Our new LEDs are published in Joule! Perovskite materials have the potential to be great LEDs, as very efficient red and green devices have been developed. Yet in order to be used in applications such as TVs and phones, blue LEDs are also required, and these have lagged far behind. We have figured out a surprising way to fix these materials: by adding a dopant, their brightness and efficiency counter-intuitively increase, leading to the highest efficiency blue perovskite LEDs yet demonstrated for lighting applications and showing that these blue materials can be competitive with their red and green cousins. Finally, we also used downconverters at the front of the LED to build an all-perovskite white LED that could someday be used for room lighting.