Air-Processed Blue Perovskite Light-Emitting Diodes Enabled by Manipulation of Adsorbed-Moisture-Dominated Crystallization Kinetics

The fabrication of blue perovskite light-emitting diodes (PeLEDs) in air conditions promises to liberate the manipulation procedures from the protection of inert atmosphere in the glovebox, which will remarkably promote the commercialization proceeding of perovskite-based optoelectronic devices in display applications. However, achieving air-processed blue PeLEDs in the interference of moisture meets great challenges in crystallization kinetics control. Herein, it is proposed that substrate-adsorbed moisture dominates the perovskite crystallization kinetics during the fabrication in air, and the limited moisture from nonhygroscopic substrate inhibits the nucleation of the large-n phase and allows the growth of the small-n phase, thus yielding blue quasi-2D perovskite films in a wide moisture range of 10–50% relative humidity. Then, air-processed blue PeLEDs are successfully achieved for the first time, showing a brightness of 968 cd m⁻², external quantum efficiency of 2.54% at stable peak emission of 483 nm, as well as an outstanding operating stability of 546 s at a peak brightness of 45 cd m⁻², which are favorably competitive with PeLEDs fabricated in the glovebox. This work provides a guideline for air-processed blue PeLEDs fabrication, which paves the way for air-processed PeLEDs in further application of commercialization display.