Minimizing Interfacial Energy Losses with Carbon Dot Bifacial Modification Layers for High‐Efficiency and Stable Perovskite LEDs

Abstract Perovskite light‐emitting diodes (PeLEDs) have reached near‐unity photoluminescent quantum yields (PLQYs), but further improvements in electroluminescent efficiency are constrained by interfacial energy losses between the emissive layer and charge transport layers. In this study, multifunctional carbon dot organic frameworks (CDOFs) are introduced as a dual‐interface modification material for perovskite layer. This approach effectively passivates both the upper and buried interfaces, boosting the PLQY to nearly 100% and enabling an external quantum efficiency of 28.0%. The CDOFs also facilitate balanced charge injection, achieving a low turn‐on voltage of only 1.9 V, significantly below the bandgap voltage. Additionally, the exceptional defect passivation imparted by CDOFs significantly bolsters structural stability, achieving a T 50 operational lifetime of 81.7 min at an initial ultrahigh luminance of 10 000 cd m −2 , with no detectable Joule heating. This study underscores the potential of CDOFs in significantly advancing PeLED performance.