Enhanced Photoluminescence and Reduced Dimensionality via Vacancy Ordering in a 10H Halide Perovskite

Vacancy-ordered halide perovskites have received great interest in optoelectronic applications. In this work, we report the novel inorganic halide Cs₁₀MnSb₆Cl₃₀ with a distinctive 10H (10-layer hexagonal) perovskite polytype structure with (hcccc)₂ stacking. Cs₁₀MnSb₆Cl₃₀ has 30% B-site vacancies ordered at both corner- and face-sharing sites, resulting in [MnSb₆Cl₃₀]^10- columns, i.e., a reduction of octahedral connectivity to 1D. This results in enhanced photoluminescence in comparison to the previously reported 25% vacancy-ordered 3C polytype Cs₄MnSb₂Cl₁₂ with 2D connectivity. This demonstrates not only the existence of the 10H perovskite structure in halides but also demonstrates the degree of B-site deficiency and stacking sequence variation as a direction to tune the optical properties of perovskite polytypes via vacancy rearrangements.