Synergistical Electroluminescent Manipulation for Efficient Blue Perovskite Light-Emitting Diodes Through Interfacial Nucleation Seeding

Abstract: The low efficiency of metal halide perovskite light-emitting diodes (PeLEDs) with blue emission block their potential applications in large-area full-color displays and solid-state lighting. A delicate control over the entire electroluminescence process is indispensable to overcome the efficiency limitations of blue PeLEDs. Here, we demonstrate an efficient device architecture to synergistically reduce the energetic losses during electron-photon conversion and boost the extraction of trapped light in the device. An interfacial nucleation seeding scheme is proposed to control the crystallization process of highly emissive perovskite nanocrystals and suppress the trap-mediated non-radiative recombination losses due to interfacial hydrogen bonding interactions. This manipulation results in a record external quantum efficiency (EQE) of 12.8% for blue PeLEDs emitting at 486 nm, along with the improved spectral stability and operation lifetime. Additionally, the maximum EQE reaches 16.8% after combining an internal outcoupling structure without spectral distortion, which can be further raised to 27.5% when using a lens-based structure on top of the device. We anticipate that our work provides an effective method for its application in high-performance PeLEDs.