3D-cavity-confined CsPbBr₃ quantum dots for visible-light-driven photocatalytic C(sp³)–H bond activation

Abstract

Metal halide perovskite (MHP) quantum dots (QDs) offer immense potential for several areas of photonics research due to their easy and low-cost fabrication and excellent optoelectronic properties. However, practical applications of MHP QDs are limited by their poor stability and, in particular, their tendency to aggregate. Here, we develop a two-step double-solvent strategy to grow and confine CsPbBr₃ QDs within the three-dimensional (3D) cavities of a mesoporous SBA-16 silica scaffold (CsPbBr₃@SBA-16). Strong confinement and separation of the MHP QDs lead to a relatively uniform size distribution, narrow luminescence, and good ambient stability over 2 months. In addition, the CsPbBr₃@SBA-16 presents a high activity and stability for visible-light-driven photocatalytic toluene C(sp³)–H bond activation to produce benzaldehyde with ˜730 µmol g^–1 h^–1 yield rate and near-unity selectivity. Similarly, the structural stability of CsPbBr₃@SBA-16 QDs is superior to that of both pure CsPbBr₃ QDs and those confined in MCM-41 with 1D channels.

Keywords

3D cavity silica / C(sp³)–H bond activation / perovskite quantum dots / photocatalysis / stability