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 Cs 10 MnSb 6 Cl 30 with a distinctive 10H (10-layer hexagonal) perovskite polytype structure with (hcccc) 2 stacking. Cs 10 MnSb 6 Cl 30 has 30% B-site vacancies ordered at both corner- and face-sharing sites, resulting in [MnSb 6 Cl 30 ] 10- n 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 Cs 4 MnSb 2 Cl 12 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.