The paper presents a significant advancement in the performance of perovskite light-emitting diodes (pLEDs) by achieving an external quantum efficiency (EQE) exceeding 20%. The researchers developed a new compositional distribution management strategy that combines high luminescence with balanced charge injection. By mixing CsPbBr3 perovskite with MABr (CH3NH3Br) in the precursor, they created a quasi-core-shell structure that passivates non-radiative defects and enables balanced charge injection. This approach resulted in pLEDs with an EQE of 20.3%, surpassing the performance of both organic LEDs (OLEDs) and inorganic quantum dot LEDs (QLEDs). The study also highlights the importance of device stability, which remains a critical challenge for pLEDs, and suggests potential solutions such as suppressing ion migration and optimizing the perovskite/ETL and perovskite/HTL interfaces. The findings pave the way for practical commercialization of pLEDs in lighting and display applications.The paper presents a significant advancement in the performance of perovskite light-emitting diodes (pLEDs) by achieving an external quantum efficiency (EQE) exceeding 20%. The researchers developed a new compositional distribution management strategy that combines high luminescence with balanced charge injection. By mixing CsPbBr3 perovskite with MABr (CH3NH3Br) in the precursor, they created a quasi-core-shell structure that passivates non-radiative defects and enables balanced charge injection. This approach resulted in pLEDs with an EQE of 20.3%, surpassing the performance of both organic LEDs (OLEDs) and inorganic quantum dot LEDs (QLEDs). The study also highlights the importance of device stability, which remains a critical challenge for pLEDs, and suggests potential solutions such as suppressing ion migration and optimizing the perovskite/ETL and perovskite/HTL interfaces. The findings pave the way for practical commercialization of pLEDs in lighting and display applications.