摘要： Perovskite nanocrystals exhibit high photoluminescence quantum yields (PLQYs) and tunable bandgaps from ultraviolet to infrared. However, blue perovskite light-emitting diodes (LEDs) suffer from color instability under applied bias. Developing narrow-bandwidth deep-blue emitters will maximize the color gamut of display technologies. Mixed anion approaches suffer from halide segregation that leads to their spectral instability. Here instead, a mixed cation strategy is employed whereby Rb+ is directly incorporated during synthesis into CsPbBr3 nanocrystals. Blue-emitting perovskite quantum dots (QDs) with stable photoluminescence, PLQYs greater than 60%, tunable emission from 460 to 500 nm, and narrow emission linewidths (<25 nm) are reported. The strategy retains a pure bromine crystal structure resulting in color-pure stable electroluminescence at operating voltages of up to 10 V, peak external quantum efficiencies (EQEs) of 0.87% and 0.11% for sky-blue (490 nm), and deep-blue (464 nm) devices. The sky-blue devices exhibit the highest combined luminance of 93 cd m?2 at an EQE of 0.75%, the best reported to date of perovskite QD LEDs.