Regulating Crystallization and Carrier Recombination of Quasi-2D Perovskite for Efficient Air-Processed Light-Emitting Diodes

Fabricating perovskite light-emitting diodes (PeLEDs) in ambient air is beneficial for reducing the production costs and promoting their further applications. However, the device performance is significantly restricted by the uncontrolled crystallization and unfavorable carrier recombination of the perovskite films when processing under an ambient environment. In this work, we report an effective strategy to tackle these issues by introducing a bifunctional molecule, formamidinium trifluoroacetate (FATFA). It is found that FATFA can accelerate the crystallization and reduce the defects in perovskites to improve carrier recombination. Accordingly, the air-processed green PeLEDs based on FATFA optimization exhibit a high external quantum efficiency exceeding 16%, with a maximum luminance approaching 33,000 cd m-2 and an operational half-lifetime of nearly 25 min at an initial brightness of ∼900 cd m-2, which represent the best-performed air-processed PeLEDs. This work provides a feasible way to realize cost-efficient PeLEDs and boost their practical applications in the future.