Perovskite Nanocatalsts Protected by Hermetically Sealing for Highly Bright and Stable Deep-Blue Light-Emitting Diodes

Metal–halide perovskite nanocrystals (NCs) have emerged as suitablelight-emitting materials for light-emitting diodes (LEDs) and other practicalapplications. However, LEDs with perovskite NCs undergoenvironment-induced and ion-migration-induced structural degradationduring operation; therefore, novel NC design concepts, such as hermeticsealing of the perovskite NCs, are required. Thus far, viable syntheticconditions to form a robust and hermetic semiconducting shell on perovskiteNCs have been rarely reported for LED applications because of the difficultiesin the delicate engineering of encapsulation techniques. Herein, a highlybright and durable deep-blue perovskite LED (PeLED) formed by hermeticallysealing perovskite NCs with epitaxial ZnS shells is reported. This shellprotects the perovskite NCs from the environment, facilitates chargeinjection/transport, and effectively suppresses interparticle ion migrationduring the LED operation, resulting in exceptional brightness (2916 cd m−2)at 451 nm and a high external quantum efficiency of 1.32%. Furthermore,even in the unencapsulated state, the LED shows a long operational lifetime(T50) of 1192 s (≈20 min) in the air. These results demonstrate that theepitaxial and hermetic encapsulation of perovskite NCs is a powerful strategyfor fabricating high-performance deep-blue-emitting PeLEDs.