One-step formation of core/shell structure based on hydrophobic silane ligands for enhanced luminescent perovskite quantum dots

Abstract

Organometal halide perovskite (MAPbX3; MA = CH3NH3, X = Br, I) quantum dots (QDs) have attracted significant interest as color-adjustable and high-purity light-emitting materials for lighting and display applications. However, the photoluminescence (PL) intensity and lifetime of the organometal halide perovskites are negatively affected by their polarity and poor thermal stability. Here, to improve these issues, the synthesis of hydrophobic MAPbBr3 QDs@SiO2 core/shell structures through a split-ligand mediated re-precipitation (S-LMRP) method is presented. This is done through one-pot process without ligand exchange treatment after QDs synthesis. In this synthesis, 3-aminopropyl(diethoxy)methylsilane (APDEMS) is used as the silica precursor to obtain a hydrophobic surface with –CH3 groups. Therefore, core/shell QDs synthesized using APDEMS are hydrophobic, which induce superior dispersibility. This also have good stability in polar solvents as well as thermal and photo environments, unlike the bare-QDs. This has the advantage of not only protecting the perovskite core due to the shell, but also suppressing the release of heavy metals. Moreover, it has a relatively narrow full width at half-maximum and a PL quantum yield of 96.5%. Turbiscan measurements demonstrated better dispersibility in the newly designed core/shell QD compared to the conventional QD (agglomerated in suspension). Finally, this proposed method enable is applicable to the preparation of not only green but also red and blue light-emitting core/shell QDs, which is expected to have an attractive impact for display applications. © 2021 Elsevier B.V.