Halogen substitution of aromatic cations for phase transition control and high-efficiency luminescence in 0D manganese-based hybrid perovskites

Two 0D Mn bromides, (2,5-DFBTP) ₂ MnBr ₄ (1) and (2-Cl-5-FBTP) ₂ MnBr ₄ (2), 1 shows a reversible phase transition where 2 does not. But PLQY increases from 58% (1) to 93% (2) via C–Cl⋯Br halogen bonding to improve lattice rigidity, enhancing luminescence, and demonstrates halogen synergy engineering.