Toward Stable and Efficient Perovskite Light‐Emitting Diodes

Abstract Metal halide perovskites (MHPs) are a promising class of materials for next‐generation display and lighting applications. Since the first demonstration of bright electroluminescence (EL) from perovskite light‐emitting diodes (PeLEDs) in 2014, the EQEs of these devices increased from below 1% to more than 20% in merely four years. Despite the meteoritic rise of device efficiencies that placed the new LED technology in the spotlight, many scientific and technical challenges remain, preventing PeLEDs from advancing further into practical applications. The success of inorganic III‐V LEDs, or commercial LED technologies in general, lies in the ability to demonstrate the reliable generation of blue EL. For PeLEDs, high operational stability and efficient blue EL remain to be some of the most pressing goals. To accelerate further developments in these areas, the recent progress in the research of PeLEDs is reviewed. The authors attempt to establish preliminary connections between the degradation mechanisms and the strategies for improvements, exemplified by a selection of recent representative works in the field. Lessons learned from organic LEDs and perovskite solar cells point toward some of the most important directions. This progress report serves as a catalyst for further interdisciplinary research involving materials scientists, chemists, and physicists working together to realize operationally stable PeLEDs.