Metal halide perovskites (MHPs) have emerged as promising candidates for next-generation display because of their advantages on luminescent properties and external quantum efficiency exceeding 20 % in less than 5 years since the first efficient EL operation. However, the short operational lifetime of PeLEDs is limiting their practical application. Especially, the ion migration in perovskite under intense electric field is known to destroy the crystal structure and cause device failure.
Here, we suggest new strategies to overcome the lifetime limitation of PeLEDs. First, we introduced the proton-transfer-induced 3D/2D hybrid structure with extremely suppressed ion migration and low defect density, showing extremely suppressed luminance overshoot and >20 times longer operational lifetime. Also, we could further prolong the lifetime of PeLEDs by using ideal mixed-cation system and suppressing the electric-field-induced catastrophic failure by inducing self-assembled core/shell structure.