Synergistic Dual-Passivation via Indium Doping and Zwitterionic Ligands for Efficient Pure-Blue Perovskite Light-Emitting Diodes

The development of pure blue perovskite light-emitting diodes (PeLEDs) for displays has lagged significantly behind that of green- and red-emitting PeLEDs. Mixed halide perovskite (Br/Cl) perovskite nanocrystals (NCs) are typically employed for blue emission but suffer from halide vacancies and ion migration. Here, we report a dual-passivation strategy using In³⁺ ion doping and zwitterionic ligand 3-(decyldimethylazaniumyl)propane-1-sulfonate (SB3-10) to enhance the stability and optical performance of CsPb(Br/Cl)₃ NCs. In³⁺ doping stabilizes the crystal structure and reduces halide vacancy defects, while SB3-10 ligands coordinate with surface Pb²⁺ ions to passivate defects, suppress ion migration, and prevent halide vacancy formation. This approach results in significantly enhanced stability and photoluminescence quantum yield. Using these dual-passivated InSB/NCs as the emitting layer, we fabricated spectrally stable pure-blue LEDs with an emission peak at 468 nm, achieving a significantly improved external quantum efficiency (12.2%, 7-fold higher), maximum luminance (364.7 cd m^–2, 5-fold higher), and half-life (159.2 s, 9.4-fold higher) compared to the device fabricated with unmodified CsPb(Br/Cl)₃ NCs. This approach has important implications for the development of efficient, stable, and pure blue perovskite LEDs.