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Simultaneous Improvement in Blue-Light Emission and Operational Stability of Nanometer-Thick Perovskite Light-Emitting Diodes by Incorporating Multiple Organic/Inorganic Chloride Salts

2024; American Chemical Society; Volume: 7; Issue: 22 Linguagem: Inglês

10.1021/acsanm.4c04882

2574-0970

Jung Jae, Donghan Kim, Jae Woong Jung,

Conducting polymers and applications

Although recent advancements in organic–inorganic hybrid perovskites have captivated not only the community of photovoltaics but also the field of display technologies, the development of perovskite-based light-emitting diodes (PeLEDs) with pure-blue emission has lagged behind that of their green- or red-emitting counterparts in terms of optoelectronic properties and operational stability. In this study, we report a comprehensive strategy to enforce pure-blue emission of PeLEDs with high quantum efficiency and operational stability by introducing multiple cationic chlorides in perovskite layers. First we demonstrate the gradual induction of a distinct hypsochromic shift to the blue region in green-emissive CsFAPbBr3 perovskite films by incorporating bulky ammonium bromide and chloride. This shift is accomplished through dimensional and lattice structure engineering. Second, small A-site cationic chlorides are introduced to further tune the band gap and optoelectronic properties of the pure-blue PeLEDs. Finally, yttrium(III) chloride is introduced as an additive to hamper severe phase segregation and ion migration in the perovskite emitting layers. As a result of these deliberate modifications, the proper inclusion of multiple inorganic chloride salts enforced the hypsochromic shift of the perovskite layer with a minimized defect density, leading to pure-blue electroluminescence at 472 nm with an exceptionally narrow bandwidth of 17.91 nm and an external quantum efficiency of 4.22%. The optimized chlorides also achieve superior operational stability with an electroluminescence half-life of 23 min at an initial luminance of 350 cd/m2 in an ambient atmosphere. This suggests a straightforward way to prepare practical pure-blue PeLEDs for achieving full-color perovskite display technologies.