Pressure‐Induced Excitation‐Dependent Emission Color Tuning and Enhancement in 1D Zigzag Edge‐Sharing Perovskites (C6H10N2)PbX4 (X = Br, Cl)

Abstract 1D zigzag edge‐sharing perovskites have generated intense research interest due to their unique structures and optoelectronic properties. Recent efforts have focused on refining these structures to enhance their efficiency across various applications. Herein, high‐pressure is utilized to modulate the properties of two Pb‐based perovskites, (AMP)PbCl 4 and (AMP)PbBr 4 (where AMP 2+ = C 6 H 10 N 2 2+ ), characterized by 1D zigzag edge‐sharing [PbX 4 ] 2− ∞ chains linked by AMP through hydrogen bonding. An inverse excitation‐dependent emission phenomenon and emission enhancement are observed in these two perovskites, attributed to the contraction of inhomogeneously coordinated [PbX 6 ] 4− octahedra. Pressure‐induced lattice contraction promotes the overlap of Pb and X orbitals, resulting in a decrease in the bandgap. Concurrently, pressure‐induced phase transitions, due to the distortion of [PbX 6 ] 4− octahedra, lead to discontinuous decreases in the bandgap. These high‐pressure optical and structural explorations facilitate the systematic design of halide perovskites with desired characteristics.