Highly Bright and Stable Lead-Free Double Perovskite White Light-Emitting Diodes.

Lead-free double perovskites (DPs) are emerging highly stable emitters with efficient broadband self-trapped exciton (STE) photoluminescence (PL), but their low electroluminescent (EL) efficiency is a critical shortcoming. We promoted the external quantum efficiency (EQE) and luminance of DP-based white light-emitting diode (wLED) with a normal device structure to 0.76% and 2793 cd m -2 via two modifications: We prevented the formation of adverse metallic silver, spatially confined STE, and lowered local site symmetry in Cs 2 Na 0.4 Ag 0.6 In 0.97 Bi 0.03 Cl 6 DP by terbium doping; and we developed a guest-host strategy to improve film morphology, reduce defect density and increase carrier mobility. These alterations caused substantial increases in STE radiative recombination and charge injection efficiency of perovskite layer. Finally, pure white EL with ideal color coordinates of (0.328, 0.329) and a record-breaking optoelectronic performance was achieved by introducing additional green carbon dots in LED to fill the deficient green component. This article is protected by copyright. All rights reserved.