Nanostructured ZnMgO Charge Generation Layers for Enhanced Tandem Quantum-Dot Light-Emitting Diodes

초록

Tandem quantum-dot light-emitting diodes (QLEDs) offer a promising route to high-brightness displays, but their performance critically depends on efficient and optically transparent charge generation layers (CGLs). Here, we introduce a nanostructured ZnMgO/poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4 '-(N-(p-butylphenyl))diphenylamine)] (TFB) bilayer CGL for solution-processed tandem QLEDs. Slowly synthesized ZnMgO nanoparticles formed a highly textured surface that was conformally covered by TFB, enlarging the effective interfacial area while providing favorable wettability and energy-level alignment. The resulting ZnMgO/TFB CGL-only device exhibited a charge-generation current density approximately 160% of that obtained with a conventional ZnMgO/PEDOT:PSS CGL. Moreover, the bilayer maintained over 95% transmittance across the visible region, thereby minimizing optical losses. Green tandem QLEDs incorporating the nanostructured CGL achieved a maximum luminance of 100,289 cd/m, a maximum current efficiency of 28.2 cd/A, and a low turn-on voltage of 4.5 V. These results establish nanostructured ZnMgO/TFB bilayers as a simple and effective CGL architecture for high-performance tandem QLEDs.

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