Energy and Charge Dual Transfer Engineering for High-Performance Green Perovskite Light-Emitting Diodes

Perovskite light-emitting diodes (PeLEDs) have garnered considerable interest in recent years owing to their unique optoelectronic properties. However, the performance of PeLEDs is limited by their low quantum efficiency and unbalanced charge injection. In this study, to address these issues, a novel co-hole transport layer (HTL) of 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) and poly(9-vinylcarbazole) (PVK) is introduced into PeLEDs. By optimizing the composition ratio of CBP and PVK, the performance of CsPbBr₃-based PeLEDs is significantly improved via efficient Förster resonant energy transfer and an enhanced charge transfer owing to the well-aligned energy levels of the HTLs with the emission layers. The PeLED with an optimized composition ratio of the PVK_0.5–CBP_0.5 HTL exhibits the best device performance with a luminance of 31641 cd∙m⁻², current efficiency of 39.2 cd∙A⁻¹, and external quantum efficiency of 15.4%. Thus, the proposed strategy engineering dual transfer of energy and charge is expected to be revolutionary in the field of PeLED research.