Polycrystalline 3D CsPbBr 3 Green Perovskite Light‑Emitting Diodes: From Fundamentals to Device Engineering

ABSTRACT Inorganic cesium lead bromide (CsPbBr 3 ) has become a leading candidate for emissive layers in light‐emitting diodes (LEDs) because it offers better thermal and chemical stability than its organic counterparts. After years of intensive research, 3D CsPbBr 3 perovskite LEDs (PeLEDs) incorporating polycrystalline green‐emitting layers now achieve a peak external quantum efficiency of 32.1% and an operational lifetime of 185 600 h at an initial luminance of 100 cd m −2 . These remarkable results highlight the need for a comprehensive review that not only summarizes the progress made to date but also critically assesses the current state of 3D CsPbBr 3 polycrystalline green‐emitting PeLEDs. This review first covers the fundamental aspects of CsPbBr 3 PeLEDs (device architecture, working principle, charge carrier dynamics, and performance metrics), then examines the various fabrication methods, identifies the persistent challenges, and evaluates the device engineering strategies devised to improve both the efficiency and operational longevity of the devices. Finally, it offers insights into cutting‑edge approaches to further enhance device performance and accelerate the practical deployment of 3D CsPbBr 3 polycrystalline green‐emitting PeLED technology.