Charge Carrier Regulation for Efficient Blue Quantum-Dot Light-Emitting Diodes Via a High-Mobility Coplanar Cyclopentane[ b ]thiopyran Derivative.

The performance of blue quantum dot light-emitting diodes (QLEDs) is limited by unbalanced charge injection, resulting from insufficient holes caused by low mobility or significant energy barriers. Here, we introduce an angular-shaped heteroarene based on cyclopentane[ b ]thiopyran (C 8 -SS) to modify the hole transport layer poly- N -vinylcarbazole (PVK), in blue QLEDs. C 8 -SS exhibits high hole mobility and conductivity due to the π···π and S···π interactions. Introducing C 8 -SS to PVK significantly enhanced hole mobility, increasing it by 2 orders of magnitude from 2.44 × 10 -6 to 1.73 × 10 -4 cm 2 V -1 s -1 . Benefiting from high mobility and conductivity, PVK:C 8 -SS-based QLEDs exhibit a low turn-on voltage ( V on ) of 3.2 V. More importantly, the optimized QLEDs achieve a high peak power efficiency (PE) of 7.13 lm/W, which is 2.65 times that of the control QLEDs. The as-proposed interface engineering provides a novel and effective strategy for achieving high-performance blue QLEDs in low-energy consumption lighting applications.