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 MA2SnBr6 quantum dots synthesized from MASnBr3 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 MA2SnBr6. Remarkably, MA2SnBr6 exhibits air and moisture stability, better charge transfer, and high oxidation potential compared to MASnBr3. The first-principles-based atomistic computations reveal the strain relaxation in the Sn-Br framework that structurally stabilizes the MA2SnBr6 lattice. Furthermore, the direct band gap and strongly localized valence band edge give rise to a new potential photocatalyst MA2SnBr6 for efficient solar-driven C(sp3)─H activation of cyclohexane and toluene under ambient conditions.
Keywords: C─H activation; hybrid halide perovskite; lead-free perovskites; photocatalysis; quantum dots.