Edge stabilization in reduced-dimensional perovskites.

ABSTRACT: Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97?±?3% photoluminescence quantum yields and stabilities that exceed 300?h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000?cd?m-2; their maximum luminance is 4.5?×?104?cd?m-2 (corresponding to an EQE of 5%); and, at 4000?cd?m-2, they achieve an operational half-lifetime of 3.5?h.

SUBMITTER: Na Quan L 

PROVIDER: S-EPMC6954198 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature