50‐Fold EQE Improvement up to 6.27% of Solution‐Processed All‐Inorganic Perovskite CsPbBr3 QLEDs via Surface Ligand Density Control

Solution-processed CsPbBr3 quantum-dot light-emitting diodes with a 50-fold external quantum efficiency improvement (up to 6.27%) are achieved through balancing surface passivation and carrier injection via ligand density control (treating with hexane/ethyl acetate mixed solvent), which induces the coexistence of high levels of ink stability, photoluminescence quantum yields, thin-film uniformity, and carrier-injection efficiency.