Bright and efficient quantum dot light-emitting diodes with double light-emitting layers

We demonstrate high brightness and efficient light-emitting diodes (QLEDs) with 60-nm-thick double quantum dot light-emitting layers (D-EMLs) based on poly(p-phenylene benzobisoxazole) precursors. This structure distributes the charge balance by blocking electrons. The D-EML QLEDs exhibit significant improvement in brightness, efficiency, and stability. The external quantum efficiency and luminance of D-EML QLEDs show 170% and 48% enhancement compared with a single light-emitting layer, respectively. The efficiency roll-off of D-EML QLEDs is only 16% of that of the S-EML up to 10 V.