Perovskite Light-Emitting Diodes

Perovskites show exciting potential for photoelectric applications, especially for light-emitting diodes (LEDs), owing to their intrinsically high photoluminescence efficiency and color purity. With efforts made over the last 5 years, the external quantum efficiency (EQE) of lead-halide perovskite-based LEDs has sharply increased beyond 20%, which is comparable to the performance of existing lighting technology. Strategies, including defect passivation, the formation of low-dimensional quantum-well structure perovskites, and a combination of appropriate electron and hole transport materials in electroluminescent devices, not only effectively increases photoluminescence quantum efficiency but also enhances light outcoupling efficiency and carrier transport balance, thus promoting higher efficiency of perovskite LEDs. In this mini review, we will focus on how the EQE can be further increased through diverse perovskite optimization and reasonable device engineering. Furthermore, remaining issues, such as efficiency roll-off at high current density, poor stability, and modest blue perovskite LEDs, are briefly discussed. Perovskite LEDs with high efficiency and long-term stability will accelerate their practical applicability in everyday life.