Dual Optimization of Internal Light Extraction and Hole Injection for High-Efficiency Quantum-Dot Light-Emitting Diodes

Synergistically enhancing internal light outcoupling and hole injection is an ideal strategy for achieving high-performance QLEDs. However, simultaneously optimizing these two parameters remains a significant challenge in the conventional device architecture. Here, we demonstrate conventional red (R-), green (G-), and blue (B-) QLEDs that enable the simultaneous optimization of internal light outcoupling and hole injection. By enhancement of the hole mobility of PEDOT:PSS through Triton X-100 doping, the internal light outcoupling of the device can be optimized without compromising hole injection performance. The hole injection barrier can also be reduced by introducing a 2PACz self-assembled monolayer on the PEDOT:PSS hole injection layer, leading to a marked improvement in hole injection. As a result, the optimized R-, G-, and B-QLEDs achieve excellent external quantum efficiencies (EQEs) of 31.6%, 22.0%, and 9.3%, respectively, significantly outperforming their conventional counterparts. Moreover, the optimized R-QLEDs can also show an exceptional <i>T</i>₉₅ lifetime of 12583 h (at 1000 cd/m²), which is significantly higher than that of the conventional device (5958 h at 1000 cd/m²). We believe that the developed QLEDs, featuring the synergistic enhancement of light outcoupling and hole injection, will further improve the performance of QLEDs and accelerate their commercialization in displays.