SiOx-Encapsulated MAyCs1-yPbX3 Perovskites via One-Pot and Post-Synthetic Routes for Tunable Bandgap for White Emission and Photocatalysis

Halide perovskites (HPs) with various dimensional variations have been established as potential materials to fabricate efficient solar light conversion systems, display devices, thin-film transistors, as well as prominent photocatalysts to trigger solar-driven applications. However, to practically use HPs and focus efforts on their prominent commercialization, degradation mechanisms, strategies for enhancing material stability, and device operating durability are being widely studied. One of them, in this contribution, amorphous silica covered perovskite quantum dot (PQD) structure was studied for understanding i) formation mechanism of MAyCs1-yPbX3@SiOx, and their halide exchange processes during synthetic stage or post-synthetic stage, and ii) the effect of non-stoichiometric A-site/X-site ion composition to photoexcited electron recombination dynamics in the MAyCs1-yPbX3@SiOx PQDs. Through the modification of the ligand-assisted reprecipitation synthetic methods about the conventional CsPbBr3@SiOx to obtain multi-colored MAyCs1-yPbX3@SiOx, the color gamut is comparable to the Rec. 2020 standard up to 93.55% with more pristine blue/red emissions. In addition, these PQDs@SiOx can facilitate the photocatalytic oxidation of benzyl alcohol in ethanol via chemisorption through Si-OH silanol groups, reaching a photodegradation efficiency of ~35%. This work demonstrates the versatile potential of PQDs to be used in display technologies and perform photocatalytic reactions in polar solvents.