In‐Situ Anchoring Pb‐Free Cs₃Bi₂Br₉@BiOBr Quantum Dots on NH_x‐Rich Silica with Enhanced Blue Emission and Satisfactory Stability for Photocatalytic Toluene Oxidation

Abstract

All‐inorganic metal halide perovskite quantum dots (QDs) have attracted attention from researchers with their fascinating optoelectronic properties. However, blue‐emitting perovskite QDs typically have low photoluminescence quantum yield (PLQY). For potential commercial applications, it is preferable to replace Pb with an element having low toxicity. Here, Pb‐free Cs3Bi2Br9@BiOBr perovskite QDs were anchored on the surface of NHx‐rich monodisperse silica (A−SiO2) via N−Bi chemical bonding to isolate QDs from each other, thus enhancing efficient surface passivation and suppressing optical decay. Compared to unanchored QDs, Cs3Bi2Br9@BiOBr QDs/A−SiO2 composites exhibited significantly enhanced blue emission performance, the PLQY of which increased from 16.62 % to 77.26 %, in addition to good water and environmental stability. Finally, the novel composites as photocatalysts were used to drive the oxidation of toluene, a template reaction of C(sp3)−H bond activation and demonstrated astonishing conversion rates (4317 μmol g−1 h−1) with high selectivity (around 87 %).

Improving the stability of perovskite nanocrystals via SiO2 coating and their applications

“…Therefore, amino and carboxyl-modified SiO 2 can provide specific sites for the nucleation and growth of perovskite QDs, thus significantly reducing fluorescence degradation and improving the stability of perovskite QDs. 53,54 In 2017, Zeng et al reported a one-pot and universal strategy for the synthesis of highly luminescent, environmentally stable CsPbBr 3 QDs/A-SiO 2 composite powders by amino-mediated anchoring of perovskite QDs to SiO 2 surfaces ( Fig. 3a ).…”