Phase stabilization for high-performance perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) have shown great potential for next-generation display and solid-state lighting applications. In the related field of perovskite solar cells, preventing the conversion of the photovoltaically active black phase (α-phase) into the less desirable yellow phase (δ-phase) is of critical importance for achieving efficient and stable solar cells based on formamidinium lead iodide (FAPbI3) perovskite. Similar issues related to phase stability are expected to occur in PeLEDs, leading to reduced operational stability and the formation of additional electronic traps. In this work, we introduce an additive, sulfobetaine 10 (SFB-10), into the FAPbI3 perovskite for α-phase stabilization. The SFB-10 incorporated perovskite films show enhanced crystallinity, reduced defect density and improved α-phase stability, leading to high-performance PeLEDs with external quantum efficiencies exceeding 16%, and T90 (the time for radiance to decrease to 90% of its initial value) of over 1000 s at 200 mA cm-2 in air, offering a comparable performance to some of the most stable PeLEDs reported to date. This work may contribute to the development of stable perovskite light-emitting diodes.