Resonantly Enhanced White-Light Emission Involving Energy and Charge Transfer in One-Dimensional Hybrid Material: (ABT)2[PbBr3]

This work focuses on the white light emission process occurring in a new organic–inorganic hybrid metal halide material, with the formula (C 7 H 12 N 2 S) 2 [PbBr 3 ] abbreviated as (ABT) 2 [PbBr 3 ]. Its structure consists of one-dimensional PbBr 3 twin chains surrounded by 2-aminobenzothiazole (ABT) organic cations. The introduction of the optically active organic ligand into the organic–inorganic hybrid material leads to original optical properties; indeed, under UV irradiation, this material shows a white light emission with an impressive intensity that can be seen even with the naked eye. The photoluminescence (PL) spectrum is characterized by a large emission band covering a wide range of the visible spectrum and composed of blue, green, yellow, and red components at around 450, 475, 530, and 580 nm, respectively. PL measurements with various excitations show that white light emission occurs only in a narrow resonant excitation range at around 3.14 eV (394 nm). Photoluminescence excitation investigation and density functional theory band structure calculation revealed that this resonant excitation range corresponds to the coincidence of intrinsic distribution of self-trapped states in the inorganic PbBr 3 distorted chain, with the frontier molecular orbitals of the organic cation. In addition, such an interaction between two ionic chromophores placed at very close distances is believed to be accompanied by a Dexter charge/energy transfer.