Bottom up Stabilization of CsPbBr3 Quantum Dots-Silica Sphere with Selective Surface Passivation via Atomic Layer Deposition

All-inorganic perovskite quantum dots suffer from poor stability in a humid and heat environment. In this article, CsPbBr3 quantum dots (CsPbBr3 QDs) are stabilized by coating nanoscale alumina on a CsPbBr3 QDs-silica luminescent sphere (CsPbBr3 QDs-SLS) via atomic layer deposition (ALD). Utilizing the intrinsic reactivity differences toward precursors, the surface defect sites of CsPbBr3 QDs are selectively passivated. The inorganic alumina coating layers can effectively reduce the ion migration and crystal deformation of CsPbBr3 QDs. In situ quartz crystal microbalance measurements show that organic ligands remain attached to the CsPbBr3 QDs surface during the ALD coating process. NMR, XPS, and first-principles calculations are performed to reveal the interaction strength between CsPbBr3 QDs-SLS and precursors. The surface passivation of alumina on CsPbBr3 QDs-SLS effectively stabilizes the QDs without reducing the photoluminescent quantum yield.