Efficient in‐Plane Exciton Transport in a Discontinuous Layered Lead‐Bromide Perovskite

This study reports a new class of two‐dimensional lead‐bromide perovskite based on monovalent 4‐aminomethylbenzoic acid (AMBA) cations featuring a discontinuous inorganic layer. Strong hydrogen‐bonding interactions at the interlayer between AMBA molecules impose structural rigidity that prevents the formation of continuous metal‐halide layers, instead generating isolated linear islands of three edge‐sharing [PbBr 6 ] 4 − octahedra (Pb 3 Br 14 ). The anisotropic in‐plane arrangement of the structure is confirmed by angle‐resolved polarized Raman spectroscopy, which reveals directional vibrational modes aligned with the octahedral island orientation. Despite the discontinuous lattice, transient photoluminescence microscopy demonstrates efficient in‐plane exciton transport. Transport is strongly anisotropic, with the diffusion coefficient along the c ‐axis (0.149 cm 2 /s) exceeding that along the a ‐axis (0.042 cm 2 /s) by over threefold. This anisotropy is attributed to preferential near‐field resonant energy transfer between the anisotropically oriented islands, as confirmed by numerical simulations, offering an efficient alternative transport mechanism in discontinuous layered perovskites.