Neutral inorganic salt additives universally regulate multicolor perovskites for efficient electroluminescence

(X = Br and Cl) component can be increased from 5.6% to 9.6%. The maximum EQE of pure blue PeLEDs (474 nm) can be increased from 3% to 4%. This class of neutral additives provides a solution for high-performance quasi-2D perovskite electroluminescence.