active‐matrix microdisplay with top‐emitting monochromatic quantum dot light‐emitting diode (QLED) array on silicon is demonstrated. A titanium nitride (TiN) is employed as the anode and the devices are fabricated by all‐solution process. The driver chip is designed especially for QLED microdisplay. The demonstrated microdisplay exhibits a maximum brightness of 267 cd/m2 and a gray level of 256. [ABSTRACT FROM AUTHOR]

Abstract: The performance of the blue quantum dot light‐emitting diodes (QLEDs) is largely affected by the hole transport layers (HTLs). As a consequence of the deep valance band level of blue quantum dots (QDs), hole injection is relatively difficult in blue QLEDs. To favor the hole injection, HTLs with high hole mobility and deep‐lying highest occupied molecular orbital level are desired. In this work, various HTLs and their influence on the performance of blue QLEDs are demonstrated. Devices with poly(N‐vinylcarbazole) (PVK) HTL exhibit the highest external quantum efficiency while devices with poly[9,9‐dioctylfluorene‐co‐N‐(4‐(3‐methylpropyl))‐diphenylamine] (TFB) exhibit the lowest driving voltage. By combining the advantages of PVK and TFB, the blue QLEDs with TFB/PVK bilayered HTL simultaneously exhibit a low driving voltage of 2.6 V and a high external quantum efficiency of 5.9%. Moreover, the exciplex emission at the interface of HTL/QDs is also observed, and the emission intensity can be tuned by modulating the hole injection. By utilizing PVK doped with 25% poly(3‐hexylthiophene) (P3HT) as HTL, exciplex emission is significantly enhanced at low driving voltage while QD emission is dominant at high driving voltage. By combining the exciplex emission and the QD emission, the emission color can be effectively tuned from red to blue as the driving voltage changing from 2 to 10 V. [ABSTRACT FROM AUTHOR]

Flexible quantum dotlight‐emitting diodes (QLEDs) are demonstrated by using hot‐pressing AgNWs as the transparent conductive electrode and EGaIn as the back electrode. Both AgNWs and EGaIn are printable, and thus the whole device can be fabricated via vacuum‐free processes. The hot‐pressing AgNWs electrode exhibits excellent physical characteristics such as high transparency of 96.7% in the visible spectral region, and low sheet resistance of 28 Ω/sq. With the AgNWs and EGaIn, vacuum‐free‐fabricated QLEDs are successfully achieved with efficiency 13.2cd/A. Because of the elimination of the costly vacuum processes, the proposed fabrication processes are low cost and allow rapid fabrication of flexible QLEDs with high performance. [ABSTRACT FROM AUTHOR]