Utilizing the Undesirable Oxidation of Lead-Free Hybrid Halide Perovskite Nanosheets for Solar-Driven Photocatalytic C(sp 3 )─H Activation: Unraveling the Serendipity.

Hybrid halide perovskites (HHPs), whose every branch generates intrusiveness, have been utilized in solar cells from a broader perspective. However, the inclusiveness of employing HHP as a photocatalyst is in its initial stage. This study mainly focuses on the unexpected utilization of, so far, undesirable material vacancy-ordered MA 2 SnBr 6 quantum dots synthesized from MASnBr 3 nanosheets. Here, the quantum confinement grounded a large blue shift in ultraviolet (UV) and photoluminescence (PL) spectra with a Stokes shift of 420 meV, where the band gap increase is observed as size decreases in MA 2 SnBr 6 . Remarkably, MA 2 SnBr 6 exhibits air and moisture stability, better charge transfer, and high oxidation potential compared to MASnBr 3 . The first-principles-based atomistic computations reveal the strain relaxation in the Sn-Br framework that structurally stabilizes the MA 2 SnBr 6 lattice. Furthermore, the direct band gap and strongly localized valence band edge give rise to a new potential photocatalyst MA 2 SnBr 6 for efficient solar-driven C(sp 3 )─H activation of cyclohexane and toluene under ambient conditions.