Achieving high efficiency and stable pure blue colloidal perovskite quantum dot (QD) light-emitting diodes (LEDs) is still an enormous challenge. This paper presents a room-temperature synthesis method using organic cation composition modification to create high-performance pure blue perovskite quantum dots. FA-CsPb(Cl₀.₅Br₀.₅)₃ QDs exhibit a high PLQY (65%), resulting in pure blue LEDs with a maximum luminance of 1452 cd m⁻² and an external quantum efficiency of 5.01% at 474 nm. The improved performance is attributed to enhanced blue QD emitters and effective charge injection and exciton radiation.
