Stabilizing Perovskite Light‐Emitting Diodes by Alternating Current

Abstract Ion migration is inevitable for perovskite light‐emitting diodes (PeLEDs) operating under a constant direct current (DC) electric field, significantly undermining device stability. Herein, a straightforward and effective strategy is presented for boosting the lifetime of PeLEDs by employing an alternating current (AC)‐driving mode. The impact of driving mode on device performance is investigated, achieving a record external quantum efficiency (EQE) of 14.9% under AC‐driving mode with negligible efficiency roll‐off (EQE >13.5%) across a wide range of current densities (1 to 400 mA cm −2 ). Notably, the effectively suppressed ion migration is demonstrated in AC‐driving mode, resulting in a remarkable 40‐fold increase in operational lifetime ( T 50 ) compared to the DC‐driving mode. This enhancement is particularly pronounced in mixed‐halide PeLEDs (e.g., FAPbI 2 Br), where the challenging issue of spectral drift due to ion migration has been effectively resolved.