Buried interface anchored octahedra for efficient sky-blue perovskite light-emitting diodes

Challenges such as interfacial nonradiative recombination and halogen phase separation have impeded the progress of blue PeLEDs. Here, a triammonium citrate layer is buried beneath perovskite films, which reorganizes the phase distribution and inhibits interfacial nonradiative recombination by anchoring PbX₆^4- octahedra. By settling these key issues, efficient stable sky-blue PeLEDs have been successfully developed. The devices have achieved an impressive efficiency of 7.07% at 478 nm, evidencing efficient and stable sky-blue PeLEDs.