Boosting Efficiency and Longevity of Quantum Dot Light-Emitting Diodes with Dibenzofuran-Incorporated Hole Transport Materials Featuring High Bond Dissociation Energy

The intrinsic degradation of quantum dot light-emitting diodes (QLEDs) is often attributed to the insufficient stability of hole transport materials (HTMs), which adversely affects both efficiency and operational lifetime. Despite efforts to address this issue, HTMs with high bond dissociation energy (BDE) for enhanced QLED performance remain underdeveloped. Here, a series of dibenzofuran (DBF)-incorporated HTMs with high BDE is synthesized to improve QLED efficiency and longevity. Among them, poly(9,9-dioctylfluorene-co-N,N-diphenyldibenzo[b,d]furan-1-amine) (1-PFDBF) exhibits superior hole mobility, high BDE, extended exciton lifetime, and reduced trap density. Green QLEDs employing 1-PFDBF achieve a maximum external quantum efficiency (EQE_max) of 25.71%, a maximum current efficiency of 102.98 cd A⁻¹, and a maximum power efficiency of 75.69 lmW⁻¹, significantly outperforming poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)diphenylamine) (TFB)-based QLEDs. Notably, the EQE_max of 1-PFDBF-based green QLEDs ranks among the highest for devices utilizing triarylamine-based HTMs. Furthermore, the operational half-lifetime of the 1-PFDBF-based QLEDs is ≈15 900 h at 1 000 cd m⁻² and ≈1 460 000 h at 100 cd m⁻², making a significant increase of 3 600% and 6 600%, respectively, compared to TFB-based QLEDs. These findings establish DBF incorporation as an effective strategy for enhancing HTM BDE and hole mobility, optimizing charge balance within QLEDs, and ultimately enabling high-efficiency and long-lasting QLEDs.