Self-Generated Buried Submicrocavities for High-Performance Near-Infrared Perovskite Light-Emitting Diode

Embedding submicrocavities is an effective approach to improve the light out-coupling efficiency (LOCE) for planar perovskite light-emitting diodes (PeLEDs). In this work, we employ phenethylammonium iodide (PEAI) to trigger the Ostwald ripening for the downward recrystallization of perovskite, resulting in spontaneous formation of buried submicrocavities as light output coupler. The simulation suggests the buried submicrocavities can improve the LOCE from 26.8 to 36.2% for near-infrared light. Therefore, PeLED yields peak external quantum efficiency (EQE) increasing from 17.3% at current density of 114 mA cm^-2 to 25.5% at current density of 109 mA cm^-2 and a radiance increasing from 109 to 487 W sr^-1 m^-2 with low rolling-off. The turn-on voltage decreased from 1.25 to 1.15 V at 0.1 W sr^-1 m^-2. Besides, downward recrystallization process slightly reduces the trap density from 8.90 × 10¹⁵ to 7.27 × 10¹⁵ cm^-3. This work provides a self-assembly method to integrate buried output coupler for boosting the performance of PeLEDs.