FAPbBr3@GA2PbBr4 quantum dots: one step fabrication with improved stability for light-emitting applications†

Perovskite quantum dots (QDs), with outstanding properties, including tunable emissions, high color purity, and low cost solution processability, have become promising candidates in light-emitting applications. However, the inherent instability issue strongly restricts further development and commercialization of light-emitting devices based on perovskite QDs. As well investigated in conventional QDs, the construction of QDs with core–shell structure is recognized as an effective way to improve the stability and optimize luminescent properties at the same time. Inspired by the unique structure diversity of perovskite materials, 2D/3D FAPbBr₃@GA₂PbBr₄ QDs are proposed and fabricated through a one-step phase transfer enhanced emulsion synthesis. By systematically tuning the ratio between GABr and FABr as well as a combined analysis with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, absorption and photoluminescence spectrum characterizations, a well-defined core–shell structure is demonstrated for FAPbBr₃@GA₂PbBr₄ QDs under an appropriate ratio of GABr/FABr. Compared to the original QDs, the as fabricated core–shell QDs exhibit an enhanced exciton binding energy and improved stability under heat, light, and moisture exposure. Moreover, phosphor converted light-emitting diodes based on the core–shell QDs are also fabricated with a much improved device performance than that of QDs without a core–shell structure, proving the superiority of FAPbBr₃@GA₂PbBr₄ QDs in light-emitting applications.