Stable Sky‐Blue Perovskite LEDs Achieved by Efficient Sub‐Bandgap Emission With 24.5% PCE
Song Zheng, Zhibin Wang, Guanqin Zheng, Hailiang Huang, Naizhong Jiang, Zhehong Zhou, Ximing Wu, Tao Pang, Lingwei Zeng, Ruidan Zhang, Feng Huang, Daqin Chen
Abstract
Abstract As an emerging light‐source technology, blue perovskite light‐emitting diodes (PeLEDs) have demonstrated remarkable progress in external quantum efficiency. However, their poor operational stability remains a critical bottleneck hindering further commercialization. Simultaneously achieving high power conversion efficiency (PCE) and brightness in the ultralow‐voltage regime represents a promising strategy for realizing long‐lived PeLEDs. Here, efficient defect passivation in perovskite emissive layers is demonstrated through the incorporation of a 0D perovskite phase, while simultaneously modulating the semiconductor characteristics from n‐type to p‐type via strategic bulky cation engineering. The resulting PeLED operates below the bandgap voltage, achieving a high PCE of 24.5%. Notably, the drastically reduced driving voltage suppresses Joule heating and ion migration, extending the operational lifetime to a record T 50 of 318.8 min at 1000 cd m −2 . This work provides a strategic roadmap for developing blue PeLEDs that simultaneously achieve high efficiency, high brightness, and long operational lifetime.